Brake bias/proportioning valve clean/rebuild

Can the brake proportioning valve be cleaned or rebuilt?

My rear brakes are working harder than the fronts and when the connector is plugged into the valve, the "brake failure" light is on.

Thanks

 

here ya go

https://www.ferrarichat.com/forum/threads/308-brake-failure-warning-valve.636293/

https://www.ferrarichat.com/forum/threads/308-brake-failure-light.324591/

 

Thanks!

I searched and searched but couldn't find anything on rebuilding it.

Thanks again!

 

no problem, I had a similar issue with the warning light coming on and rebuilt the valve

 

ragtop1,

How did you get the pistons out?

Thanks

 

I only had to replace the electrical switch part # 108955 and then crimped on a new spade connector from the original wire feed. I think it was about $30 for the part. It was a few years ago and it corrected the warning light issue.
I didn't remove the pistons, so I'll admit it wasn't a complete rebuild.
From the links above, some remarks state that they didn't have a problem removing the pistons, while others took the valve to a brake shop and needed a press to remove them.
I was fortunate that my problem went away by just replacing the switch and the pistons weren't seized.

If your Ferrari valve is seized beyond repair, perhaps purchase the replacement Volvo valve part # 1273052 (less than $100)
The OEM Ferrari is about $1400 - ouch!
Sorry I couldn't have been more help with the piston removal.

 

Thanks.

I pulled it out last night. Removed the cap and switch. the switch area was completely gunked up and the pistons are pushed towards the closed end of the body. I have it soaking in penetrating oil, but am not holding much faith that the pistons will free up. I'm going to try blowing the one out with air later.

As soon as I had it apart and saw it, I ordered the Volvo unit! LOL!

By the way, I believe the connector has been disconnected for years! When I rehabbed the suspension and steering rack, I noticed it disconnected. Connected it and the light came on.

Thanks again for your help!

 

The previous owner disconnected it to turn off the warning light. He wasn't as ambitious as you are to fix it properly.

 

Anyone know where to get those seals on the pistons?

 

You might have to source those seals and O rings out at an automotive outlet.

Image Unavailable, Please Login

 

absostone and I have this valve

 

I'll take a picture of the seal and numbers I was able to remove later today. Maybe that will help!

Since I have the Volvo valve coming anyway, I'm thinking of trying to drill out the closed end of the body and pressing out the pistons. Then tap and plug the hole.

 

when i had mine apart i ripped a seal on the piston, and cant find the dimensions

 

I'll get a picture and dimensions later today.

 

I asked Eurospares, but they don't have a rebuild kit. I'm going to keep asking other suppliers.

 

Problem I found was that none of the mcMaster or grainger O rings were thick enough. I thinner one will still work and have no ill affects on the braking, Mine is ripped and occasionally the brake warning comes on. No big deal

 

Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login

 

Image Unavailable, Please Login
this one. Please

 

Sorry...don't have that type.

 

what car do you have?

 

'77 GTB

 

Mine is like this one, strange yours is different. No pistons inside on yours

 

Mine is like the one in post #11 & #17

 

yup

 

I ordered one of the Volvo ones new from IPD and it was less the 70 bucks plus freight. If that fits it's not worth the project to rebuild one. I believe the one on my 76 is the style with two pistons.