Leaking Bypass Valve Shaft??

Thomas A

Registered User
I tested my Cougar for vac leaks today by hooking up Ken's tester and pressurizing the system. I found a couple small areas of concerned and got those taken care of, but it seems the major leak I have right now is coming from the bypass valve shaft. It is leaking out of the inlet plenum around the area that the shaft goes into it. Has anyone experienced this before, and how would I go about fixing it? Is there some sort of seal in there? :confused:

Bypass_Vac_Leak.JPG


Thomas
 
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I had this too & it was not enough to be a problem. I did seal it with RTV ,after it was cured I cut around the shaft so it could slide & lubed it. This did stop the leak but it was no better for it. The most you could do is disassemble the valve off the car & replace the shaft bushing no thanks...
 
Looks like mine from the one on my 90. It leaks a little. I bet they all do. On the 95, it didn't show any signs of it leaking but I could only get 8psi through the system with the pressure tester I got from Spinning Wheels SC. I got an extra one from an 89, but I don't know if it leaks or not. As I'm looking at it, I think it could be repaired but is it worth a major PITA.
 
Before I had the Pressure Tester, I use a hose with a fitting and clamp on one of the fittings. If you don't have a compressor, I guess a bicycle pump would work but you might get a sore arm :rolleyes:.
 
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how to make a tester is in the FAQ read olny , you need a regaulater for a spray gun. will boost the system, soapy water will buble at the leaks
 
Mine is bad enough that you can hear and feel air coming out at 10psi. If I wiggle the shaft around, I can hear a change in the air flow, so it's leaking for sure, and seems to be leaking pretty good. I didn't really find any other places. I'm 3-4 short on the VAC side.

Thomas
 
The bore must be worn that the shaft goes through. I seem to recall that Magnum powers can fix that. Not sure of the mechanism there, but I would assume the center pin can somehow be extracted to disassemble the bypass.

Then you would need to put in a new seal and possibly drill oversize and press in a bushing that you then drill to the proper size.
 
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