Brake master cylinder question
Thread Starter
Melting Slicks
Joined: May 2003
Posts: 2,851
Likes: 1
From: San Bruno Ca
Brake master cylinder question
I've done brake jobs on many cars before including my old C-3, where the master cylinder must be power blead to avoid nicking the rubber O-ring seal on the plunger. My question is can you bench bleed the C-5 master cylinder manually or do you have to power bleed it?
Thanks for any info, you guys are great!
Thanks for any info, you guys are great!
Safety Car
Joined: Jul 2004
Posts: 3,904
Likes: 29
From: Vancouver Washington
Yes, the C5 master cylinder can be bench bled manually. The factory service manual does mention using a smooth, round-ended tool to depress the primary piston about an inch to activate the bleeding process.
Le Mans Master
Joined: Sep 2003
Posts: 8,847
Likes: 795
From: Longview Texas
I replaced my master cylinder a few months ago and bench bled it.
It turned out that with the reservoir cap off, the fluid ran through the master cylinder, and essentially bled itself. I had to put the cap on to keep the brake fluid from continuing to run through the cylinder so I could put it back on the car. I did push the plunger in a few times, but all I really did was make a bigger mess.
After I got the cylinder back on the car, I cracked the brake line fittings and bled each port. This would have been sufficient for a solid brake pedal, but since I had never flushed the system, I went ahead and bled each caliper until I got clean fluid.
Brakes have worked flawlessly.
My service manual has the procedure for bench bleeding and it actually says to push the piston in "as far as it will travel, a depth of about 1 inch".
It turned out that with the reservoir cap off, the fluid ran through the master cylinder, and essentially bled itself. I had to put the cap on to keep the brake fluid from continuing to run through the cylinder so I could put it back on the car. I did push the plunger in a few times, but all I really did was make a bigger mess.
After I got the cylinder back on the car, I cracked the brake line fittings and bled each port. This would have been sufficient for a solid brake pedal, but since I had never flushed the system, I went ahead and bled each caliper until I got clean fluid.
Brakes have worked flawlessly.
My service manual has the procedure for bench bleeding and it actually says to push the piston in "as far as it will travel, a depth of about 1 inch".
Last edited by TEXHAWK0; Aug 5, 2009 at 11:14 AM.
Thread Starter
Melting Slicks
Joined: May 2003
Posts: 2,851
Likes: 1
From: San Bruno Ca
Thread Starter
Melting Slicks
Joined: May 2003
Posts: 2,851
Likes: 1
From: San Bruno Ca
I replaced my master cylinder a few months ago and bench bled it.
It turned out that with the reservoir cap off, the fluid ran through the master cylinder, and essentially bled itself. I had to put the cap on to keep the brake fluid from continuing to run through the cylinder so I could put it back on the car. I did push the plunger in a few times, but all I really did was make a bigger mess.
After I got the cylinder back on the car, I cracked the brake line fittings and bled each port. This would have been sufficient for a solid brake pedal, but since I had never flushed the system, I went ahead and bled each caliper until I got clean fluid.
Brakes have worked flawlessly.
My service manual has the procedure for bench bleeding and it actually says to push the piston in "as far as it will travel, a depth of about 1 inch".
It turned out that with the reservoir cap off, the fluid ran through the master cylinder, and essentially bled itself. I had to put the cap on to keep the brake fluid from continuing to run through the cylinder so I could put it back on the car. I did push the plunger in a few times, but all I really did was make a bigger mess.
After I got the cylinder back on the car, I cracked the brake line fittings and bled each port. This would have been sufficient for a solid brake pedal, but since I had never flushed the system, I went ahead and bled each caliper until I got clean fluid.
Brakes have worked flawlessly.
My service manual has the procedure for bench bleeding and it actually says to push the piston in "as far as it will travel, a depth of about 1 inch".
I'll try to remember to leave the resevoir cap on when installing the MC on the car.
Thanks for your help also.
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