Hyd trailer brakes not releasing

shane191, Apr 21, 2:37am
I took float for a 10k drive, got home and brakes were very hot (smoking lightly). Jacked float up and couldn't turn wheel. What are the causes of the brakes not releasing! thanks

franc123, Apr 21, 2:55am
siezed calipers/rusted pistons or caliper slides, or wheel cylinders, siezed master cylinder, siezed coupling slider.If its been a long time since they've had any attention its probably going to need a full overhaul, you need to be lubing the moving parts and flushing out the fluid regularly to avoid problems with trailer brakes.

tonyrockyhorror, Apr 21, 2:55am
Oops I didn't read the title very well!

As above.

intrade, Apr 21, 3:27am
probably seezed tow coupleing check the master cilinder most have a round tube sliding inside another and when you brake the trailer comes forward on the tube and presses against the master cilinder activating the brakes on trailer

shane191, Apr 21, 4:10am
They had been working ok a few months ago. Had a loose connection and lost fluid. a tightened it and bleed brakes thats when probs started.

skin1235, Apr 21, 4:24am
then as well as freeing up the piston seals you DO need to look at the actuator and the master, either one is restricting the movement and thus the return flow, or is stuffed and restricting the return flow, now you've stopped the artificial return ( that leak you had) the pads are heating the fluid behind the pistons and forcing them on even more cos the master is not allowing the expansion to go back through it

shane191, Apr 21, 5:43am
Just went out for another look at it and found i couldn't pull the handbrake on, pull the master cylinder off managed to free it up, now running smooth in and out (better than it has ever been) havent touched the calipers. there is a little bit of friction when spinning the hubs. - should there be any!

alan1111, Apr 21, 5:48am
A little bit is ok. Dont forget when actually towing the wheels are rotating and run out on rotors will push piston back.

skin1235, Apr 21, 5:52am
that maybe just temporary luck, or a permanent cure - till next time
to be on the cautious side I'd make sure I had a spanner that fits the bleeders on board for the next few times, at least if you feel it locking up or see smoke you can release the pressure and freewheel it home

skin1235, Apr 21, 5:53am
try backing it over a couple of bricks, then drive forward over the same, then back again,then jack the wheels and see if they still spin

shane191, Apr 22, 5:41am
Thanks everyone for your help. took it for a good run today. Brakes working fine and not heating up.

skin1235, Apr 22, 5:56am
did you try the back over a brick, that shows you if they are indeed working, otherwise good luck, hope all that was wrong was the front end

shane191, Apr 22, 8:47am
no didnt try the brick test, took it down shingle road and jumped on brakes, float brakes almost locked up.

skin1235, Apr 22, 10:00am
so they do work to some extent, try just backing up harshly, they should lock totally, may need another bleed

illusion_, Apr 22, 9:30pm
change the fluid