| Author |
Message |
Joel Belser (Driver)
New member
Username: Driver
Post Number: 46
Registered: 9-2002
| | Posted on Friday, October 17, 2003 - 2:51 pm: | |
I had brake lines that looked OK, but were subject to internal collapse! The car pulled to one side under high speed braking. Bleeding the system did not help and visually, everything appeared fine. Changing the lines did the trick. |
MICHAEL MORETT (Thecarreaper)
New member
Username: Thecarreaper
Post Number: 17
Registered: 9-2003
| | Posted on Tuesday, October 14, 2003 - 8:54 pm: | |
sticking or defective brake proportioning valve, may allow a push-pull hydro failure. i want a 308, i dont have one ( yet ) so i am unfamiliar with the look and routing of the system. if it has a proportioning valve that is bad or has trash in it this may be the cause if the master cylinder checks good. just my .02. i have had this same exact problem with some other older cars good luck. |
Gianluca Chegai (Gianluca)
New member
Username: Gianluca
Post Number: 27
Registered: 5-2003
| | Posted on Tuesday, October 14, 2003 - 7:58 pm: | |
Mike,
I had to replace my right rear rotor and the other had a small "lip" from wear. I did not have it turned but I replaced both rear set of pads.
When I tested the car, it was definately pulling to the right big time! Once the left pads were able to adjust "around" the lip the car was braking fine.
So, it will pull to the side due to the rear brakes.
Sorry I can not help with the other problem but, given the symptoms, I would double check your rear right caliper and lines going to it. ( as it seems the right rear is doing its job and you have not touched the front calipers).
Best of luck,
Gianluca
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Mike Procopio (Pupz308)
Member
Username: Pupz308
Post Number: 564
Registered: 10-2002
| | Posted on Tuesday, October 14, 2003 - 2:33 pm: | |
Thanks for the continued input, guys.
I definitely have the rear calipers mounted correctly (ebrake adjustment on top).
Ken, did you rebuild or replace your master cylinder? If replaced, did you include the brake booster unit?
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Ken Sullender (Sulley)
Junior Member
Username: Sulley
Post Number: 120
Registered: 9-2003
| | Posted on Tuesday, October 14, 2003 - 9:03 am: | |
Remember too as you are replacing new pieces of a brake system it is common to find a new 'weak link'. When I put new calipers on it caused the master cylinder to fail. |
Phil Hughes (Ferrarifixer)
Junior Member
Username: Ferrarifixer
Post Number: 234
Registered: 7-2003
| | Posted on Tuesday, October 14, 2003 - 3:58 am: | |
Try putting a couple of the bleed screws directly in the m/cyl and then bleed it in it's isolated state. You may need to make short test pipes on some cars to ensure the bleeders are high and not inverted.
The pedal SHOULD be incredibly firm, much firmer than it would be even normally. Almost solid in fact. If it is not, then the m/cyl should be given a birthday. If it is, then the problem lies further down the system, and by systematically moving your bleed screws further down the lines (using adaptors where necesssary), you'll eventually find the problem and fix it at the expense of only time, fluid and the real faulty part, if any.
Dumb question here, but just check you've not got the rear calipers on the wrong sides. If you do, the hand brake levers will be on the bottom, as will the bleed screws. Both need to be on top. Series 1 246 Dino's had inverted rear calipers and it tripped me up as an 18 yr old apprentice....lesson learned, as was this test procedure. |
Don Norton (Litig8r)
Junior Member
Username: Litig8r
Post Number: 246
Registered: 6-2001
| | Posted on Tuesday, October 14, 2003 - 2:15 am: | |
Sounds like a bad master cylinder. I had a pedal to the floor symptom. It also could be cured by pumping. R&R master cylinder fixed it. |
Mike Procopio (Pupz308)
Member
Username: Pupz308
Post Number: 562
Registered: 10-2002
| | Posted on Monday, October 13, 2003 - 10:37 pm: | |
Peter,
I replaced the fronts earlier this year, and just did the rear calipers... So it's "probably" the rears causing the pull--but could be the fronts.
