brown7373

Some time back I posted an "Oil Fouled Plug" thread. I have been putting up with the rough idle, while being too busy on another project to devote enough time to fix it. Off idle it seemed fine, so I drove it.


But then I realized my power disk brakes were not as good as they should be. Regular stopping was fine, but a hard stop was not, as I discovered I had a leak in the booster. I called Steve Gregori who replated and rebuilt the booster back in 2006. And how is this for GREAT SERVICE! He said if he didn't have to replate it, he would replace a leaking diaphragm AT NO COST! I said, "maybe you didn't hear me, but the booster is 10 years old" He said no problem, he'd still fix for free. Talk about a vendor who stands behind his product. Anyway, he said before I sent it back, to check to make sure the small rubber seal between the booster and the master cylinder wasn't damaged. Sure enough, that was the problem the whole time. And I just happened to have a good seal on an old booster that I never returned for core. I cleaned the booster, greased the seal with silicone and reinstalled, and the car idles fine and the brakes work properly again.


If you have a rough idle and/or a suspected vacuum leak, check both the booster AND the seal behind the master cylinder.

66luvr

Well, I learned something today.
I thought the rubber thing/gasket was there to prevent brake fluid from going into the booster if/when the master cylinder began leaking. I had no idea it had anything to do with vacuum.
It's a good day when I learn something I actually appreciate knowing, Thanks.

brown7373

I didn't know that either, Mike, and was happy when it fixed my engine. I was beginning to think I had a much more serious internal engine problem.