Trailer Brakes while parked backwards down hill

[skyhuck]

My trailer had not long been serviced, i reversed down my drive. I put a brick as 1 side( only had 1 brick kicking about) i kept the cable n and wound the jockey, once off it shot round to the 1 side, the cable horsed the brake until it was tight against the trailer and it hit my house. i had a pallet of turf on it.

well worth checking guys, if you have a spare bit of time try it.

 

The fact that the handbrake lever hit the trailer suggests the brakes needed adjusting.

[Stephen Blair]

The fact that the handbrake lever hit the trailer suggests the brakes needed adjusting.

 

I would say it was the result of the trailer shooting back 2 ft with over a ton on it and horsed the lever right back as the cable didnt break.

We often push the trailer about in driveways and car parks, when applying the handbreak while going backwards slowly, it will always stop.

From what i have just read, the trailer breaks will roll back 10" s before applying.

Fig 5 http://www.al-ko.co.uk/edit/files/handbooks/overrun-braking-system-handbook.pdf

[scotspine1]

If it is not possible to park the trailer with its nose facing downhill, all wheels should be chocked, with suitable purpose made chocks.

 

Dean, these purpose made chocks? are these ok?

 

 

 

[Dean Lofthouse]

Full braking force will never be achieved, once the auto reverse cam operates, the full surface of the shoes cannot contact the drum, only a small proportion. Yes the brakes will apply, but absolutely nowhere near 100%, I would say around 50% at a guess as the top section of the shoe has been drawn away from the drum, only the bottom section of the shoe where the cable enters contacts the shoe.

 

Its extremely irresponsible to try and convince people the brakes work in reverse and you can park your trailer either way round without problem.

 

I,ll say it again as a mechanical engineer with 35 years experience, specialising as a vehicle mechanic. If I,m proved wrong, I,ll hold my hand up no problem. I would never give false / ignorant advice trying to save face.

 

This time in bold

 

 

Trailers with auto reverse (including chippers) should, if possible be parked on a flat level surface. If the trailer has to be parked (unhitched) on an incline, it should be parked with its nose facing downhill.

 

If it is not possible to park the trailer with its nose facing downhill, all wheels should be chocked, with suitable purpose made chocks.

[Dean Lofthouse]

Tim....the top chock will do fine, but back it up with the second then the third

[Mark Bolam]

Where can you buy them Tim?

 

 

Sent from my iPhone using Arbtalk

[Dean Lofthouse]

I've had the handbrake pull itself on very hard, making it hard to remove, but not fail.

 

But this was a well maintained, nearly new caravan.

 

The dual axles on your caravan will be more than capable of a braking force for a 3.5t trailer, so even at 50% capacity in reverse, they will have no problem holding the weight of your caravan.

 

However, if they do hold, it may only take a slight nudge when hitching up to exceed their holding capacity (especially if in need of adjustment) and knock off the reverse cam, then your caravan may pee off on a holiday all of its own

[scraggs]

Full braking force will never be achieved, once the auto reverse cam operates, the full surface of the shoes cannot contact the drum, only a small proportion. Yes the brakes will apply, but absolutely nowhere near 100%, I would say around 50% at a guess as the top section of the shoe has been drawn away from the drum, only the bottom section of the shoe where the cable enters contacts the shoe.

 

Its extremely irresponsible to try and convince people the brakes work in reverse and you can park your trailer either way round without problem.

 

I,ll say it again as a mechanical engineer with 35 years experience, specialising as a vehicle mechanic. If I,m proved wrong, I,ll hold my hand up no problem. I would never give false / ignorant advice trying to save face.

 

[/b]

Just out of interest Dean

If you look at page 3 of this pdf, I can see how it could be possible to apply the front and rear shoe fully, which would explain why the handbrake pulls up more as the trailer rolls back ?

Or am I missing something ?

[Dean Lofthouse]

Yes it does apply but not at full efficiency. It brakes with the leading leading edge which in forward rotation is the trailing edge. The forward rotation trailing edge is normally square and leading edge chamfered. This is what will give a bit of a "grab" feeling when the brake is applied when rolling backwards a little. But the braking force is nowhere near as effective as it would be in forward motion. The pdf list you have shown is a sliding shoe system which is more efficient than the older systems and if serviced and adjusted regularly is a very effective system but should never be trusted with a loaded trailer backwards down a hill. A chipper (and im not talking about a sub 750kg baby) should be classed as a permanently loaded trailer

[Dean Lofthouse]

Just out of interest how many of you have serviced or even looked inside your chipper or trailer brake drums in the last 12 months or even ever adjusted them and i bet it isn't many. For these systems to work they need regular servicing which includes copper slipping r greasing the cam or slides on the auto reverse