View Full Version : bleed the brakes?

05-26-2009, 02:23 PM
After the powdercoat, I now need to re-install the brake lines and bleed them. I think I first need to flush/clean out the lines before putting in new fluid.

Any tips on cleaning the lines first? I was thinking brake fluid down the lines and then flush with new fluid.

Any tips on bleeding them once installed?

Sorry.....94' trailer, single axle.

05-26-2009, 02:59 PM
I had to bleed mine after sitting all winter. My mechaanic said gravity works great. Park yoour trailer with the cylinder higher than than wheels and open up the bleeder and let gravity do all the work.You will need a little bit of plastis tubing to go from the bleeder to a small bucket so not to make a mess. Worked great for me.....

05-26-2009, 03:19 PM
Just keep pumping the fluid out until it looks good. One of the best ways is to get or rent one of those vacuum testers. Most of them can be used to bleed brakes. Use that to pump fluid through until your happy, then I pump it and bleed is the old fashion way a couple times to make sure.

05-26-2009, 03:44 PM
Sounds pretty easy...thanks!

Just use standard DOT 3 brake fluid?

05-26-2009, 03:54 PM
Sounds pretty easy...thanks!

Just use standard DOT 3 brake fluid?

I'd have to look to be sure, but i think so

05-29-2009, 10:02 AM
Well I tried to bleed the brakes last night but no success.

I got some brake cleaner and sprayed it down each of the tubes to clean out any debris (dirt, old oil, etc) and then followed it with some compressed air. That worked out great!

I got everything hooked up and tightened, ready to bleed the brakes. I got the trailer on a decent grade so the fluid would flow pretty easily to the downhill wheels. Unfortunately, after filling the master cylinder and openning the bleeder (and then bleeders).....nothing. The fluid level never budged and stayed full. I checked the quick release hose connector at the master cylinder....no oil.

It was getting dark so I decided to call it a day. I backed up and then noticed a little oil on the ground. After investigating, there appeared to be a sliding plate the went over a portion of the master cylinder plug. I also checked the quick release again and there was oil!

So, in order to get the fluid to move to the rear wheels, do I need to have "backward pressure" on the trailer to essentially "engage" the trailer brakes? The sliding plate that moved in reverse covered the master cylinder filler hole about half way and makes it almost impossible to get a funnel in there to keep the level full.

Am I missing something or just applying too much backward pressure?

05-29-2009, 10:52 AM
You need to pump it with a screw driver or pry bar like you would pump the pedal of a car to bleed the brakes. One person pump it about three times, hold it as if to engage the brakes, crack the bleeder, close the bleeder, and do it again over and over until you are not getting any air at all, just oil out of the bleeder.

05-30-2009, 04:28 PM
Thanks for help! I just thought the "gravity feed" idea was just that.....filled by gravity and keeping the reservoir filled. It makes more sense to pump it a few times to get things moving.

I actually found a way to do it myself. I backed the trailer up against a curb and then moved the trailer back and forth about a foot in each direction with the truck still attached (being sure I backed the trailer tires into the curb each time) to simulate pumping the brakes. After 3 lunges back and forth, on the fourth reverse lunge, I held it against the curb and then put the truck in park. This essentially engaged the trailer brakes and kept pressure in the line. I then went back to the furthest bleeder wheel and turned it enough to get the fluid moving out with the occasional air bubble as well.

I then moved the truck forward to "take the pressure off of the trailer brakes" and then topped off the reservoir.

I repeated this about 5 or 6 times until I got good clear fluid coming out of the furthest wheel without any bubbles.

I then moved to the other wheel and repeated the same procedure until I got clean fluid as well.

I think I got it done......solo!

05-30-2009, 07:03 PM
Nicely done. :worthy:I have not found gravity to be of much help because unless you compress the Master Cylinder in the toungue the fluid does not go anywhere. Your method is about the best one man way I have heard of other then using a vacuum brake bleeder.


05-31-2009, 06:43 AM
I actually found a way to do it myself...[clipped]...I think I got it done......solo!

Impressive method for sure!

05-31-2009, 11:04 AM
For future reference... http://ufpnet.com/DiscBrakes/BleedingInstructions/tabid/62/Default.aspx

06-02-2009, 09:37 PM
Bought my power bleeder and adapter from Waymire. Good service, fast shipping and very helpful with questions I had.....


06-07-2009, 06:06 PM
Buy a vacuum bleeder.....

I own one something like this...