Trailer exhaust brakes???

From the fuzzy pic's there is a hose that runs to the hitch area of the trailer but it is thick like 1inch at most and def bigger than 1/2 inch it has some sort of connector at one end - maybe bayonet - maybe screw can't tell. the boat I think is about to or has clelebrated her 21st birthday.

I'm hoping that if it's vacuum assist they will still work without being hooked up..

I know, I know no point in wishing LOL.

Cheers

Sam

Vacuam brakes will definately not work without being hooked up, they are an ancient system, get a set of electric hubs and backing plates and change it over,

Not sure about this, but I was under the impression that the old style vacuum brakes locked the trailer brakes on and required vacuum to release them?

The idea being that if the vacuum source was lost (eg tow vehicle engine stopped, hose leak, fitting disconnected) the brakes were applied to stop trailer runaway as much as possible.

Vacuum trailer brakes were the best and probably still are. There are two ways to set them up, one is the single vacuum line which operates the servo on the trailer on its own, and the double line system, one of which controls the servo and the other which evacuates a vacuum reservoir to supply the power to the servo. Of course it is atmospheric pressure that does all the work. The trailer servo operates a normal hydraulic brake system.
The system on the vehicle has to be plumbed into the hydraulics of the vehicle brake system, usually the rear brakes. There is also a vacuum reservoir under the bonnet, and controller fitted to the dash It is similar to a pull out handbrake and indexes clockwise to adjust the braking force and pulls outwards to apply the brakes independently of the vehicle.
They were made by Repco I think and if they were still available that is what I would be using.
As for your problem RosscoH is probably on the right track.
Doug

Thanks for your thoughts and memories, it is a bit of a lost art!

Apparently the trailer can still be moved etc without the exhaust hooked up. No mention of if the brakes will still work at all...

I did have a friend send me this IP Add.

http://www.pbr.com.au/products/heavy/vacuum.shtml

which you may find as interesting as i did.

From what I can see I think then that Douglas might of hit the mark. There is a hydraulic automatic system ie, pressure from the trailer weight pushing on the hitch and then applying the brakes and a 2ndry system so that the brakes can be applied independently of the tow vehicle or at a different rate.

It would seem to me to be the most logical setup because
A. If the tow vehicle lost power the brakes wouldn't work, (ooooh sh......)
B. If the trailer has to be hooked up to a tow vehicle to unlock the brakes you would never be able to move it in a hardstand area for instance.

Please ping me back if I have got this confused.

Thanks Brains Trust : )
I got onto the previous/previous owner who never used it either...

"pressure from the trailer weight pushing on the hitch and then applying the brakes" describes the overrider trailer brake system and may be installed alongside the vacuum brake system but can not be used with the vacuum system, it is either one or the other. The vacuum system is controlled by the hydraulic pressure in the towing vehicle brake system and the setting on the hand controller.
According to the website you referred me to there are two set-ups, a breakaway system ie... if the trailer comes off the vehicle the brakes come on, and the type that doesn't. You would need to look up the legislation to find out which type you need but I would suggest that you may not need the breakaway type on a camper or caravan. Trailers with the breakaway system cannot be manoeuvred when not connected to the vehicle with the engine running unless the brakes can held off by another means. There would have to be a way to do this but I have been out of the industry for a long time and am not up with the latest developments.
Thanks for the link, I made the assumption that because of the prevalence of electric bakes vacuum brakes were no longer made. Guess what sort of brakes my next trailer will have?
Doug MacLennan

Well Doug it seems to me that you found an old friend in the vacuum system. So I'm guessing PBR or Repco will be getting a call?

As for moving a vacuum braked vehicle the pdf brochure has this jobby -

Used in conjunction
with a PV48A. When
the trailer is
disconnected from the
towing vehicle, the
action of the pv48a will
apply the brake. The
PV104 Dumping Valve
will release the brakes
by destroying the
Vacuum allowing the
trailer to be moved.

The Dump valave looks like it is just a plug that you pull to release the vacuum.

So with the vacuum setup you have adjustable braking, independent braking and emergency braking -- if the trailer becomes detached -- If you fit all the handcontrols and valves.

Douglas I am a complete novice so why is this preferable to electric brakes? Or did I take your post the wrong way?

RosscoH recommends dumping them.

---------

As far as I can tell so far it would appear the unit I am interested in the vacuum is alongside the override system because nobody has used it BUT the trailer has done interstate runs. It's @2.25t boat and trailer and the previous owners wouldn't do trips like that without any brakes. They were all very responsible crew. So the vacuum adjustability etc must be a bonus if you choose to set it up.

Less hazy on this now..

Regards,

Sam.

Time to "fess Up" that I don't know a lot about the latest trailer braking systems. I believe that electric brakes can be set up to have all the functions of a vacuum system including the "breakaway" but I believe you need to have a battery in the trailer to activate the brakes once the breakaway is triggered. In other words they can be set up so that there are no differences in function.
I have fitted both types (Not the breakaway type) in the early seventies and electric was considered pretty trashy (at the workshop I was in) when compared to the vacuum systems that we were installing. No doubt the situation has improved since then. Electric brakes are much easier to install in the vehicle because there is only the location of the controller and a bit of wiring to worry about. The vacuum brakes need the controller to be plumbed into the vacuum supply (inlet manifold on petrol vehicles),the brake hydraulic system, a vacuum reservoir(which needs to be fitted somewhere), and the vacuum line (probably 1/2-3/4 vacuum hose)to the rear of the vehicle. Also the hand controller needs to be connected via a bowden cable.
On the trailer the wiring on the electric brakes just goes directly to the brakes. The vacuum system needs a controller which is connected to a normal hydraulic system and to the vacuum line on the back of the car.
I suspect that even if you were able to fit a vacuum system yourself the cost may be prohibitive. It would be a good days work for a mechanic who knows what he is doing just to do the car.
Electric brakes work by energising an electromagnet which then drags on the flat part of the inside of the drum and hence forces the lever to which it is attached to apply the brake. The dragging magnet part is the bit I don't like but they appear to work OK as long as you keep the brakes adjusted (as you would on any brake) and keep an eye on your magnets. Apparently they wear out although mine haven't yet after 15,000 Kilometres. A breakaway system needs additional bits and needs to be explained by someone who has had experience with them (ie...... not me)
Getting back to your problem, your boat trailer probably has hydraulic drum or disk brakes which are connected to the vacuum activated controller. If this is so I would do one of the following
1/ Check the legislation in relation to vehicle/trailer weight and see if an overrider type brake is OK and have that fitted if it is not there already.
2/ Fit a vacuum system to your vehicle (expensive)
3/ Have your trailer brakes converted to electric and the controller fitted to your car(also expensive)
4/ Take the rig to a brake specialist and tell them to make it legal (possibly very expensive)
I hope this helps and that I haven't confused you.
Doug

Cheers Doug you have put it very succinctly.

I just really hope that the override system is operable and not too aged.

We really just need the trailer to get the boat home interstate.

I will check out the legislations in Vic and Nt and Qld and hope it pans out. We work in the NT are homebased in Qld but buying from Vic.

You know when people say"what a surprise to see you it's such a small world" I don't think they ever lived in Australia LOL

Thanks for your help Doug.

Cheers,

Slammin.