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View Full Version : Surge brakes pulsating or "machine gunning"


kgrove
05-19-2012, 06:45 PM
'08 X15 with stock MC trailer. I had the master cylinder on my surge brakes replaced, and afterwards when I brake, the surge brakes pulse on and off as the trailer slams into the hitch, releases, slams in again, and keeps doing this over and over. I was told this is called "machine gunning", though i dont know if that is a universal term or just the local dealer's internal term. They thought it was a bad shock or dampener so that when I braked, the trailer would slam the master cylinder causing the brakes to engage to hard and/or make the trailer rebound backwards ands start a vicious cycle. They replaced the dampener and it's still doing it, although not as often or severely.

The obvious answer is to take it back and make them fix it but they just as obviously are not sure what's wrong or they would have fixed it already. Any ideas? What else could cause this if I have a new master cylinder and shock/dampener? I will be taking it back to make them fix it, but I'd prefer giving them some suggestions as to what to look for since they've done what they know to do.

petermegan
05-19-2012, 07:35 PM
Wonder whether it was bled properly. Air in the system could compress and cause an intermittant application of the brakes. Only guessing, never experienced it.

thatsmrmastercraft
05-19-2012, 07:55 PM
I'm no trailer brake expert, but I agree, it sounds like air in the lines.

mikeg205
05-19-2012, 09:12 PM
I had the same problem... #1 make sure bled correctly, #2 make sure shock in actuator ok, #3 - there are wear cushions that need to be periodically replaced. Mine was pulsating side to side...spoke with pacific trailers where I get my parts. Bought $25 bucks of parts - problem solved...do y ou have the UFP-A60 Actutor?

kgrove
05-21-2012, 03:33 PM
I have no idea what kind of actuator I have - whatever was standard on 2008 MC stock trailers. I'll suggest they check the lines were properly bled and have no air. After that I'm flummoxed.

mikeg205
05-21-2012, 06:30 PM
Take a picture and put it up here...I'll most likely be able to identify.

kgrove
05-21-2012, 09:29 PM
Will do, but it will be a few days before I see my boat.

Stutsman230
05-21-2012, 09:48 PM
I have been told that there is an orifice in the actuator. The old orifice may have been smaller. Talk to Jim at Arizona Luxury Marine about your problem.

rgardjr1
05-21-2012, 10:24 PM
I have been told that there is an orifice in the actuator. The old orifice may have been smaller. Talk to Jim at Arizona Luxury Marine about your problem.

I'm in the process of replacing the Reliable actuator on my 2006 trailer with a UFP actuator. I can confirm that there was a fitting that came off my old master cylinder and connected to the brake line that had a much smaller orifice than the brake line would. I haven't got everything put back together yet, but I will take a picture of the of the fitting tomorrow and post it here tomorrow. I would be nice to confirm that this fitting is needed before I put mine back together and bleed the brake lines.

mikeg205
05-22-2012, 08:54 AM
I have been told that there is an orifice in the actuator. The old orifice may have been smaller. Talk to Jim at Arizona Luxury Marine about your problem.

It's critical to have the brakes bled properly. If you have the UFP A60 or any UFP master cylinder it also has to be bled - according to UFP tech. Two holes in UFP master cylinder from UFP in the M-cylinder I have. Also, a shock absorber in the actuator will cause the piston in the master cylinder to move quicker on the rebound when trailer slows down.

I had my issue upon light breaking....You can easily see the actuator bucking forward and backward and causing the chattering sound...per UFP - new shock, wear pads and properly bled lines.

rgardjr1
05-22-2012, 01:07 PM
Here is the fitting with the small orifice:
79195


Sent from my iPhone using Tapatalk

SpryBeast
05-22-2012, 02:11 PM
My dealer also suggested that I install the fitting with the smaller hole for this same problem. The one they got me was part number #650680, orifice .0018. To be honest I can't speak to it's effectiveness as it's been sitting on my workbench for 2 years.

mikeg205
05-22-2012, 03:09 PM
I would contact dennis at UFP...

http://www.ufpnet.com/ContactUs/tabid/60/Default.aspx

dennis is the TN location.

rgardjr1
05-22-2012, 04:11 PM
My dealer also suggested that I install the fitting with the smaller hole for this same problem. The one they got me was part number #650680, orifice .0018. To be honest I can't speak to it's effectiveness as it's been sitting on my workbench for 2 years.

