Brake booster ?
Thread Starter
Pro
Joined: Jan 2009
Posts: 686
Likes: 4
From: Austin Texas
Brake booster ?
Seems like I've been riding my '93 on a lot of gravel lately, I go very very slow, but there's still been a lot of vibration applied to the vehicle recently.
Then yesterday, I went over a fairly smooth railroad track doing about 40 mph, and lost power assist on the brakes suddenly and without warning.
Its acting as though maybe the diaphragm inside the booster is ruptured ..... ? When I apply the brake pedal at idle, it makes a hissing sound from the footpad area, kinda sounds like something hydraulic down there, and I can hear engine idle increase, but only slightly although I suspect that's normal. If I let off the brakes, everything gets quiet again and engine speed drops slightly.
What I ponder is whether a hose, wire, etc. may have vibrated off its connection, before I go through all the fun of pulling the booster. There's no power assist on the brakes at all. Any ideas, wild or otherwise ? thanks alot
Then yesterday, I went over a fairly smooth railroad track doing about 40 mph, and lost power assist on the brakes suddenly and without warning.
Its acting as though maybe the diaphragm inside the booster is ruptured ..... ? When I apply the brake pedal at idle, it makes a hissing sound from the footpad area, kinda sounds like something hydraulic down there, and I can hear engine idle increase, but only slightly although I suspect that's normal. If I let off the brakes, everything gets quiet again and engine speed drops slightly.
What I ponder is whether a hose, wire, etc. may have vibrated off its connection, before I go through all the fun of pulling the booster. There's no power assist on the brakes at all. Any ideas, wild or otherwise ? thanks alot
Last edited by ChrisWhewell; Jan 16, 2012 at 04:58 PM.
Drifting
Joined: Jun 2010
Posts: 1,853
Likes: 8
From: Westerly RI
It sounds like either the diaphragm in the booster has failed, or the vacuum line from the plenum is leaking. Don't think gravel roads would affect your power brakes (might affect the paintwork, though).
Race Director
Joined: Apr 2003
Posts: 17,699
Likes: 1,667
From: moraga ca
Adapt a Mytivac vacuum pump to the diaphram and keep pumping. See if it will hold a vacuum. If it does, it must be a hose leaking. If it doesn't, you will need a new diaphram. It sounds like the latter.
