Paolo928

Hi there,
I have a 1983 Porsche 928s 5sp that needed new brake pads so I took it to a "reputable" mechanic here in San Francisco to get the job done. I provided the pads. When I was told that the job was done I went to pick up the car, paid and drove away. Well, luckily nobody crossed the road in front of me, because when I pressed the brake pedal there was no brakes at all for a while. Then one side started working more than the other, the right side, pulling to the right really bad. I also noticed that the car didn't drive freely, that the brakes were still partially compressed even when I was not braking. I went back to the shop and I explained the situation to the man. He told me that he didn't have anything to do with it, that all he did was to press the calipers to get the pads out and install the new ones. Then he said that the calipers are 30 years old and with some driving the pressure will normalize, and that the hoses are bad and need to be changed. I managed to drive around town for a while now but nothing changed. Now I don't want to bring my car back there because I don't want this people to screw up something else. I did some work on my car my self in the past (injectors, vacuum lines, alternator, starter and other random stuff) and I prefer to screw it up my self. I should just have read Dwayne's guide and done it my self. Is there someone that had a similar problem?

Arominus

Time to bleed your brakes as a start, it's easy. As for your hoses, if they are over 10 years old or show any cracking in the rubber I would replace them.

Charley B

Did you tell the shop to replace the pads or did you tell them to do a brake job. Big Difference. If you instructed them to replace the pads then any other problems are still yours. It sounds like the pads are dragging and probably need the calipers rebuilt.

If you're up to the task, Dwaynes write up is an excellant resource and should be all you need. Read through the whole procedure first and make sure you have the tools and nuts to tackle the job.

Paolo928

Thank you Arominus and Charley B for responding so promptly.
Yes Charley B, I brought in brake pads and only asked to put them on for me. No issues before that. I was just trying to provide as much info as possible...
Here are other detail about this interesting phenomenon:
- At low speed (v<45)is hard to tell.
- At high speed it pulls right when breaking and then left when releasing the pedal.
- The drag effect only lasts about 30 seconds after releasing the pedal.
I'll start with bleeding the system and if doesn't work I'll try the rebuilt. Is the bleeding procedure also on Dwayne's write up?

James Bailey

They we not happy installing customer supplied parts so the did exactly as you asked...put on pads. They never bothered to test drive it which is a pretty bad business practice.
The pistons were way back and the first time you hit the pedal it took a pump or two to push them out which is normal but they usually do it before or during their test drive. The uneven braking/draging is probably a piston/seal hanging up on corrosion in the cylinder. The piston is now sitting much further into the cylinders than they have for years due to the full thickness of the new pads. Those areas of the cylinders get attacked by the mosture which gets absorbed by brake fluid (why it needs to be changed every two years). So now the calipers need rebuilding with new seals, and a good time to fit new brake lines.

Charley B

When pads are replaced after years of slow use the pistons must now travel back to an area in the caliper that has hardened and become gunky from non use. Sometimes this can be eliminated by hundreds of brake applications but generally the calipers must be dis-assembled and the cylinders cleaned out.

It is not the fault of the brake shop. They just complied with your ill advised request.

The reason it seems to pull left when you release the brakes is because you are already counter steering left in order to hold against the pull to the right.

The symtoms you describe will probably not be ameliorated by bleeding the brakes.

Charley B

Sorry Jim. Looks like we were "talking" at the same time.

James Bailey

No problem at least we agree

Mrmerlin

I would also speculate that your going to need a new MC,
since with the new pads the MC has seen full stroke in the bore,
it is common for the bore to corrode on the non used section of the bore,
and take out the seals if its pushed past the normal working area of the bore.


So do it right the first time ,
new MC,
new SS lines,
rebuilt calipers
fresh ATE super blue racing fluid

Paolo928

Hello everybody, thanks for your help. Nice to meet you Arominus, Charley, James and Mrmerlin.
I found some remanufactured front calipers (AUTOSPECIALTY / KELSEY-HAYES ) and hoses for pretty cheap. Should I just get those or insist on rebuilding mine? I think that would save some time I can redirect to other issues (discussed in another post

Paolo928

Are newer model calipers (like s2 or s4) a direct fit replacement or would need also the master cylinder to be replaced?

Lizard928

The rebuild kits are cheap for your "S" brakes.

Just pull and rebuild your own!

Paolo928

Thanks for the advice Lizard931... will take care of that over winter brake...

Paolo928

Hello there, back in business!
Today I replaced hoses, calipers and filled up with fresh fluid. I only bleed the front then is got dark out. Tomorrow I'll bleed the rear calipers. I did go on a test drive: my problem is gone :-)
Pedal has a much smoother action and maybe feels a little softer than before... I'm very happy with the result. Thank you all for your support and recommendations.

James Bailey

Good news . Glad it worked out for you !!