Do you know if you have the UFP actuator on your trailer? The reverse lockout solenoid on the Reliable actuator has a different thread type than the UFP actuator. I tried to source a fitting to convert it, but I haven't had any luck. I wish I had some one at my local Mastercraft dealership that could answer questions for me, but I've struck out so far.

SpryBeast
05-22-2012, 04:34 PM
Do you know if you have the UFP actuator on your trailer? The reverse lockout solenoid on the Reliable actuator has a different thread type than the UFP actuator. I tried to source a fitting to convert it, but I haven't had any luck. I wish I had some one at my local Mastercraft dealership that could answer questions for me, but I've struck out so far.

Pretty sure mine is Reliable.

kgrove
05-22-2012, 04:48 PM
I still don't have a picture, but my dealer tells me I have a Reliable actuator - apparently no longer used on Mastercraft. He replaced the master cylinder and the shock already and also did something about the size of some kind of orifice (all these repairs are doing something to the size of one of my orifices as well).

I'm told Reliable is out of business and parts are unavailable so my only choice is to switch to UFP (Unique Functional Products).

rgardjr1
05-22-2012, 05:02 PM
I still don't have a picture, but my dealer tells me I have a Reliable actuator - apparently no longer used on Mastercraft. He replaced the master cylinder and the shock already and also did something about the size of some kind of orifice (all these repairs are doing something to the size of one of my orifices as well).

I'm told Reliable is out of business and parts are unavailable so my only choice is to switch to UFP (Unique Functional Products).

I'm in the same boat. My Reliable master cylinder went T.U. and I'm replacing it with a UFP. I wasn't going to use the orifice because the threads didn't work, but now it sounds like I need to. I'm pretty sure the newer Mastercraft trailers use the UFP actuators so there should be an orifice part available through Mastercraft. Keeping my fingers crossed.

mikeg205
05-22-2012, 05:09 PM
where was that fitting....coming out of the master cylinder? connected to a small hose feeding back to the master cylinder reservoir?

rgardjr1
05-22-2012, 06:29 PM
where was that fitting....coming out of the master cylinder? connected to a small hose feeding back to the master cylinder reservoir?

The fitting was connected to the reverse lockout solenoid one one side and the flexible brake line that runs to the brakes on the other.

mikeg205
05-22-2012, 06:46 PM
That would not cause the chattering. When I spoke with the folks at UFP the only things that cause that noise is a bad shock absorber, air in the lines, or a bad master cylinder...in my case the shock was bad.

rgardjr1
05-22-2012, 07:05 PM
That would not cause the chattering. When I spoke with the folks at UFP the only things that cause that noise is a bad shock absorber, air in the lines, or a bad master cylinder...in my case the shock was bad.

There are some old threads around here that talk about this problem when towing the trailer empty and adding the smaller orifice to correct this. I don't think I'm going to waste anymore time trying to track this part down. I only use my trailer twice a year and I only have to drive a total of 20 miles to do this. I'll put everything back together without this piece and see if I have this problem. If I do I'll have all summer to play around with an empty trailer.

rgardjr1
05-23-2012, 05:50 PM
I would contact dennis at UFP...

http://www.ufpnet.com/ContactUs/tabid/60/Default.aspx

dennis is the TN location.

I received and email from Dennis today about whether or not I needed to keep the fitting inline. His response:
"Rick, It should not be a problem to use the fitting if needed. The UFP solenoid has one built into it so, your decision whether or not to leave it in.
Dennis"
So it sounds like the UFP solenoid eliminates the need for this fitting. I'll let everyone know what I experience after I get the new actuator installed and brakes working again.

jakethebt
05-23-2012, 10:25 PM
I am not so sure that air in the lines is going to cause this issue.

Air in the lines is bad because air is compressible. If you have air in the lines, the air compresses instead of transferring the master cylinder pressure via fluid to the brakes. That means that as your trailer slides forward, the pressure in the master cylinder is compressing the air instead of moving brake fluid to the brakes, thus no brakes. I would not be looking at air in the system to cause this issue.

