Power Brake booster testing
Thread Starter
Drifting
Joined: Apr 2017
Posts: 1,336
Likes: 287
From: Minnesota
Power Brake booster testing
Hey guys, I've recently developed an issue where the brakes feel just a tad bit squishy however the car does stop.
1989 Z51, ZF6 (70k miles)
While bleeding I was able to do all 4 corners so I assume the MC and the ABS unit are fine, also the front and rear fluid reservoirs emptied accordingly to the bleeding. All 4 calipers clamp the rotors when pressed.
Any tips would be appreciated, haven't had to do anything brake booster related on a C4, just caliper rebuilds and an ABS unit rebuild...the booster is new territory for me.
Thanks
1989 Z51, ZF6 (70k miles)
- New brakes last year
- Sst line at the corners
- Rebuilt calipers (all 4)
- Cleaned the master cylinder
- No fluid leaks anywhere that I can see
- Hissing from the firewall when applying brakes (will investigate this more tonight)
- Re-bled the lines
- Used a hand pump to test vacuum however wasn't sure how much pressure to use (only used 15psi, it held pressure)
While bleeding I was able to do all 4 corners so I assume the MC and the ABS unit are fine, also the front and rear fluid reservoirs emptied accordingly to the bleeding. All 4 calipers clamp the rotors when pressed.
Any tips would be appreciated, haven't had to do anything brake booster related on a C4, just caliper rebuilds and an ABS unit rebuild...the booster is new territory for me.
Thanks
Last edited by mark970; Jun 24, 2024 at 08:08 PM.
Thread Starter
Drifting
Joined: Apr 2017
Posts: 1,336
Likes: 287
From: Minnesota
Thanks for the quick responses
I did manage to perform a test that gave me negative results...
I did manage to perform a test that gave me negative results...
- brakes were firm with nothing turned on
- coudn't hear the hissing after starting (too loud in the garage)
- sprayed soapy water around the outside of the check valve...big BUBBLES when pushing in the pedal
Last edited by mark970; Jun 25, 2024 at 02:37 PM.
Thread Starter
Drifting
Joined: Apr 2017
Posts: 1,336
Likes: 287
From: Minnesota
