Rear Brake Lockup

[Guest Kev H]

Can anyone throw any light on this problem.

On my 2B+ the rear brakes are locking before the front. I have used the brakes from the donor 1.8 sierra. ie disks front, drum rear.

I have fitted the sierra brake compensator with no positive results.

At present even when the compensator is adjusted to almost horizontal, the rears still lock up.

My theory is that the the master cylinder piston which operates the front brakes is leaking through to the piston which operates the rear brakes. This is exerting more brake force to the rear and less to the front. There are no leaks but if the above is true then I don't think there would be.

My only other thought is that the valve is fitted on the opposite side of the car to that on the sierra. So in effect it is upside down, its still connected the correct way ie small end to the front and to the master cylinder. If the internal workings are symetrical then this will not matter but I'm not sure if they are.

Any suggestions anyone.

 

Kev

[Les Welsher]

Kev,

you've got the pipes connected the wrong way around, the pipe from the master cylinder goes in the back (thicker end) and the pipe to the rear brakes comes out of the front (smaller end)

Theory being that when you brake hard, the ball bearing inside the valve shoots forwards towards the the front (smaller end) and blocks off most of the fluid going to the rear brakes.

 

Les

[Guest Guy]

I did the same thing, I fitted the valve at the same angle and the same direction as it had been in the Sierra. Then I plumbed the break line through the valve to the rear brakes, as it looked the natural thing to do. When I went to one of the shows and saw everyone elses, I realised my mestake.

 

I had to re-plumb it so the pipe goes from the master cylinder passed the valve and into the fat end. Then out of the thin end passed the valve again and off to the rear brake shoes.

 

I had to extend the long brake line with another lenkth of pipe, so I've got a coupling in it, I had to use a 'brake pipe flairing kit' that I bought from Wilco for £20 to make the ends (well worth it's money).

[Guest Ant]

This picture may help. It is of the "later type" compensator valve, as fitted in the Sierra. The pipe at the front is going out to the rear brakes. The pipe at the back is coming in from the master cylinder. This is mounted as shown, on the near side of the Sierra body.

 

I believe it is symetrical inside so it can be fitted to either side of hte car, but the pipes are not interchangable.

 

One more thought - I can't work it out from what you've written, but are the pipes on the master cylinder in the correct places? The one nearest the servo goes to the rear, and other two go to the front.

 

Ant

[Guest Kev H]

Thanks everyone, that should sort it.

I will make up some new pipes this weekend

Thanks again

 

Kev

[Guest Tim Norman]

Kev now that you've seen how helpful we are how about joining the owners club and really getting the benefit

 

Cheers

Tim

Membership_form2.pdf

[Guest Angel Boy]

Kev now that you've seen how helpful we are how about joining the owners club and really getting the benefit

 

Top marks that man. 10 out of ten for effort as well.

 

Andy