Need help with brakes
Thread Starter
Pro
Joined: Oct 2005
Posts: 505
Likes: 8
From: Houston Tx.
Need help with brakes
I have been battling a soft pedal for some time now. I replaced the M/C, booster and calipers back in 2003, but the car has only seen a few thousand miles since then. A couple of weeks ago I found the right rear caliper leaking, so I bought a set of Wilwood calipers, hoping to be done with it. After installing and bleeding the Wilwoods, the pedal was rock solid, until I started the car. The pedal went to the floor. Pumping the pedal builds pressure, but when holding it, it slowly goes back to the floor. No leaks are evident under the car. Am I looking at a master cylinder or booster problem or both?
Pro
Joined: Oct 2009
Posts: 523
Likes: 4
From: Calgary Alberta
I have been battling a soft pedal for some time now. I replaced the M/C, booster and calipers back in 2003, but the car has only seen a few thousand miles since then. A couple of weeks ago I found the right rear caliper leaking, so I bought a set of Wilwood calipers, hoping to be done with it. After installing and bleeding the Wilwoods, the pedal was rock solid, until I started the car. The pedal went to the floor. Pumping the pedal builds pressure, but when holding it, it slowly goes back to the floor. No leaks are evident under the car. Am I looking at a master cylinder or booster problem or both?
The C3 is a pain in the butt to bleed the brakes. I tried a two man manual bleed and the gravity bleed processes with no luck. Finally got a pressurized brake bleeder and now the Wilwoods with the Wilwood master cylinder works perfectly. The only other problem you might be having is that the front calipers are leaking like the rears.
But either way, you will need to bleed the system properly for it to work regardless of what calipers are used.
Hope that helps.
Thread Starter
Pro
Joined: Oct 2005
Posts: 505
Likes: 8
From: Houston Tx.
I will advise that you should get a brake bleeder system similar to the Motive bleeder and bleed the system again. Make sure you bench bleed the master cylinder to remove all the air before you bleed the calipers. Seeing that the M/C and booster is basically new it's not likely they have failed.
The C3 is a pain in the butt to bleed the brakes. I tried a two man manual bleed and the gravity bleed processes with no luck. Finally got a pressurized brake bleeder and now the Wilwoods with the Wilwood master cylinder works perfectly. The only other problem you might be having is that the front calipers are leaking like the rears.
But either way, you will need to bleed the system properly for it to work regardless of what calipers are used.
Hope that helps.
The C3 is a pain in the butt to bleed the brakes. I tried a two man manual bleed and the gravity bleed processes with no luck. Finally got a pressurized brake bleeder and now the Wilwoods with the Wilwood master cylinder works perfectly. The only other problem you might be having is that the front calipers are leaking like the rears.
But either way, you will need to bleed the system properly for it to work regardless of what calipers are used.
Hope that helps.
Thread Starter
Pro
Joined: Oct 2005
Posts: 505
Likes: 8
From: Houston Tx.
Success. And I think I have figured out the problem. I went back and read the GM manual on brakes, specifically pressure bleeding, and I found the statement that a diaphragm type pressure bleeder with a rubber diaphragm between the air pressure and fluid must be used. Looking a t my pressure bleeder, the hand pump extends down into the bottle into the fluid. So, as I pumped up the bottle, I was probably aerating the fluid and pumping the entrained air bubbles into the system. I am going to redesign my bleeder so the fluid does not come in contact with the pressure source.
