Trailer auto reverse brake issue

AIUI, in reverse when the shoes touch the drum they move and are then retracted from the drum, it would seem that this mechanism is for some reason not working.

Chris

Chris J Dixon explained on 07/05/2018 :

They use the fact that the overun brake is under compression and the wheels are attempting to be be turned backward, to disengage the brake shoes.

If the overrun brake is under compression, but the wheels are rotating in the forward direction, then the brake shoes will work normally.

There is a full explanation here..

It's been a while so others may be more up to date or complete on this. Overrun brakes will do that if the spring stopping them acting is too weak, or if the car is jerked backward.

NT

All 4 hubs are locking on ... so unlikely all 4 springs went weak at same time ..... must be something common, I'll try resetting actuating rod.

last one I played with had 1 spring pushing the drawbar out, but it was a long time ago.

NT

Update on this ... Replaced the actuation rods,as the adjuster was corroded solid.

Set that up so correct clearances .... again brakes activating fine, handbrake holding fine - and in correct 90 degree position.

However auto-reverse still not working.

Anybody any clues.

show us a pic/diag of the mechanism

NT

I have not seen most of the replies, so I'm probably repeating some of them!

I'm assuming they are the same type as the Alko caravan brakes.

The brakes are supposed to initially lock-on after the damper/push rod is pushed in as this causes the trailer brakes to operate under normal braking conditions. However, when reversing, the brake shoes lock but then are partially released by the action of the brake drum assembly rotating.

For this to happen correctly the brake shoes and the push rod adjustments are critical.

We have a small caravan and there are times when it seems as if the brakes aren't going to release when starting to reverse onto a pitch.

Sam

It's as per the link posted by Harry

Decide to replace all 4 Bowden cables, lubricate the expander mechanisms and set up again as per manual.

Strange getting conflicting advice .... phoned 2 different Indespension dealers

Replaced all 4 cables ... checked adjustment again ... and still locks on when reversing up hill.

I looked at the reverse unlocking mechanis but didni't understand it. Do yo u?

NT

This any help?

I must admit the Alko diagrams are a bit rubbish at illustrating what actually goes on and the video perhaps doesn?t add much.

Tim