Help me diagnose brake booster
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 6,097
Likes: 0
From: High Plains Drifter Fayetteville, AR
Help me diagnose brake booster
I know I've had a faulty brake booster for awhile now. Strange thing is, some days I'll have normal, strong power assist, some days I won't. Usually when I hit the brake pedal, I get a hiss and when I let off, the idle rpms will drop, the IAC will kick in and the idle will return to normal.
Now I just got back from a short cruise. While on the cruise I got a little too enthusiastic on my favorite off ramp, had to nail the brakes pretty hard for the yield at the end. So I hit the brakes hard, and hold for about 3 seconds. After about 2 seconds, my power brakes kicked in BIG time and I locked up the tires.
Is this a symptom of a faulty diaphragm, booster case, check valve, or what? I'm not very familiar with brake systems, so this one has me stumped.
Any suggestions? Was going to R&R the booster next weekend if I get the chance. Now I'm not so sure. :confused:
Now I just got back from a short cruise. While on the cruise I got a little too enthusiastic on my favorite off ramp, had to nail the brakes pretty hard for the yield at the end. So I hit the brakes hard, and hold for about 3 seconds. After about 2 seconds, my power brakes kicked in BIG time and I locked up the tires.
Is this a symptom of a faulty diaphragm, booster case, check valve, or what? I'm not very familiar with brake systems, so this one has me stumped.
Any suggestions? Was going to R&R the booster next weekend if I get the chance. Now I'm not so sure. :confused:
Le Mans Master
Joined: Jan 2002
Posts: 5,320
Likes: 4
From: Kyle TX (Because Mojo Made me fill it in)
Re: Help me diagnose brake booster (JCAIRE2)
Whats pretty much what mine did. The hissing sound you hear is vacuum leaking out from the booster. I suspected the diaphram went out on mine, but since I didnt take it apart, Im not 100% certain. Replace it and you'll be fine.
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 6,097
Likes: 0
From: High Plains Drifter Fayetteville, AR
Re: Help me diagnose brake booster (VetteNoob)
William, I know the diaphragm has a tear in it, I'm just trying to find out why I got a sudden surge of power assist when I was hard on the brake for 2 seconds. It REALLY came on strong. Gonna do it next weekend for sure. :cheers:
Le Mans Master
Joined: Jan 2002
Posts: 5,320
Likes: 4
From: Kyle TX (Because Mojo Made me fill it in)
Re: Help me diagnose brake booster (JCAIRE2)
I think it may be because after a while you get past the small tear in the diaphram and it seals back up. Mine was the exact same way until I drove it some more and stretched out the tear I guess.
