Spongy/soft brake pedal
Thread Starter
Cruising
Joined: Jul 2023
Posts: 10
Likes: 1
Spongy/soft brake pedal
Hi guy's,
hope someone can help me out here as I'm stuck with a bit of a mystery.
I decided to rebuild every brake component on my 78 Anniversary.
The brakes were working fine before, but looked very crusty.
So this is what I have done so far.
Rebuild front and rear calipers. (pistons were fine and not pitted)
New rubber brake hoses front and rear.
Brake pads front and rear.
Master cylinder, bench bled.
After rebuild I tried gravity, assistant aided, power and reverse bleeding.
Can not get a hard pedal.
More bleeding off all sorts, no luck.
Changed the booster, still the same problem.
Decided to try the old MC again, with all the bleeding techniques and at that point still no hard pedal.
I think I have tried everything you can known by the book.
The only thing that is not as the old system are the rebuild calipers.
Did I do something wrong here? Is there a special technique to bleed rebuild calipers.
Greetings from Belgium!
hope someone can help me out here as I'm stuck with a bit of a mystery.
I decided to rebuild every brake component on my 78 Anniversary.
The brakes were working fine before, but looked very crusty.
So this is what I have done so far.
Rebuild front and rear calipers. (pistons were fine and not pitted)
New rubber brake hoses front and rear.
Brake pads front and rear.
Master cylinder, bench bled.
After rebuild I tried gravity, assistant aided, power and reverse bleeding.
Can not get a hard pedal.
More bleeding off all sorts, no luck.
Changed the booster, still the same problem.
Decided to try the old MC again, with all the bleeding techniques and at that point still no hard pedal.
I think I have tried everything you can known by the book.
The only thing that is not as the old system are the rebuild calipers.
Did I do something wrong here? Is there a special technique to bleed rebuild calipers.
Greetings from Belgium!
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
Have you tried gravity bleeding the calipers removing about a cup from each caliper? (Be sure to keep an eye on the m/c to ensure it's kept properly filled).Time consuming but this method has always worked for me.
Thread Starter
Cruising
Joined: Jul 2023
Posts: 10
Likes: 1
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
Thread Starter
Cruising
Joined: Jul 2023
Posts: 10
Likes: 1
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Let me throw some ideas at you.
You say assistant aided method. Don't like the sound of that.
Nothing wrong with someone on the brake pedal while you open / close bleeders. EXCEPT on a C3.
The pedal throw is so short on these cars that it's to the floor before the assistant can close the bleeder. Air enters.
And, more than likely you just "tripped" the proportional valve. It can't tell if the leak is a test or just bleeding. So, it shuts off the rear system, or front.
You also mentioned, bench bled the M.C. And that's fine as long as you did not force the piston in too far. That accidental task will void warranty on new or rebuilt units.
Click on my avatar and look for bleeding photo album about this subject of internal damage to the M.C.
You say assistant aided method. Don't like the sound of that.
Nothing wrong with someone on the brake pedal while you open / close bleeders. EXCEPT on a C3.
The pedal throw is so short on these cars that it's to the floor before the assistant can close the bleeder. Air enters.
And, more than likely you just "tripped" the proportional valve. It can't tell if the leak is a test or just bleeding. So, it shuts off the rear system, or front.
You also mentioned, bench bled the M.C. And that's fine as long as you did not force the piston in too far. That accidental task will void warranty on new or rebuilt units.
Click on my avatar and look for bleeding photo album about this subject of internal damage to the M.C.
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