There are several threads different places about the break booster check valve being a common repair, and I'm experiencing several of the problems associated with this (vacuum pump doesn't turn off). So I went down to my not so local junkyard with a buddy and picked up a new (to me) check valve and vacuum pump for a whooping $5. One problem... my buddy horsed off the connector that holds the check valve spring in place and broke off the cap.

I do still have the spring retention cap on my old valve. The problem is that it will be difficult to get the old cap off. Anyone ever attempt this? Any lessons learned? I figure if I can push down on all four tabs around the cylinder and not pull at all on the cap, at the same time (nearly impossible?) that I might get the part off without damage. Trying to save $120 buying a new one online / from the dealer.

Anyone know where I might just be able to buy the cap that holds the spring only? I've searched and haven't had much luck. That's probably the best option.

 

I had to JB Weld mine back into position after it broke. Volvo uses very brittle plastic.

 

Hudini - thanks for the JB weld tip... I had thought of that, but wasn't sure if that kind of permanent solution is what I wanted. While talking to a coworker, I had an idea to use gasket sealer / RTV instead that way I could backtrack if I needed too.

Any tips on how to find the leak in the check valve so that I don't have to RTV the entire check valve? I thought about soapy water which works great in positively pressurized systems, but I'm not sure it will work so well on a vacuum system or that it's a good idea to put soapy water on the break vacuum line because soapy water can get in the line.

I'm pretty sure it's the check valve causing the problem because I hear hissing near the check valve after the car turns off and the vacuum pump turns off as well.

Thoughts?

 

A totally unsafe and non-politically correct method is to use an unlit propane torch. With the car running, open the valve slightly and place the nozzle near the suspected leak. The vacuum will suck in the propane and your idle will increase as the car burns the propane.

Try it at your own risk.