surge brakes locked on

[sly_karma]

Headed to the lake yesterday after another hot Okanagan day. At the marina I noticed brake smell and hubs were hot, enough to push some grease out the bearing buddies. Unhitched briefly and the trailer rolled easily. The brakes were not locked on anymore, but clearly they had been. On the way home I stopped after a kilometre and everything was fine, same when I got home (5 minute drive).

The trailer is a single axle 20' with surge activated drum brakes. Had a full rebuild on them a year ago, put about 2000 km on the trailer since then. I'm careful to re-grease bearings in spring and after a long trip. Never known the trailer to do this before. I did have to pull up fairly sharply for a stop light en route to the marina yesterday but nothing exceptional. Any idea what happened?

 

[SteelyDan]

Maybee crack the line from the main cylinder to relieve the pressure. Re bleed and try it again.

 

[spring fever]

One of the individual wheel cylinders stuck when the hard stop occurred-it didn't release. I might be tempted to pull that wheel and check the bearing and re-pack. If you don't want to do that -do a few reasonable stops-spin the wheels-check on the inside of the backing plate and watch for brake fluid. If dry monitor and really have a close look on the fall re-pack.

 

[sly_karma]

Both wheels had locked at some time in the recent past, they were both hot and pushing grease. So if anything stuck it would be the master cylinder or the surge actuator itself.

 

[high tide]

Both wheels had locked at some time in the recent past, they were both hot and pushing grease. So if anything stuck it would be the master cylinder or the surge actuator itself.

Thats what I'm thinking, likely the Master Plunge rod it's self stuck....... Hope you have success figuring it out.

 

[tykkyt e blue]

try 'bumping' the trailer coupler by going from drive to rev several times without actually moving the trailer - this compresses and releases the coupler and can move enough brake fluid to encourage the fluid to return to the coupler - your return springs at each wheel make be rusty/weak and are not compressing the wheel cylinder back to the 'off' position.
I try to pull ahead on coupler as last move with tow vehicle to make sure brakes are not left semi-applied as the trailer sits

 

[sly_karma]

Thanks, I'll try that if it happens again.

 

[Sir Reel]

That happened to me before and it turned out to be the Master cylinder. When you do a hard stop it jams and does not release back. Had to replace the whole unit.
When it does happen, as a temporary fix, you can loosen the brake line connector coming out of the master cylinder to release the pressure.
United hitch in Kelowna can get you parts or do the repairs.