Non-Activating Surge Brakes

I have the standard Mastercraft trailer typically sold with most of their boats. For the purpose of knowing its size I will note that my boat is a 1999 Mastercraft 205 X-Star -- first year of the X-Star. My surge brakes recently stopped activating. I take classes at Austin Community College in the Automotive Technology department and we have confirmed that the core mechanical components of the brake system seem to be functioning normally, and my disc brakes and pads are in normal operating condition. Of note, my trailer came with the "surge brake deactivation" feature that taps a power lead from the reverse lights of the towing vehicle and prevents the surge brakes from operating when the vehicle is in reverse. IS IT POSSIBLE THAT THE SOLENOID/WHATEVER HAS GONE BAD AND IS STUCK IN THE "BRAKES OFF" POSITION? If not, what other explanation is there? I have also attempted to back my trailer while the lights/brake lead were not connected to my truck hoping the surge brakes would lock up when there was no power to this device, but no luck. Please help.

PS: I know this is not a case of the calipers insufficiently applying force, as the ongoing amount of rust buildup on my discs confirms they haven't been touched by a brake pad in months! Also, I popped open the brake reservoir and watched the device physically operate when I pushed and pulled on the trailer tongue, so again I am pretty confident that the master cylinder is not the problem.

[2000XPSD]

it sounds like rust is in the the line...check the orifice hole right after the master....it's very small and likes to plug up
you can also crack the line after the master and op it by hand and see if you get fluid

[93Prostar190]

Well what happens if you jack up one side of the trailer and spin the wheel by hand ..... get it going and then manually activate the brakes using a screw driver .... does the wheel stop? if the brakes and lines are working well it should ....

I can do this test, but how do I manually activate the brakes using a screwdriver?

[cbryan70]

pull the acuator back towards the boat.

[93Prostar190]

On most trailers ... if you look under the trailer tongue, you should see an opening when the piston that is in front of the master cylinder is visible. If you use a flat head screw driver you can push the piston towards the rear of the trailer (away from the tow vehicle) which simulates the same effect of the tow vehicle slowing down and pushing the coupler in that direction to activate the brakes.

the trailer coupler pushes on the same piston that you are about to push on. it should be easy to activate with with a screwdriver.

Other things to check ... is the coupler frozen or does it move backwards when you push it into the trailer ... a frozen coupler would not push on the piston/master cylinder and prevent braking as well.

[93Prostar190]

I also read your post again and noticed that you said the coupler moves ... which is good .... you should be able to stop the wheel that is spinning the same way.

Originally Posted by 93Prostar190

On most trailers ... if you look under the trailer tongue, you should see an opening when the piston that is in front of the master cylinder is visible. If you use a flat head screw driver you can push the piston towards the rear of the trailer (away from the tow vehicle) which simulates the same effect of the tow vehicle slowing down and pushing the coupler in that direction to activate the brakes.

the trailer coupler pushes on the same piston that you are about to push on. it should be easy to activate with with a screwdriver.

Other things to check ... is the coupler frozen or does it move backwards when you push it into the trailer ... a frozen coupler would not push on the piston/master cylinder and prevent braking as well.

The coupler is not frozen and moves appropriately. However, this entire section of the hitch is fully enclosed. The master cylinder itself is not visible to me except via the brake fluid fill hole on the top, and when I open the detachable trailer tongue and swing it away so I can look inside the tube where the rear-end of the master cylinder is. However, I can't actually see much of the master cylinder, as the device I mentioned earlier (the thing which is supposed to temporarily deactivate the surge brakes when the vehicle is put in reverse) is in the way (it is the first thing after the master cylinder).

[TMCNo1]

Originally Posted by juridicus

I can do this test, but how do I manually activate the brakes using a screwdriver?

It shows here in this UFP pdf on the actuator maintenance, http://www.ufpnet.com/Portals/0/PDFs...aintenance.pdf, page 25.

Originally Posted by TMCNo1

It shows here in this UFP pdf on the actuator maintenance, http://www.ufpnet.com/Portals/0/PDFs...aintenance.pdf, page 25.

Oh, this is a PDF I can use! Thanks so much for this... Let me see what I can find out now...