It sounds to me like the brakes are over adjusted or grabbing. If you are driving down the road and apply the vehicle brakes, the vehicle slows down, the boat slides forward and applies pressure to the master cylinder. The master cylinder applies pressure to the trailer brakes and the trailer begins to slow down. If the brakes are providing too much stopping force, the trailer will slow more than the vehicle and the brakes will stop applying. Keep in mind, the vehicle is still slowing down this entire time. The boat is now going to catch back up with the slowing vehicle and the brakes will apply again. When this happens, the brakes will apply too much (again) and the trailer will slow down way to much (again) and thus stop applying. I think this is a situation that can explain your problem better of hammering or whatever you want to call it.

I would look for reasons the brakes are applied too hard.

kgrove
05-24-2012, 10:18 AM
That was exactly my thought - brakes grabbing too tight. I suggested that to the shop, but they said there weren't adjustments to calibrate how hard the brakes grab. The brakes keep grabbing harder until the momentum of the boat stops compressing the master cylinder even further and the shock is supposed to slow down how fast this happens. If the dampening mechanism isn't working correctly you get what you're describing - trailer slams actuator, brakes grab too hard slowing trailer more tha truck, brakes release and process starts all over again.

I'm really at a loss. I've had both the master and the shock replaced and the problem is less severe, but still there. The mechanics are now suggesting replacing the calipers, but this would cost somewhere around $1,000. I hate this idea since we don't even know there is anything wrong with them, they just want to replace them because they've replaced everything else and are out of ideas. I think I'd start over and replace the whole actuator mechanism even though I just replaced the main parts before I did that.

Ideas? Suggestions?

rgardjr1
05-24-2012, 02:02 PM
Ideas? Suggestions?

The UFP actuator comes apart very easily with a pair of snap ring pliers. I would take the actuator apart and look at the shock. Put it in a vise and see if it's working in both directions. Sounds like the master cylinder is working since the brakes are grabbing. There is also a spring on the master cylinder that will affect how quickly pressure can be applied on the brakes. The UFP actuators are pretty inexpensive (~$150) relative to the $1000 to replace the rotors and calipers. The new one will basically drop in and all you'll have to do is bleed the brakes. I'm still a few days away from messing around with my retro fit project to replace my shot Reliable actuator, but when I tore into the Reliable actuator I had problems with both the master cylinder and the shock. In my case I think the master cylinder failed and then when I towed the boat with out brakes the shock got over worked and failed. Good luck!

petermegan
05-24-2012, 02:12 PM
I am not convinced either way but may I point out that a very small amount of air would compress when the tow vehicle slowed and the master cylinder applies pressure, brakes would be applied then the small pocket of compressed air can bounce off and on the hydraulic pressure needed to apply the wheel cylinders. Agreed a large amount of air would mean little or drastically reduced braking.

jakethebt
05-24-2012, 10:24 PM
I dont think there is an adjustment on the calipers either. I think that only applied to the old drum brakes. I dont know why the calipers would cause grabbing. If you have a bad seal it leaks. If the piston is rusted in the bore, it will not move. If it were a case of the calipers not releasing, that could be resolved by new calipers or a rebuild. I really cant think of a reason why you would replace the calipers. I would be looking at the apply system. The master cylinder and the shock.

sand2snow22
05-24-2012, 11:32 PM
I dont think there is an adjustment on the calipers either. I think that only applied to the old drum brakes. I dont know why the calipers would cause grabbing. If you have a bad seal it leaks. If the piston is rusted in the bore, it will not move. If it were a case of the calipers not releasing, that could be resolved by new calipers or a rebuild. I really cant think of a reason why you would replace the calipers. I would be looking at the apply system. The master cylinder and the shock.

I've had to replace several calipers on MC trailers. They get stuck and don't release. Rotor, wheel and tire get really hot!

sand2snow22
05-24-2012, 11:35 PM
The UFP actuator comes apart very easily with a pair of snap ring pliers. I would take the actuator apart and look at the shock. Put it in a vise and see if it's working in both directions. Sounds like the master cylinder is working since the brakes are grabbing. There is also a spring on the master cylinder that will affect how quickly pressure can be applied on the brakes. The UFP actuators are pretty inexpensive (~$150) relative to the $1000 to replace the rotors and calipers. The new one will basically drop in and all you'll have to do is bleed the brakes. I'm still a few days away from messing around with my retro fit project to replace my shot Reliable actuator, but when I tore into the Reliable actuator I had problems with both the master cylinder and the shock. In my case I think the master cylinder failed and then when I towed the boat with out brakes the shock got over worked and failed. Good luck!

