trailer brakes

super6 · Post by **super6** » Tue Jan 13, 2009 4:55 pm

hi i have a 1972 13 ton tipping trailer that has hydraulic brakes,
they have not been connected for about 6 years, they do not bind and after taking one drum off they have loads of adjustment the trouble i have is i can just about get them to brake, but i am having troble getting them to release without the aid of a hammer.
which bits do i need to oil or clean.
this might seem obvious to you but i have never really looked into a drum brake before.

Grani · Post by **Grani** » Tue Jan 13, 2009 6:04 pm

The best thing to do is to take a picture of the brake so You can se afterwards how the parts was. Then take apart the brake and put all the parts in order on a table. Then clean the parts so that they move easy and smooth and look for defect parts and seals. Then put together with clean and intact parts.

Pascal · Post by **Pascal** » Tue Jan 13, 2009 6:21 pm

Hi Super6,

Do you have the trailer behind your SuperMajor? Do you have a hydraulic brakingsystem on this tractor?

I'm curious how that looks like and how that works.

super6 · Post by **super6** » Tue Jan 13, 2009 7:43 pm

normally i would not worry about brakes but this a big trailer 3 ton empty, so i will connect the trailer brake hose direct to spool valve so i can lift quadrant and brakes will be applied.
Not ideal but better than no brakes.

Post by **Brian** » Tue Jan 13, 2009 11:48 pm

Word of warning with my HSE hat on. Someone mentioned the words Super Major and 13 ton trailer or even 3 ton trailer unladen.

With a trailer that size you are possibly overloading the weight carrying capacity of the standard tyres with an empty trailer on the draw-bar. You will be exceeding the static load on the draw-bar certainly.

I would not like to advise fitting hydraulic brakes to a system where the hydraulic power can be disconnected by putting the PTO out of gear. All the modern systems used in trailer braking are fed from a totally live hydraulic system.

In the modern world, if you got pulled over by the DoT, the fines could be pretty enormous as they would be if anything happened that caused an investigation by the HSE even if not used on the road.

Now I have taken the HSE hat off.

If you have a spool valve, it may be that the oil flow back is not fast enough to release the brake. Would it be possible to fit a double acting ram that pushed the brake on and pulled the brake off using both sides of the spool valve.

super6 · Post by **super6** » Wed Jan 14, 2009 5:31 pm

hi Brian, hopfully my tyres will be ok as i have 38" radials off a county.
Brake system is a bit stange as the ram is like a bicycle pump and has a spring inside it, the ram then pushes a reservoir of fluid that actuates the brakes, just not sure how they release.
Only thing that would concern me is weight on the drawbar, would it be worth me having it shortened i have seen them on other majors where the jaw is closer to the piece of drawbar with all the holes.

Grani · Post by **Grani** » Wed Jan 14, 2009 5:45 pm

I would not use anything else than a hitch hook for that load. Here in Finland it is legal to tow a trailer that weights two times more than the tractor, so when a Major is 2300Kg the trailer has to be less than 4600Kg

Post by **Brian** » Wed Jan 14, 2009 6:30 pm

If you have 13.6x38 R tyres the load carrying capacity is 1925kg per tyre at 23 psi. That gives a total load on the axle of 3850 kg.

Your unladen trailer plus the tractors 40% load on two tyres comes to 4800 kg, so without any load on the trailer, you are 950kg over your limit.

If you fit 14..6x38 R tyres their load capacity at 20 psi is 4410kg so these would be around 400kg overloadedwith an empty trailer.

This has been a problem that a lo of people do not consider but the Dot is now starting to push it pretty hard.

