Brake Bias Box

[Guest shredmaster73]

Hi guys,

I've stripped my car out just leaving the carpet and two front seats so it's going to be very light at the back. As I've got to put new rear brake lines in I thought I may as well go for a brake bias box to stop the light rear end from locking up. I've seen these items for £60 - £70 but do you need any other bits to go with it ? Also, I want to keep the car road legal, will it pass an MOT with a bias box ?

 

Cheers, Lee

[Guest shredmaster73]

Hmmmm, shall I use my invisibility to fight crime or for evil ?????

[saveloy 8]

I don't believe it will be road legal. Apart from the pedal box itself,you will need master cylinders(2),reservoirs(2).

I vote crime.

[Guest shredmaster73]

I thought there must be something else, have to give that idea a miss then if it's not legal. Unless of course I can hide it away somewhere it won't be found on an MOT !

So why do you need 2 master cylinders and 2 reservoirs to make the bias box functionable ?

 

Cheers

[Swilki 0]

You don't, you just need to take a lump out of the back brake pipe and fit the valve in. Not sure if you'll need to remove the compensator though, or if it'll be road legal?

 

You need 2 master cylinders if you have a brake bias pedal box with a threaded bar which adjusts the proportions of the brake force. What you're suggesting, if i'm right, is just a little box with 2 brake line connections and a knob or lever on top to change the rear brake force.

[Guest Bigj]

You don't mention if its a 1.9 or a 1.6 ?

 

If its a 1.9 you will need to re-pipe the rear brakes to run on one feed from the front.

 

You will need two master cylinders, probably 0.625 for the front and 0.75 for the rear. You can probably go to 1.0 on the rear but you don't state which brake setup you are using. It may take a bit of trial and error to get it right.

 

 

If you are using just a brake bias valve then all it does is close down the rear brake line and limit the pressure to the rear brakes.

Either connect it after the existing inertia valve or fit a 10lb non-return valve adjacent to the Master cylinder.Otherwise you will have large brake pedal travel.

 

I'd fit some braided hose as well while you're at it.

 

Have fun

Edited December 10, 2003 by Bigj

[Guest Bigj]

Sorry I forgot to say

 

I have had ny car Mot'd with both a rear brake adjuster valve and a bias pedal box and have had no problems.

 

The bias pedal box is certainly legal, the valve could be a grey area.

But I have never had a problem in the last 20 years

 

HTH

[Guest shredmaster73]

Thanks Bigj & swilki,

It's the 1.9 I have, I've rebuilt all the calipers with new seals where appropriate, braided hoses, black diamond combi's & predator pads, I've left the rear discs standard.

I think I may be confusing myself with what I actually want. Basically what I want to do is replace the compensators with something I can alter. Maybe with the enhanced stopping power up front, that may balance out the over braking I'm expecting from the rear (as it's lighter at the back now ). However, I would like to be able to fine tune it just incase it still wants to lock up at the rear. So what's the difference between a rear brake adjuster valve and a bias box ?

Cheers, Lee

[Swilki 0]

what's the difference between a rear brake adjuster valve and a bias box ?

 

You said it yourself, the brake adjuster valve only controls how effective the rear brakes are. All you can do with it is reduce and increase the fluid flowing to the back. The front is the same as usual.

 

With a bias box you have a master cylinder for the front and another for the rear, with a rod to connect them so that by moving the adjusting screw towards the rear you are increasing the rear brake force AND reducing the front, where as with the valve you are only increasing the rear brake force, the front will be the same.

Edited December 31, 2003 by Swilki

[cybernck 400 1 Cars]

actually, that depends on how the brakes are connected onto the master cylinder sections.

 

speaking about standard setups here.