You don't need brakes :o You don't have to tow too far :D I recently towed a 2005 Super Air without trailer brakes. Probably only weighs 4,300lbs with the trailer. The trailer has brakes, but they are drum and they don't work. It is a P.O.S. trailer. Tundra did pretty well, except when I had to stop quickly at a red light. The boat was really pushing against the truck. I could smell hot brakes. Makes me wonder about those Tundra commercials? 8p

jakethebt
05-25-2012, 06:36 AM
I've had to replace several calipers on MC trailers. They get stuck and don't release. Rotor, wheel and tire get really hot!

I have heard that the calipers do stick and need replacing, but I dont think that is the root cause of machine gunning. If the trailer we were talking about had drum brakes, I would say they need adjusting. I dont think the old drum brake were self adjusting, so in other words you had to adjust them. The procedure was adjust until the shoes make contact and then back off 5 clicks. If you did not back off and then used the trailer, I bet you would get very grabby brakes or machine gunning. I have never tried, just a guess.

jakethebt
05-25-2012, 06:38 AM
You don't need brakes :o You don't have to tow too far :D I recently towed a 2005 Super Air without trailer brakes. Probably only weighs 4,300lbs with the trailer. The trailer has brakes, but they are drum and they don't work. It is a P.O.S. trailer. Tundra did pretty well, except when I had to stop quickly at a red light. The boat was really pushing against the truck. I could smell hot brakes. Makes me wonder about those Tundra commercials? 8p

I had the same thing happen in my F150... no hot brakes. The rest of the truck, tranny and engine have issues but the brakes seemed pretty good.

kgrove
05-29-2012, 04:24 PM
Any idea what it takes to replace a Reliable actuator with a UFP? I heard you have to do some modifications to either the actuator or the tongue as the bolt and cutout patterns are different. We can't get parts for the Reliable.

Even though I've already had the master cylinder and shock replaced, I'm still having the problem. The dealer is convinced I need to replace all the calipers, but to me the problem sounds more like the actuator mechanism. I'm thinking either the master cylinder or shock, even though new, are defective. I know four new calipers are going to cost $1000-$1200, so if I can replace the actuator mechanism for much cheaper I may try that. My dealer and I don't agree on the next step. He is convinced the problem is the water in the master cylinder rusted the internal mechanisms of the calipers so they don't work correctly. I hate replacing parts I don't know are bad just because I've already replaced everything else.

rgardjr1
05-29-2012, 05:14 PM
Any idea what it takes to replace a Reliable actuator with a UFP? I heard you have to do some modifications to either the actuator or the tongue as the bolt and cutout patterns are different. We can't get parts for the Reliable.

I'm in the process of doing this right now. I bought a UFP A-60 actuator and the weld on outer sleeve. I've got a swing away tongue so I took the old tongue to the machine shop so the can cut the top and bottom pieces off the old swing away tongue and weld them on to the new outer UFP sleeve. The pins that hold the Reliable actuator in the sleeve are not the same as the UFP. You might be able to drill some holes, but the UFP actuator was longer that the Reliable so this may or may not work. I've got to stop by the machine shop tonight to see if he's gotten to my project yet.

Sodar
05-29-2012, 05:36 PM
Is Reliable out of business or are you just upgrading?

I've always liked the UFP products.

rgardjr1
05-29-2012, 05:51 PM
Is Reliable out of business or are you just upgrading?

Reliable is still in business, but there are no parts available for their actuators or mastercylinders. I talked to some one at Reliable that told me Mastercraft may still have some old stock available. Mastercraft said they were out of parts, but would build a new swing away tongue for $800. I think Mastercraft is using the UFP brake actuators on their trailers now. I figured I could fix it for a lot less-the UFP actuator and sleeve was $181 which leaves me a lot of money to spend at the machine shop.

mikeg205
05-29-2012, 07:27 PM
the chattering or machine gunning sound can be also caused by warped rotors and warped drums...when mine chattered -- they never did it after I pulled the boat out. Hot rotors and cool water....just like blowin thru a puddle with your car after some hard breaking...

mramerman@gmail.com
07-31-2013, 04:17 PM
I have a 2010 reliable trailer that this same issue.

Added a ground to the reverse lock out--no fix

Found the rotors were warped. Fixed. Still machine gun.

