Rear Brake Bias - Manual Adjuster

[jbo]

Hi All,

I'm running a rear mk4 golf gti brake setup which has way to much power to the back. This is unfortunately what caused me to write my car off after hitting the brakes too hard and losing the back end! Hence my reshell thread!

The rear axle does not have the original load balancers fitted so I need to install a manual bias valve. At the moment I am running a four port servo; one for each wheel. I am looking at buying one of these as I like the fact the it only bias mainly under a heavy load.

A few questions -

- Can install just the one? IE Block one outlet port and run a t piece from the bias valve to the rear brakes?

- If I run the rears on a single circuit should I do the same with the front? Issues with diagonal braking across both circuits?

- Or should I just for out for two bias valves?

Any thoughts would be much appreciated. I don't want to rebuild the car from scratch to write it off from the same fault!

Jason

[marcus]

What were you thinking putting the rear brakes from a heavier car on a lighter car? :)

[bengould]

I'd say you'd be better off running 2 valves and keeping the diagonal split, that way you still have some braking I'd part of the cylinder fails.

Ben.

[james butler]

Would it not be possible to modify a standard brake bias valve to fit and nut and bolt the adjuster so you can tweak it then lock it up when your happy.
Ultimately though it should vary depending on the load you put in the car. So you may have trouble getting it through an mot if you set it too weak.

[jbo]

Cheers guys. I went with the two hand lever valves in the end. You can change the angle of the levers so shouldn't have any issue with mounting them below the master cylinder. I will only ever really be having a max of one extra person in the car.

Jason

[dozzum]

Which ones did you buy and how have you found them?

[jbo]

I went with these ones matey -

http://www.ebay.co.uk/itm/BRAKE-BIAS-VA ... 41690ed920

Lol I have not had a chance to test yet! They fitted in well enough and feel pretty solid. I've mounted mine below the coolant bottle.

Jason

[dozzum]

Cheers. What brakes have you got on the front?

[jbo]

280mm G60s at the moment. They now run on a 22mm servo setup.

Cheers
Jason

[dozzum]

And the backs still outbrake them!!!

Im definitely going to need a bias valve then as I'm putting circa 2000 polo/seat brakes on the back and 256 vectra callipers on the front.

Did you look into just using a non adjustable valve like one out of a mk2 golf?

[jbo]

Lol only when I slammed them on at high speed. I do have Mk4 GTi discs on the rear though. You definitely definitely need to control the split! The car as standard has a proportioning valve in the rear axle. I didnt want to retro fit this (mine is gone) and keep adjusting all the time. I can trial and error for the load (me and a passenger) and leave it there.

Cheers
Jason

[dozzum]

I don't think mine has the valve on the rear axle as it's an early one. Haven't actually checked yet but I dont remember seeing it.

[jbo]

Ahh ok. You can fit them but they are damn fiddily to set. I'm don't think they will work as standard with rear discs....maybe someone else can confirm or not.

Don't forget the lines in the car are stell not copped. If you go with bias valves you'll need to cut the lines back slightly and flare some ends. Steel is really hard to flare so i ended up taking it to my local garage. The ends looked ok but i still need to bleed my system before I can really test them. If they leak then ill need to change all the lines for copper. Grrrr....