AR Inter Brakes

I have a AR110 & I'm hoping somone has some ideas on this, I have just stripped the wheels on the chassis and the brake slave cyl. are stuffed. > > I have got a VH44 Booster to put on it but I am wondering if it's possible to change the single sided slave cyl to a dual action one the same as what's on the rear. I'm guessing I would have better? brakes? or am I wrong?
all thoughts / ideas appreciated
Cheers
Gary

Gary, I'm not sure if the same applies to your truck but I've been told by a PBR dealer, the PBR booster I need for my AT4 Dodge w/- 4 drums, is a VH40D, this model has a large fluid cylinder to feed enough fluid to the wheel cylinders. They told me the VH44 is for a disc front/drum rear vehicle??
Best check with your local brake specialist to make sure.
When you think how much the front discs move compared to a brake shoe you might find your wheel cylinders are starving for fluid, disc pads are virtually only a couple of thou from the discs whereas shoes can be a couple of millimeters off the drum surface, so a lot more fluid is needed to move the shoes that far.
Better to be safe than wrapped around a tree.
Not sure what you mean by single sided slaves, do you mean the wheel cylinders only push one shoe ??

Tony, SA

Thanks Tony, will check. Yep front cyls only move the front shoe and rears move both.
Gary

Gary, Call in and see Bob at Midlands, he will know what will interchange and what will work...

keep at him and the prices tend to drop a bit

the bloke at the brake place in Lily street seems to do a few old trucks... he might have some idea too....

good luck

/me

Gary - I'm hazarding an educated guess here .. but I would say that the IH engineers designed the AR-110 front brakes with just a single piston wheel cylinder, to ensure more even application of brakes, as compared to the two-piston, rear wheel cylinders.

Your front brakes shoes would have what is known as "floating shoes". This means that when brake fluid pressure is applied, both shoes can move freely to centre in the drum .. and the pressure is evenly applied to both shoes.

With the rear setup, each of the shoes pivot on one end, with the other ends each having pressure applied from the pistons. This setup can have variations in pressure applied to each shoe, according to wear, corrosion, and friction in the shoe and adjusting mechanisms. This can result in one wheel braking slightly harder than the other.

In the old days (when I was still a young adult!) .. all cars and trucks, only had drum brakes. They were a pretty awful braking system .. and not only was a great deal of pressure needed to get a vehicle to stop .. but pulling from one side to the other, particularly on the front, was a constant problem.

Thus, when you did a heavy-braking stop, you nearly always had to steer in one direction against brake pull. This wasn't an isolated problem, it was common with virtually all drum-braked cars and light trucks .. and it got worse as they got older.

I would say that the IH engineers designed the front brakes on the AR-110, to try and reduce the brake pulling problem.
If the rear brakes have an imbalance in braking effect, the pulling effect is barely noticeable .. however, if the front brakes have a braking imbalance .. the brake pull effect is very noticeable.

Re the VH40/VH44 power booster. These boosters are an excellent addition to any drum-braked vehicle. They reduce the required brake pedal effort noticeably, and they improve braking distance substantially.
I used to fit them to all my early Holdens, before the first disc brakes became available on the HR Holden. They improved Holdens notorious, "go-faster" drum brakes, out of sight.

The brake man that Thunders-Truk spoke to, knows his VH series boosters. There are no less than TWENTY ONE models of VH40 and VH44 brake boosters .. each designed for a specific setup.
The major difference between the VH 40 and VH44 is in the bore size of the "slave" cylinder on the booster.

There are SIX models of VH40 booster, with slave cylinder bore diameters varying from .5625" .. to .625" .. to .875". The most common bore size is .625".

The VH44 has FIFTEEN models, with slave cylinder bore diameters ranging from .625" .. to .750" .. to .875". The most common bore size in the VH44 is .750".

These variations, along with booster size variations (length of stroke, and diameter of booster diaphragm) means that the output pressure of the VH40/VH44 models can vary from 820 psi to 1470 psi.
Along with these pressure figures there are sizeable variations in the amount of brake fluid displaced. Thus, you have to match your VH model of booster to your braking system.
The VH40 produces the highest pressure, but the VH44 produces the biggest volume of fluid displacement.

I have an original copy of the VH40/VH44 manual if you want a reproduction of it. This manual comprises 22 pages, and is very comprehensive.
It covers design, specifications, installation, overhaul, maintenance, parts list, and troubleshooting.
All the specs are provided in massive detail. It's absolute gold, all this info .. these manuals are very hard to come by, and are highly sought after.

The VH series boosters are very popular .. even old, knackered ones bring $60 or $80, and sellers ask around $250-$300 for overhauled ones.

Cheers - Ron.

Thank for that Ron, if you don't mind I will take up up on that offer just let me know how much
Cheers
Gary

G'day Gary - A copy of the VH40/VH44 manual will set you back $10, incl postage. I'll send you a PM with further details.

Cheers - Ron.

all correct ron the correct term for dual piston wheel cylenders is duo servo and the single piston is single servo when you adjust your brakes by ocasionaly pumping the pedal it allows the shoes to centralise giving better adjustment also if youadjust the shoes until the wheel locks then back the adjusters off enough to stop the shoes from dragging . if you back the adjuster off six notches back them all of six this could be any number of notches 5; 6 ; 7 ; 8 ;but you will find out when you adjust the first shoe and back it off. getting a bit more technical with a booster they are all diferent applications so the correct one is critical the lengthov the bore and diameter will determine the amount of fluid that comes out and if undersize the booster piston will reach the end of its stroke the brake pedal will become hard yet the brakes have not expanded enough to work so pumping the pedal is the only way you can stop especialy when the brakes are out of adjustment hope this helps don

Damn Bu@@er Blast!!!!! >:( >:( >:(
Took the front (5 stud) brake drums into town today (thanks Sarge) only to be told they were too far gone to make legal so now I need to find a pair ,:-[cheap :-[ , that I can make roadworthy,any leads etc appreciated.
Cheers Gary

Gary, there were some on ebay. Can't remember the price. Have you removed the back ones yet? Keep in mind these are tapered axles like early Holdens. I have heard of a few blokes on the oldihc.org in the USA smash their drums by hitting to remove. :'(Apparently very rare in the US of A. I made a puller jig out of a Valiant wheel. Dave