Being told it is likely a week damper---reliable out of business (or part not available). Need to replace entire swing arm with UFP = $1200.00

Is this the route to go?

amcmac
07-31-2013, 04:48 PM
You can get a whole new reliable setup from waymires for$450. That includes a new outer sleeve and new master cylinder/actuator

Traxx822
07-31-2013, 04:57 PM
Sorry to chime in after 4 pages but I didn't see anything to suggest just using the trailer for a bit first.

Just at the beginning of this season I had all the brakes and lines etc etc replaced new. I hardly ever use my trailer. When I do the brakes machine gun for a while. After about 20 stops it goes away.

You may only be experiencing this because you don't use your trailer like you said twice a year for 20 miles.

Just a thought

Sent from my HTC One using Tapatalk 2

mramerman@gmail.com
07-31-2013, 06:47 PM
Sorry to chime in after 4 pages but I didn't see anything to suggest just using the trailer for a bit first.

Just at the beginning of this season I had all the brakes and lines etc etc replaced new. I hardly ever use my trailer. When I do the brakes machine gun for a while. After about 20 stops it goes away.

You may only be experiencing this because you don't use your trailer like you said twice a year for 20 miles.

Just a thought

Sent from my HTC One using Tapatalk 2

I am not sure that comment was directed towards me. I tow my trailer an average of 4 - 500 miles a month (maybe more).

mzimme
07-31-2013, 07:08 PM
I have a 2010 reliable trailer that this same issue.

Added a ground to the reverse lock out--no fix

Found the rotors were warped. Fixed. Still machine gun.

Being told it is likely a week damper---reliable out of business (or part not available). Need to replace entire swing arm with UFP = $1200.00

Is this the route to go?

I just went through replacing my reliable swing away tongue with a UFP part. Waymires was the route I took... they have a direct replacement that literally is just a direct swap. You'll need to unhook the brake line, unbolt the swing away bolt, pull the pin, pull off the old reliable POS actuator, and bolt on the new UFP actuator, reconnect the brake lines, bleed the brakes, and voila... done.

Cost me $422 shipped to my door, and I bled them myself. Pretty straight forward job, just make sure you have a breaker bar for that bolt that holds the tongue on. Use PB blaster a few days in advance to start the penetration and you should be good.

Traxx822
07-31-2013, 07:11 PM
I am not sure that comment was directed towards me. I tow my trailer an average of 4 - 500 miles a month (maybe more).

Nope, it was to the OP. Which is the only post I read completely and didn't realize topics had changed.

Sorry

Sent from my HTC One using Tapatalk 2

mramerman@gmail.com
07-31-2013, 07:30 PM
I just went through replacing my reliable swing away tongue with a UFP part. Waymires was the route I took... they have a direct replacement that literally is just a direct swap. You'll need to unhook the brake line, unbolt the swing away bolt, pull the pin, pull off the old reliable POS actuator, and bolt on the new UFP actuator, reconnect the brake lines, bleed the brakes, and voila... done.

Cost me $422 shipped to my door, and I bled them myself. Pretty straight forward job, just make sure you have a breaker bar for that bolt that holds the tongue on. Use PB blaster a few days in advance to start the penetration and you should be good.

Awesome advice. What is "PB blaster?" What penetration should I be concerned with?

mramerman@gmail.com
08-01-2013, 03:23 PM
I just went through replacing my reliable swing away tongue with a UFP part. Waymires was the route I took... they have a direct replacement that literally is just a direct swap. You'll need to unhook the brake line, unbolt the swing away bolt, pull the pin, pull off the old reliable POS actuator, and bolt on the new UFP actuator, reconnect the brake lines, bleed the brakes, and voila... done.

Cost me $422 shipped to my door, and I bled them myself. Pretty straight forward job, just make sure you have a breaker bar for that bolt that holds the tongue on. Use PB blaster a few days in advance to start the penetration and you should be good.

Update. Ordered the actuator for Waymires today. Will arrive next week. I will take photos and post through installation.

mzimme
08-01-2013, 03:42 PM
Awesome advice. What is "PB blaster?" What penetration should I be concerned with?

