Redoing Brakes

I posted this question in the alloy pads topic, but I think it got lost in the fray.

What are the steps involved with doing your own brakes? I know you have to pull the pin out, and then the pads, to replace them. But what else does one do when "doing" the brakes on a 911?

Forgive the pretty basic question.



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Mark Szabo
1986 911 Targa 3.2

Mark:

This is really an easy project, so don't hesitate. I have a 1983 911SC, so things may be a little different in your wheel-well, but the principle is the same.

One you have removed the wheel, do the following:

1. Remove the pins. This is easy if you have a long-necked punch, of the right diameter to fit the pin hole; can get them from Sears.
2. Using either a screwdriver or other type lever, fulcrum (verb transitive) the old pad back into the caliper (careful not to fulcrum off anything delicate, as you will bend it), and don't scratch the disc itself. I use the screwdriver blade in the pin-slot of the old pad.
3. Carefule not to let the brake fluid overflow the reservoir; you will be effectively forcing the pad back and the fluid back with it to the reservoir.
4. Remove the old pads; you have to be sure to get them loose enough to pull them out. The dealer techs may or may not use an official "puller", but you should be abel to lever them out.
5. Now is the delicate part, so be careful not to scratch your rotors. You have to push the caliper pucks back far enough to get your new pads into the slot. I use the same large screwdriver, with a rag on the tip, to lever the pucks back in.
6. Coat the back of the new pads with hi-temp grease, place any anti-squeal shims back, or the wear-sensors if you have them, and slide the pads into the slots from where you removed the old pads. Keep levering in the puck if they don't just slip in. Careful also not to damage the rubber boot around the pucks; these actually retract your pucks, and thus your pads, when you release the brake. This is the simple self-adjusting device Porsche uses.
7. Replace the pins, and drive them home with light taps from a small hammer. Do not over-drive; just enough to seat them or enough to expose the holes for the little "cotter pins".
8. NOW VERY IMPORTANT; get in the car and pump the brakes to seat the pads against the rotors. If you don't, you will be unpleasantly surprised when you take your first drive and don't have brakes; better to pump in the garage than on the road at speed.

Tha's all there is, folks. Nothing too comlicated.

By the way, do you speak Hungarian? Your name is Hungarian for "tailor".....Andras

Thanks Andras! No, I don't speak but one word of Hungarian - "tailor"

I'll look for some more info on this and probably get started in a week or two. Pictures would be helpful but those are hard to post in UBB (but possible). Thanks again for the info!



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Mark Szabo
1986 911 Targa 3.2

What is the procedure for rebuilding the calipers?

It would be a good idea to get your rotors turned when you replace the pads, just to insure a 'smooth' pedal, and more efficient braking from the new pads and a smooth, flat surface on the rotors. Typically, 911 rotors do not wear very quickly, so there is usually plenty of 'meat' for a cleanup turning.


A rebuild of the calipers is also a fairly easy home job, if you are careful, patient, and take your time. Haynes manuals have fairly good instructions, but the instruction sheets packaged with OEM ATE (Teves) rebuild kits are good, too. A Vise-Grip 'C' clamp and a block of wood is helpful to get caliper pistons out with a variable-pressure air supply (15-40 psi) and a blowgun nozzle with rubber tip.


Rebuilding all of the calipers and master cylinder yourself every 3-5 years is not too expensive, parts-wise, and gives you a chance to completely blow-out the lines and get rid of 100% of the old brake fluid that tends to 'pool' in the calipers and doesn't get changed with a simple 'flush' job. It's a good time to replace the flexible rubber hoses with OEM replacements at each caliper rebuild, too. In my opinion, it takes two people the bleed the brakes properly!

Thanks for the caliper information.

just want to support earlier information. I just got done re-building the calipers. did all 4 in about 3 hrs (once I had the whls off). twas straight forward and simple.
One suggestion.... get PLENTY of brake cleaner and fluid. AND AND AND.... get a vaccum line plug kit from any parts store, use the smallest to cap the metal brake line when you remove your caliper and you wont lose all the fluid on the garage floor..