Grani · Post by **Grani** » Wed Jan 14, 2009 7:28 pm

The owner of this Manuel was transporting concrete poles in the early 60:s with it. Now he has restored it. The trailer had hydraulic brakes and he told me that when he had to brake he had to shift to neutal and then activate the hydraulic output. The trailer had a boggie 3 axle system that lifted some axles up when emty. At at load of 7 tons all axles was down in touch with the road. I don´t know how mutch the whole load was. The poles was 25cm*25cm*18m long, and he drowe some times 300 km/day. The tyres did not last very long on gravel roads those days.
I met him at the Fordson-Club annual event Rauta ja Petrooli (Iron and Kerosene) last summer. He had a lot of intresting storys to tell.
http://gallery.kuukuna.net/albums/Fords ... _kuva1.jpg

super6 · Post by **super6** » Wed Jan 14, 2009 9:05 pm

obviously the trailer is approx 3 ton empty, but only a small percentage of this weight is actually on the drawbar as the rear axles are taking most of the weight, so tractor tyres will not have much weight on them.
as far as max weghts go in uk i think a modern tractor ie fastrac at 7 ton can tow a trailer upto 25 ton, so not sure how that relates to a major.
i am pretty certain there are no laws which relate to the weight of the towing vechile.

Tubal Cain · Post by **Tubal Cain** » Wed Jan 14, 2009 9:45 pm

It would appear there is some confusion between the nose weight of a trailer and its gross weight.

The nose weight is the static weight applied to the towing vehicle through the tow hitch, which depending on the number of axles on the trailer and the distribution of the load on the trailer will either produce a downward or upword force on a fixed drawbar. The effect on the tractor is influenced by the distance from the rear axle centres to the towing pin, in severe cases it can cause the front wheels to come off the ground, idealy this distance should be nil.

A twin axle trailer with turntable steering would exert minimum static loading on the towing vehicle, however the criteria is whether there is sufficient power to tow the trailer and more importantly once the load is moving whether or not the towing vehicle is capable of stopping the load.

Anyone who disputes this is quite welcome to come and observe my friend towing/shunting his 10 ton steam roller with his County! The only static weight on the tractor is part of the weight of the towing bar!

Gerald

Mike Kuscher · Post by **Mike Kuscher** » Thu Jan 15, 2009 12:18 am

Super6 wrote...

i am pretty certain there are no laws which relate to the weight of the towing vechile.

I'm afraid there most definately are!
I have been towing for years (caravans, horse trailers, etc.)
Over 10 years ago, our local police force organised a whole day Sunday event, free of charge, for advice and instruction on towing regulations and techniques. I only went, to be 'nosey' because it was 10 minutes walk from home.
It was sponsered by a couple of tow bar manufacturers, 4x4 manufacturers, Institute of advanced motorists, New Holland and NFU.
They arranged it because so many people/farmers had been prosecuted, over a 12 month period, for towing loads exceeding the permissible maximum for their vehicles and, following a survey by the police, they estimated over 50% of people towing were breaking the law through ignorance.

I attended for the day, out of interest.
It was well worth going, in fact, it was frightening !!!
I'd already been towing for over 30 years. I learnt a lot !!
Help, advice, classroom theory AND Practical Instruction was supplied, free of charge, including public roads and the M42, at no cost or obligation, with police and other professional instructors. One of the most useful and interesting days I've ever spent.

I would strongly advise some serious 'reading up' here.
Towing with the sort of weight ratios that are being talked about here are breaking two sets of laws. The first set it Road Traffic Act. the second is Use and Construction regulations for braked, unbraked and close coupled trailers.
Never mind the laws, what happens if (WHEN) something goes wrong?
Be it on your own head if you're caught.
The fines ARE BIG and above a given limit, include prison sentences as well.

Mike

Tubal Cain · Post by **Tubal Cain** » Thu Jan 15, 2009 11:37 am

Further to the above I came across this article which is rather sobering and I'm sure a similar situation exists here in Pembrokeshire at silage time.

http://www.roadtransport.com/Articles/2 ... e.html[url]

When you get to this site you need to type "Chips are down for agricultural haulage" in the search box and then click again on the heading.

Gerald.[/url]