PB blaster is a penetrating oil that will help if the loosen bolt that holds your tongue to the trailer if it has any rust on it. If your swing away tongue swings without much resistance, you're probably good and won't need any. If you keep your trailer outside, it will help you out.

mikeg205
08-04-2013, 12:12 PM
Thought my trailer brake "machine gunning" issue went away - but after working on my trailer for a few seasons U have found -

#1 - if tongue of trailer not level especially if ball to high - actuator will tend to chatter...
#2 - out of round drums actuator will chatter
#3 - if heading down a steep hill - trailer will chatter - found out yesterday on this one when heading south on rt. 53 in Duluth... no chatter on 1600 round trip until this huge down hill stretch. No chatter after this stretch.

mramerman@gmail.com
08-11-2013, 09:56 PM
Bye bye Reliable! New Actuator arrived. Off to paint shop this week to get the sleeve paint matched. More photos will follow.

kgrove
08-14-2013, 05:29 PM
Bye bye Reliable! New Actuator arrived. Off to paint shop this week to get the sleeve paint matched. More photos will follow.

If you're doing the work yourself (other than painting), I'd love to see you document what you had to do. I've had problems with my Reliable master cylinder so I know its just a matter of time before I have to do a tongue-ectomy myself. Unfortunately I have the mechanical experience of your average 8 yr old...

I had my dealer do the tongue on my last trailer when it went bad, but this was before the waymire option was available and it required a custom job. The only downside I found, and hopefully this waymire version corrects for it, was the Reliable setup was a couple inches shorter in overall length, so the safety cables were a bit tighter than I would have liked - not enough to warrant replacing them with longer ones, but enough to annoy me.

mramerman@gmail.com
08-14-2013, 05:43 PM
If you're doing the work yourself (other than painting), I'd love to see you document what you had to do. I've had problems with my Reliable master cylinder so I know its just a matter of time before I have to do a tongue-ectomy myself. Unfortunately I have the mechanical experience of your average 8 yr old...

I had my dealer do the tongue on my last trailer when it went bad, but this was before the waymire option was available and it required a custom job. The only downside I found, and hopefully this waymire version corrects for it, was the Reliable setup was a couple inches shorter in overall length, so the safety cables were a bit tighter than I would have liked - not enough to warrant replacing them with longer ones, but enough to annoy me.

"Tongue-ectomy." That is very funny.

Happy to help however I can. I have some mechanical experience---lets put this at an average 10year old, which is probably why I am so confident I can resolve this myself.

So far, the removal was easy. The brake line itself screws out of the actuator. There are only two wires: blue, which I presume is the reverse lock-out and white ground.

Will be uploading photos as I install. Picking up the actuator sleeve from the paint shop today.

psbudz
08-16-2013, 03:45 PM
@mramerman Pictures man, pictures!

mramerman@gmail.com
08-20-2013, 01:21 PM
Well the project is complete. Overall it was not a terribly difficult process.

Removing the existing Reliable actuator involved disconnecting brake line, reverse shut out wire and the ground wire. Once those were disconnected, taking the actuator off was easy---one bolt.

We had a friend who owns a body shop paint match the new UFP actuator sleeve. We reconnected the brake line, reverse shut out wire and ground. We added brake fluid and then bleed the brakes. Bleeding was probably the toughest--we couldn't get a good seal using the vacuum system so we had to do it the old fashion way.

Please note, the new UFP actuator is longer than the existing Reliable. Safety chains etc., are plenty long for the new set up.

I do like the attachment mechanism better than the Reliable option.

mramerman@gmail.com
08-22-2013, 05:03 PM
It's critical to have the brakes bled properly. If you have the UFP A60 or any UFP master cylinder it also has to be bled - according to UFP tech. Two holes in UFP master cylinder from UFP in the M-cylinder I have. Also, a shock absorber in the actuator will cause the piston in the master cylinder to move quicker on the rebound when trailer slows down.

I had my issue upon light breaking....You can easily see the actuator bucking forward and backward and causing the chattering sound...per UFP - new shock, wear pads and properly bled lines.

Mike:

I have taken the following steps:

I installed the actuator on the trailer
Attached the blue reverse lock out wire.
Attached the white ground wire to the solenoid
I filled the brake fluid reservoir
We bled the brakes one wheel at a time front to back while apply pressure to the actuator

I think I am done? However, you mention the following, "If you have the UFP A60 or any UFP master cylinder it also has to be bled - "

How do you bleed the master cylinder?

thanks!

mikeg205
08-22-2013, 05:08 PM
Mike:

I have taken the following steps:

I installed the actuator on the trailer
Attached the blue reverse lock out wire.
Attached the white ground wire to the solenoid
I filled the brake fluid reservoir
We bled the brakes one wheel at a time front to back while apply pressure to the actuator

I think I am done? However, you mention the following, "If you have the UFP A60 or any UFP master cylinder it also has to be bled - "

How do you bleed the master cylinder?

thanks!