Did you guys rebuild the early alloy ("S") calipers, and if so did you replace the pistons? I've been hesitant to dive into my front calipers cause they are fairly rare and too expensive to screw up. Any special tips for these calipers?

I have rebuilt my 'S' alloy calipers a couple of times, and there is really only one 'caveat' ... use an OEM ATE rebuild kit!!! The first time I got ready to do it, I bought generic parts (Repco) at a BAP-Geon, and the dust boots were wrong, presumably for an 'A' caliper, or some other caliper with a 48 mm piston, but definitely not an 'S' caliper. I didn't need to replace my pistons, because there was no rust or pitting, just discoloration, and that cleaned up nicely with an ink eraser. I have used silicone brake fluid since mid-'78, so corrosion really hasn't been a problem for me! One thing I found out more or less by accident ... Raybestos rebuild kits for foreign cars contain OEM parts from that country, so their Porsche repair kits contain genuine ATE repair kits, in ATE boxes! One final note, if you are rebuilding calipers, you SHOULD disassemble the master cylinder and rebuild it at the same time, flush out the brake lines with 90% isopropyl alcohol, then blow dry with compressed air (equipped with air dryer and water trap) for 30 min. to an hour to be sure all the old fluid, water, and alcohol are GONE!!! You will have to use your own judgement as to whether OEM rubber hoses need to be replaced, surface cracks are a good indicator that time is near ...

If you get the idea I like to remove ALL traces of old brake fluid at each rebuild, that is right! The choice of replacement brake fluid is a hard one! I prefer silicone, but some people don't like a VERY slight 'sponginess' associated with silicones' affinity for air, but I always use a small, tilted funnel to put the fluid in the reservoir, very slowly, to minimize air bubbles, and I have no problem with sponginess on the highway, or in autocrosses!


One final suggestion, get some 'clear' silicone grease, 'Sil-Glyde', TRW Silicone Grease, etc. for coating pistons and seals, even if you are using conventional brake fluid! ATE has a very tiny tube of it in the rebuild kits for master cylinders, but not the calipers. It appears to be the same clear silicone grease in my TRW tube, and ATE calls it 'brake paste' on the tube, and on the instruction sheet.
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Warren Hall
1973 911S Targa

[This message has been edited by Early_S_Man (edited 01-28-2000).]

Warren,
You keep mentioning to replace the worn and cracked rubber brake lines with new OEM replacements. Are these rubber too? What do you think about those braided steel ones?

Jeff

Well, yes the rubber hoses do have a finite lifetime, although I can't tell you precisely what it is. The only OEM rubber brake hose I have ever experienced 'failing' happened while parking a '68 Plymouth 340S Barracuda in 1984! So it was no big deal, just a slightly bigger bump than normal against a curb. But, consider the possibilities, say stopping for a train crossing!!! My sincere recommendation would be to change the rubber OEM hoses with an identical hose every 10 years, or so. All rubber brake hoses I am aware of have a braided steel reinforced layer under the rubber, so essentially, the stainless hoses everyone is fascinated with are just like OEM hoses, but do not have an outer covering!

I have tried the stainless hoses, in the '70s, and experienced two failures, cracking near the fittings, at 8 and 10 years! So, I do not recommend the stainless, since the failures occurred SOONER than any OEM hose failure I am aware of. The same company that made the hoses that failed on me now make the hoses that meet DOT specs, Earl's Supply! I'm not saying they make bad hoses, but in 1978, when I first tried the stainless hoses, the assumption was that they would be changed every couple of years, at the maximum, since they were not approved for street use at that time, and each hose was labeled 'For Racing use only!' Use your own judgement!

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Warren Hall
1973 911S Targa

[DonDavis]

I was poking around at Warren's threads and posts and thought I would bump a couple.

A short while ago, LeeH and I replaced my brake lines with factory rubber ones. Someone asked me why I did not get stainless steel ones. I KNEW I had read something about it and it turns out it was Warren's post.

I probably read this thread when it was new. Warren's insight and logic always impressed me. Would liked to have met him in person and not just in cyberspace.