Brake Experts I have a question

[Lazydog]

I have a 1978 GMC Jimmy. My question concerns the proportioning valve. It looks like there is a 1 1/2 inch fitting between the valve and the brake line to the rear brakes. That fitting is leaking. It actually looks like there is a blowout valve on the side up against the frame. The dealer parts guy said these things do leak over time. Is that right? The new valve is $90.00 so I thought I'd get a second opinion before purchasing.

Thanks

 

[dyeager535]

Never seen, nor heard of, a leaky prop valve until your post. Heres a pic and short write up, if it helps you:

http://www.dorianyeager.com/combovalve.html

 

[79Beast]

Sounds like a junkyard part is needed. I've never seen one leak before. I have one I'll sell you for $10 off of a 74 Blazer. Also, it's a splitter block...not a proportioning valve. It should be mounted on the crossmember in front of the engine.