Brake troubles

[flatsixjunky]

Hello everyone,

Straight to the point, a couple of day's ago I felt the brake pedal started needing to be pushed more than once in order to get good pressure. Well, today all of a sudden my driver side front brake started squealing like a hog. I took the wheel off and this is what I saw.





I imagine I have to replace those 21 year old ugly rotors, mount new brake pads, new fluid and while in there new steel brake lines.

Do I need to do anything else? Am I missing something?

Thanks for the help.

[Flieger]

You might need to rebuild the calipers. If the bores get corroded or gummed up with old fluid they can stick and drag, causing friction and heat which boils the brake fluid causing a soft pedal and also causes the pad to overheat and smear material all over the rotors like you see there. Another cause of sticking is the rubber hoses swelling shut from the inside.

[flatsixjunky]

If the bores get corroded or gummed up with old fluid they can stick and drag, causing friction and heat which boils the brake fluid causing a soft pedal and also causes the pad to overheat and smear material all over the rotors like you see there.

from Flieger

Actually the squealing sounded like metal parts grinding each other, the current brake fluid and pads are actually like one year old (guesstimation) and has less than 6k miles on them. How would I know if I do need to rebuild the calipers?

Thanks,

Orlando

[Flieger]

It is good to bleed the brakes every year.

If the brake pads are worn unevenly (i.e. the inner is still thick but the outer is thin) it is a sign of a stick piston. If they do not retract fully and cause excessive drag on the rotor, they should be refurbished. You should be able to spin the rotor by hand when the car is on a jack stand with the wheel off. If you spin the hub, it should stop in about a quarter turn. If it takes so much effort that you cannot spin the rotor by the wheel stud and if the rotor stops immediately, then the brakes are dragging.

[Joe Bob]

If the caliper rebuild is beyond your mech ability or just want a real good job, contact Eric at www.pmbperformance.com I'm sure he still does them on an exchange basis.

[Mikey37027]

I just replaced my front rotors. If you have the front hubs off be prepared to repack/replace the front bearings.

[flatsixjunky]

Joe Bob, thanks but I'm in Europe.

Mikey37027, I just went through a search on "removing rotors" and just read the same advice on almost all the threads. I have a pair of bearings that I bought about a year ago and never used because I had misdiagnosed the problem, I'll use then now.

About rebuilding the calipers the question still stands, how would I know if I have to rebuild them?

Thanks,

-Orlando-

[Joe Bob]

If you have compressed air, you can pop the pistons out. It will be obvious.....if you have access to a Bentley manual or the downloadable "PET" it has all the tricks and pics of the procedure.

[flatsixjunky]

Originally Posted by Flieger

It is good to bleed the brakes every year.

If the brake pads are worn unevenly (i.e. the inner is still thick but the outer is thin) it is a sign of a stick piston. If they do not retract fully and cause excessive drag on the rotor, they should be refurbished. You should be able to spin the rotor by hand when the car is on a jack stand with the wheel off. If you spin the hub, it should stop in about a quarter turn. If it takes so much effort that you cannot spin the rotor by the wheel stud and if the rotor stops immediately, then the brakes are dragging.

Earlier today I had to apply a fair amount of pressure to be able to spin the wheel, it made a horrible metallic noise and it would not move at all after letting go. I guess calipers are toast too, *&#$ %#. Now I have to figure out the when and where am I going to do this.

Thank you.

Orlando

[Joe Bob]

You may be metal on metal. Do you see any brake material left?

[flatsixjunky]

Do you see any brake material left?

from Joe Bob

You mean pieces of brake pad? What material are you talking about?

Anyway it's been raining here non-stop for the last week and it doesn't seem like that's going to change anytime soon. I quickly took the wheel off today and took those pictures, I'm going to take a better look tomorrow.

BTW, I do have the Bentley.

Thanks.

[screenwriter-X]

Caliper rebuild is a very pleasant job and not that hard. Excellent how to here on Pelican: Pelican Technical Article: 911 Caliper Rebuild

Only other hint would be that you should get yourself a Gerber baby food jar lid for pressing those new rear caliper dustboots in properly until they pop into place.

