[clive.allcorn]

Sorry if this has been discussed before.

Our livestock trailer is missing the gaiter on the tow hitch though I don’t think that is the issue. Whenever I attempt to reverse it the brakes lock. I presume this is because of the overrun mechanism on the brakes but as I don’t know how this is overridden when reversing, I have no idea where the problem might lie.

It is an HU3HE coupling which will cost me over £300 to replace so I’m hoping there is a cheaper fix!

[Buttermilk]

Do you have an auto reverse hitch or a manual reverse one?  If auto reverse it sounds like it has siezed or if it is a manual on there should be a bit of metal which flips over to stop the brakes coming on for reversing and then take it off for driving away.  If this is missing you can improvise.

[Womble]

I'd have thought it's very unlikely to be the coupling (at least in an unrepairable sense). The brakes work normally because the trailer tries to overtake the car when the car is slowing down. That pushes in the piston on the hitch, and activates the brakes.


However, reversing the car also pushes on that piston, and would normally activate the brakes (and it sounds as though that's the case for you here Clive). As Buttermilk says, there are two types of mechanism to prevent this from happening - manual and automatic. The first thing to do would be to find out if it's manual or automatic, and then go from there.


Another thing you can do - If it's a four-wheel trailer, get a ramp or a piece of wood, then drive up onto it with the "other" wheel so that each wheel in turn is lifted off the ground. Then rotate the now airborne wheel forwards and backwards by hand. If it will rotate freely both ways when the hitch piston is in the "out" position, next try compressing the hitch piston using a rope or strap and see what happens. The wheel should now brake forward rotation, but then the brake should unlock to allow backward rotation.

Perhaps try that and report back?

[chrismahon]

We had this problem 3 years ago with our IW trailer. If the slope is too steep ie. not flat, it takes a hell of a push to override the brakes. The solution was to fit a piece of metal into the coupling in the slot below the handle to stop the brake being applied. Don't forget to take it out afterwards! IW quoted £30 plus postage to France for their gadget, if I remember correctly, so I made one.

[twizzel]

We had this problem 3 years ago with our IW trailer. If the slope is too steep ie. not flat, it takes a hell of a push to override the brakes. The solution was to fit a piece of metal into the coupling in the slot below the handle to stop the brake being applied. Don't forget to take it out afterwards! IW quoted £30 plus postage to France for their gadget, if I remember correctly, so I made one.

We’ve done the same on a box trailer (not ifor). Essentially drilled a hole and put a bolt in when I want to reverse. Take it out before you drive off    but it works a treat.

[clive.allcorn]

Thanks all. It is the automatic type. The piston moves freely seemingly all the way in, at which stage the brakes are locked. How does a hard push override this? Is it possibly an adjustment issue at the wheel?

[Womble]

How does a hard push override this?

It doesn't!

Is it possibly an adjustment issue at the wheel?

Spot on!

Auto-reverse is a feature of the shoes and has nothing to do with the coupling. The brake shoes (or is it only one of them? not sure) are mounted on a spring-loaded slide, so while it brakes normally going forwards, when you reverse, the shoe rotates backwards and slips out of the way up the slide, which releases them.

I'll bet it's just this mechanism that's corroded and is stopping the brakes from releasing when you reverse. Any decent auto mechanic should be able to fix that for you at reasonable cost.

[clive.allcorn]

Thanks Womble. That is really helpful.