[76Alfasud5M]

I'm in the process of rebuilding the entire brake system on my Series 1 'Sud berlina and I am now down to the last part: the Rear Brake Bias valve. As you can see from the included pics, it is a mess and needs a rebuild. The rubber band that is supposed to be mounted across the rear axle was also missing.

I have heard about Alfasud owners switching this part out for an adjustable rear brake bias valve, possibly off a mini. Does anyone have any experience changing this part? Or is it better to go with the original setup and just rebuild it? And where can I find new parts for the original Rear Brake Bias valve?

Got any suggestions?

 

[77SudTi]

Id say just rebuild it, it works for the braking system you have and trying to adapt something else may cause hassles. By the looks of it, it doesnt seem to complicated and those seals are probably standard parts available from a brake specialist. If mine starts leaking I think I'll go for the rebuild.

 

[lenus]

When I rebuilt my Ti, I noticed somebody must have taken the bias valve out previously.

I never bothered putting it back in, it doesn't really seem to affect it at all.

 

[fly33boxer]

They do sweet FA, just put a bias valve in and if you worried about legalities you can put it in the engine bay

 

[Spooty22]

The Bendix part number for the original bias valve is: 312029B

There is nothing wrong with installing an aftermarket brake bias valve. You need to adjust it manually however, to ensure the rear wheels don't lock before the fronts.

BTW I have NEVER seen a sud that still has the rubber band over the panhard rod. They all perish away. I don't think it's terribly important anyway.

 

[lenus]

IS THERE SUPPOSED TO BE A RUBBER BAND HOLDING THAT THING ON.

I thought it looked odd.

My first sud had the rubberband...

 

[Sud1983]

I just removed mine and used a bias valve from a mini, which I mounted up front under the bonnet. If you replacing the lot makes sense not to bother with the Alfa one as is always gonna keep being a problem. The mini bias valve I've had on for 4 years and not a single problem so far.

 

[76Alfasud5M]

Does anyone know if replacing the rear brake bias valve by installing an adjustable one near the master cylinder will cause any problems with rear braking if the back axle starts hopping around on the pavement? The original bias valve on the 'Sud has the ability to adjust pressure as the axle moves up and down. If you install a "Mini" style version near the master cylinder, how will it know to adjust the bias if the rear axle starts jumping?

Also, will this Wilwood knob-adjustable part work?

Wilwood Engineering - Proportioning Valves

It mentions a maximum pressure reduction of 57%. Will that work for the 'Sud?

 

[Sud1983]

yes your right in that the original one trys to compensate when the wheels are off the ground and installing any other bias valve will lose that ability but to be honest unless you regularly manage to get your Sud up on 3 wheels I wouldn't worry about it. The rears on the Sud do very little anyway.

Yes that would work fine.

 

[76Alfasud5M]

Do I necessarily need the Mini bias valve? Or will the Wilwood bias valve work as well, or better?

 

[Sud1983]

No you can use any, be it the mini one, the wilwood one, an AP one, etc. They all work the same. I just used the mini one was it was the cheapest.