If you're your bled thru all lines... you are good... some times the master cylinder needs to be primed - was having trouble and called UFP - so I I had to pour brake fluid into master cylinder before I installed it..(had to take it out) so make sure there was no air in master cylinder - it was weird.

mramerman@gmail.com
08-22-2013, 05:13 PM
If you're your bled thru all lines... you are good... some times the master cylinder needs to be primed - was having trouble and called UFP - so I I had to pour brake fluid into master cylinder before I installed it..(had to take it out) so make sure there was no air in master cylinder - it was weird.

Thanks for the reply. We worked really hard to bleed the brakes. One guy was applying pressure the actuator and the other opening the individual brake valves. Upon manual testing (spinning the rotors) we can get brakes to bite. It is really hard to tell behind my F250 if the brakes are working or not.

I have a sneaking suspicion there maybe air remaining in the line for two (not so obvious) reasons: 1) it seem like I would really be able to feel the trailer braking and not producing incremental force against the truck (i think I could feel that in the past)---I do not now and 2) After several rounds of bleeding and doing one last test--we would get a blast of air. We would then bleed each valve 2 - 3x, ensuring a steady stream of fluid only to come across another air bubble.

mikeg205
08-22-2013, 05:16 PM
Thanks for the reply. We worked really hard to bleed the brakes. One guy was applying pressure the actuator and the other opening the individual brake valves. Upon manual testing (spinning the rotors) we can get brakes to bite. It is really hard to tell behind my F250 if the brakes are working or not.

I have a sneaking suspicion there maybe air remaining in the line for two (not so obvious) reasons: 1) it seem like I would really be able to feel the trailer braking and not producing incremental force against the truck (i think I could feel that in the past)---I do not now and 2) After several rounds of bleeding and doing one last test--we would get a blast of air. We would then bleed each valve 2 - 3x, ensuring a steady stream of fluid only to come across another air bubble.


Use a ratcheting belt - much easier - wrap the belt around bow support and actuator...wratchet to complete inserted position - bleed... release belt... add fluid if needed repeat... no straining - no pain - takes half the time.

mramerman@gmail.com
08-22-2013, 05:19 PM
Use a ratcheting belt - much easier - wrap the belt around bow support and actuator...wratchet to complete inserted position - bleed... release belt... add fluid if needed repeat... no straining - no pain - takes half the time.

dude! duh. GREAT idea. Gosh, we were killing our backs squeezing that damn thing.

On it.

mikeg205
08-22-2013, 05:30 PM
dude! duh. GREAT idea. Gosh, we were killing our backs squeezing that damn thing.

On it.

Yeah got the idea when I saw my son straining... we popped a couple of cold ones and brain stormed... had one so it was a freebie solution. It was that or get a pressurized brake bleeder - but I didn't want to spend the cash on that...

awesome to share solutions... love this forum.. :)

mramerman@gmail.com
08-22-2013, 05:34 PM
Yeah got the idea when I saw my son straining... we popped a couple of cold ones and brain stormed... had one so it was a freebie solution. It was that or get a pressurized brake bleeder - but I didn't want to spend the cash on that...

awesome to share solutions... love this forum.. :)

Could not agree more.

We couldn't get the pressurized brake bleeder to work. There isn't enough room on the nipple for the hose line to connect and get box wrench around to open and close the valve.

I can easily see where we went wrong... we didn't have the cold ones, encouraging the break in action to consider simpler alternatives.

I agree, love this forum too. Great to share passion for the sport, boat and good old fashion ingenuity.

JDC
08-22-2013, 10:01 PM
dude! duh. GREAT idea. Gosh, we were killing our backs squeezing that damn thing.