The brake pads did in fact fit OK--I retracted the pistons using the clearance adjustment mechanisms that are part of the caliper, then reset the pad-to-rotor distance to .004" as prescribed in ATE brake manual.
My biggest concern is how the brakes are behaving--they WILL bite, but with a few quick primer pumps on the master. I wonder if these "primer pumps" are building up pressure that hides the presence of air (by compressing it), or if it's more indicative of a problem with the master?
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Philip Airey (Pma1010)
Member
Username: Pma1010
Post Number: 479
Registered: 7-2002
| | Posted on Monday, October 13, 2003 - 10:08 pm: | |
Mike
Sounds very frustrating. I've never had a rear caliper cause the car to pull to one side (always the fronts), so you're sure it is a problem with the rears, right?
However, assuming it is the rears, if it pulls to the left, the LH rear caliper is biting, and the RH is not. Is one of the passenger side pistons getting hung up? Also, is there enough clearance between the pad/backing plate and the wall of the caliper? I've had to file brake pads down to get them to fit before where too much material had been added to the backing plate and it was fouling on the caliper. |
Mike Procopio (Pupz308)
Member
Username: Pupz308
Post Number: 561
Registered: 10-2002
| | Posted on Monday, October 13, 2003 - 9:44 pm: | |
Jim,
Thanks for the help. I did in fact bleed the master a number of times when I was doing the brake-pedal push style bleeding, and even when I did the mighty-vac suck type bleeding. I've definitely had air in there by the nuts at the master as you point out.
HOWEVER, I have NOT bled the master since I pressure bled the whole system--that would be the most thorough thing to do but if I've understood correctly, when you flush the system via a pressurized brake fluid source, doesn't that make it impossible for any air bubbles to remain at the master?
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Jim Avery (Boxer12)
Member
Username: Boxer12
Post Number: 389
Registered: 6-2003
| | Posted on Monday, October 13, 2003 - 9:36 pm: | |
Mike, have you bled the master cylinder? You have to loosen the brake lines at the master to do this.
Hang in there, be methodical,you will get it. Jim |
Mike Procopio (Pupz308)
Member
Username: Pupz308
Post Number: 559
Registered: 10-2002
| | Posted on Monday, October 13, 2003 - 9:26 pm: | |
After replacing the rear calipers and pads, I still don't have my 308 brakes right.
I'm ready to throw in the towel.
Last weekend, I borrowed a 1-gallon PRESSURE BLEEDER from a local brake shop and pressure bled the system with them. I watched as nothing but a nice, clear steady stream of brake fluid came out of each caliper.
Still, the pedal was soft.
It's very strange, how the pedal is. I CAN GET firm pressure, but I have to do a few quick shallow pumps before hand. Then I can get firm pressure--enough to lock up the brakes. The pedal DOES NOT fall or slowly sink.
After I've been off the brakes for about 15 seconds, I can SLOWLY push the pedal all the way down, almost to the floor. This is definitely not the way it was before.
These are rebuilt calipers from T. Rutlands, I have them on the front w/o issue.
I've adjusted the e-brake, and it holds fine. I've set all the clearances. New porterfield R4-S pads all around. (However, the problem was there even AFTER I put on the new calipers, but BEFORE I put on the new pads).
Two STRANGE symptoms I've had:
1. The car pulls to the left under hard braking.
2. If I put my ear up to the rear left caliper, and have somebody pump the brakes, I hear what I THINK are air bubbles being blown into the caliper (like the sound made by blowing air into a straw in a full drinking glass). This suggests air is getting into the system somewhere?
I did have to bend my hydraulic "hard line" (aka s line) a few times to get it to fit after reinstalling the caliper...
BUT, I have NO brake fluid leaks. Also, the bleeder screw is tight and I've wrapped all bleeder screws in teflon tape.
Is this a problem with the master? I've read one thread where a FerrariChatter had a problem with no pressure when the brakes were SLOWLY applied--related to problems with degradation in the seals in the master cylinder. Which might have happened, since I first tried the manual two-person brake pedal to the floor style brake bleeding, which I understand can ruin the seals in the brake master.
Any direction on where to go now?
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