I did my rears last Christmas time on my 1989 3.2. I also did all the things you're going to do. I ordered almost everything from free shipping warehouse internet places except for brake lines from Pelican. Cost me just a little over $1000 or so which included brand new front calipers and new front discs and new rear caliper springs and pins. In Canada. A weekend of work. Estimate at a local "specialist" criminal shop: $3500.

I can play my brakes like a fine musical instrument now. Completely stock Carrera 3.2 brakes properly renewed and rebuilt are ever bit as spectacular as all those magazine writers in 80's used to rave about. Porsche really, really knew what they were doing.

[flatsixjunky]

screenwriter-X,

I can only imagine, I've never done it. My problem is that I signed up to do my first ever track day, next Sunday and now this. I don't think I have the time to do this myself during the week. Even if I know a mechanic who's willing to show me how to do it, and let me use his equipment.

I think I'm going to have to cancel the track day. I've been waiting for months.

Thanks for the article.

O-

[Flieger]

My S calipers had been neglected for a long time and were not giving adequate pressure. I bought some beautifully rebuilt calipers from Eric Shea at PMB Performance and swapped them. I then sold my cores back to Eric for a fair price to recoup some of the investment. Only took an afternoon and the braking performance was much improved.

PMB Performance: We Don't Rebuild Your Brakes... We Restore Them

[356graham]

You've got a little over a week before the track day. If you go with exchanging your cores for rebuilt, you should have plenty time to get it done. Removing and replacing calipers is much faster than cleaning and rebuilding the calipers. Sorry, I don't know of a shop in Europe that provides that core exchange for rebuilt service.

Check your rotors to see if they are within spec. You need to measure the thickness of the rotor and check for uneven wear. It is possible that they are ugly, but don't need to be replaced. If you can't check or question whether needed - replace. Still not a hard job.

Check your rubber lines also.

You can get this job done in a week provided you have access to the necessary parts.

Don't rush, however. These *are* after all the most important safety item on your car.

[flatsixjunky]

Flieger,

That seems to be a great choice for restoring them to their original look, unfortunately I'm in stinky rainy Europe. I figure I have two options:

- Bite the bullet and leave the car at a shop on Monday = Track day on Sunday.

- Do it myself = Cancel track day on Sunday.

I have yet to order the parts anyway. I'm a confused man right now.

[flatsixjunky]

356graham,

I should give it a try, worst case scenario I'd be forced to cancel the track day.

I'm ordering the parts, this is my list so far:

- Stainless Steel Brake Hose Kit
- 2 Rotors
- 2 Caliper rebuild kit's
- brake fluid

Anything I'm forgetting?

Should I expect damage to the piston?
Tips for plugging the brake lines?

Thanks everyone.

O-

[zippy_gg]

Originally Posted by flatsixjunky

356graham,

I should give it a try, worst case scenario I'd be forced to cancel the track day.

I'm ordering the parts, this is my list so far:

- Stainless Steel Brake Hose Kit
- 2 Rotors
- 2 Caliper rebuild kit's
- brake fluid

Anything I'm forgetting?

Should I expect damage to the piston?
Thanks everyone.

O-

How are the rear pads and rotors? If you are going to flush the system you might as well rebuild the rear calipers and replace the rear flex hoses.

[flatsixjunky]

Originally Posted by zippy_gg

How are the rear pads and rotors? If you are going to flush the system you might as well rebuild the rear calipers and replace the rear flex hoses.

So here we go on the slippery slope of "while in there". I have to admit is good advice. I'll throw the rear kit in there too.

- Stainless Steel Brake Hose Kit
- 2F & 2R Rotors
- 2F & 2R Caliper rebuild kit's
- Brake fluid

Anything I'm forgetting?

Should I expect damage to the piston?

[G450X]

Not a bad job, just print out the forum tech guide and go step by step.

I'd do one caliper at a time just in case one of the pistons is stuck and you have to use hydraulic pressure to free it (I had to re-mount a caliper to free a piston, no helper).

You might price a rebuilt caliper to save time, they may not be too expensive.

FYI, my sticking caliper sounded just like a bad wheel bearing. It's a dirty job, but rewarding. I always thought a caliper was somehow complicated inside, but it's about as simple a piece as can be. The seals popped right in, just be careful keep the piston straight in the bore. I also made a template from the caliper piston before I removed it from the bore (1k miles and no squeal).