On it.Look in the manual that came with your actuator. It shows where to insert a small flat blade screwdriver in a hole in the bottom and pry on the plunger for the master cylinder. You also need to hold in the release lever so the plunger will release when you let off of your screwdriver, but it's all very easy. (page 24, with illustration on 25)
Here is a link to the manual > http://www.ufpnet.com/Portals/0/PDFs/A-60,%2075%20_%2084%20Actuator%20Maintenance.pdf

I had my 11 year old daughter sitting on a stool at the actuator with the screwdriver prying for me. I explained the communication we needed between us (she tells me when she's holding; I tell her when the bleeder is closed etc.) and we had all 4 wheels bled in 15 minutes. We would have had it done sooner if the master cylinder held more than like 1/3 cup of fluid. :rolleyes: Having to get out from underneath and refill it every 3rd or 4th bleed was a pain.

I did bleed mine a 2nd time a few days later as it just didn't feel right. I found I still had air in the left side. The 2nd time I had my wife help me. My daughter had the hang of it quicker but I think at 11... you learn quicker. ;)

Also, (I saw it mentioned in an earlier post) step 1 and 2 on page 24 talks about bleeding the master cylinder. :)

amcmac
08-23-2013, 05:57 AM
Thanks for the reply. We worked really hard to bleed the brakes. One guy was applying pressure the actuator and the other opening the individual brake valves. Upon manual testing (spinning the rotors) we can get brakes to bite. It is really hard to tell behind my F250 if the brakes are working or not.

I have a sneaking suspicion there maybe air remaining in the line for two (not so obvious) reasons: 1) it seem like I would really be able to feel the trailer braking and not producing incremental force against the truck (i think I could feel that in the past)---I do not now and 2) After several rounds of bleeding and doing one last test--we would get a blast of air. We would then bleed each valve 2 - 3x, ensuring a steady stream of fluid only to come across another air bubble.

I know what you mean on reason #1. After I got mine conversion done it felt like they weren't working like they did before. I didn't feel the annoying "clunk" anymore.




Use a ratcheting belt - much easier - wrap the belt around bow support and actuator...wratchet to complete inserted position - bleed... release belt... add fluid if needed repeat... no straining - no pain - takes half the time.







dude! duh. GREAT idea. Gosh, we were killing our backs squeezing that damn thing.

On it.

Another possible solution is to use the trailer winch. I also felt like I got a better "bleed" using that method over the screwdriver method, and you don't have to hold the tab on the bottom. Another point to my statement above, for testing,I put the trailer on jack stands. I had a friend spin a tire and I would pull the plunger/coupler into receiver with the trailer winch. The tire locked up hard to where you couldn't spin it by hand. Repeated the other side and I was golden. It was mentioned earlier or a different thread about pushing the boat in the garage being difficult. I will say after I released the winch, the tires did not spin free until you pulled the coupler all the way out of the receiver.

phil_edgecumbe
02-16-2014, 05:47 AM
Initial Problem:
Problem was the brakes would oscillate at about 1Hz. The harder the car braked the more violent the "machine gunning" was. If the brakes were applied gently then progressively harder the problem did not arise. Stopping in a hurry was not ideal and I needed to fix the problem.

Setup:
1997 Prostar 205 on Mastercraft trailer (2000kg gross weight in total).
Tandem trailer with hydraulic drum brakes on all 4 wheels.
Override brake converted for Australian regulations with 3/4in master cylinder.
Fluid changed and brakes bled.
Brake shoe adjusters backed off 6 clicks.
1/8in gap between override coupling and brake actuating lever.

Solution:
Changed the master cylinder from 3/4in to 7/8in.
No more oscillation under brakes!!

I guess the conversion to different master cylinder caused the system to find it's resonant frequency. Changing it to 7/8in made the brake actuation less sensitive and moved the resonant frequency somewhere else.

I hope this is of value to any other guys in Australia with imported boats with override couplings.

Australian regulations mandate that trailers over 2000kg total weight need self contained electric over hydraulic systems with breakaway connections. I wasn't looking forward to the cost of fitting the system if I didn't have to.

Cloaked
02-16-2014, 01:48 PM
Override brake converted for Australian regulations with 3/4in master cylinder.

Australian regulations mandate that trailers over 2000kg total weight need self contained electric over hydraulic systems with breakaway connections.I have never seen a setup like the brake controller but certainly I am happy happy happy for you that you rid the problem. I cannot stand to have an issue that bugs me to no end....Good solution....

Aside from the funky (relatively speaking) looking brake contraption, you have a nice looking machine. Nice looking cover too....

Best to you in Oz.... As the earth tilts, we're fixing to take up with summer when you are winding down in another month or two or three....

Thanks for the pictures....

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