'85 Calipers

[85911]

I'm about to rebuild the calipers on my '85 and am considering painting them. Does anyone know what the original color was?

And, what color(s) would you recommend?

Thanks.

[Rodney Nelson]

Check out PMB site as they explain all of the differences in calipers for the different years including finish.

https://www.pmbperformance.com/mid-911-brakes.html

[85911]

Thanks, Rodney.

[85911]

From the PMB Performance website, it looks like they were coated with something that looks like yellow zinc plating.

[Rodney Nelson]

Yes, that would be my guess. I emailed them a few months ago and they replied with a long detailed answer. So, I would just send them a quick email and ask for sure. If you have the funds I would just send them to PMB, as they will plate them and rebuild them to as new condition, the right way. If you are trying to save money you could find a local finisher and have them finished with gold zinc. However, you need to make sure they understand what areas need to be protected during the process. Then you can rebuild them yourself. I have a killer set of 72+ S Calipers that I found here on the classifieds board. When I'm ready I'm definitely going to send them to get refinished and rebuilt by PMB.

[GH85Carrera]

Originally Posted by 85911

From the PMB Performance website, it looks like they were coated with something that looks like yellow zinc plating.

This.

I have a 85. When I purchased it the passenger side front caliper had a big stain of rust like tint. I ignored it for several years. I rebuilt my calipers when I re-did the rubber bushing in the suspension, and the shocks and the other parts.

Finally I just got tired of the stain, and I sent them to PBM and had them rebuilt, and the cab plating look back to stock. They look and work like new ones. They somehow seem to work a bit more evenly than when I rebuilt them.

It is not a fast process, and takes several weeks. If you are in a hurry you can likey do an exchange.

[85911]

I've decided to tackle the refurbishment myself. A local plating company said cadmium plating is rare now because of environmental issues with the process, and it is very expensive. They yellow zinc plate a lot of auto parts. He suggested the caliper halves be glass bead blasted prior to plating which he could perform.

The blasting and plating would be about $200 for 8 pieces.

I have the o-rings for the caliper half ports.

I would be interested in anyone's comments that has done this themselves.

Thank you.

[Walt Fricke]

Abrasive blasting requires extremely thorough cleaning afterward to insure none of the media used is inside any of the hydraulic area.

[Flojo]

Ate Calipers throughout the G series (A and M) are yellow zink-ed
The 930 Brembo are kind of DLC coated (for sure it's different than just anodized).

First time Porsche had painted calipers were the 964 C2 Aluminium ones

[Quicksilver]

It is so much better of an option to have Eric at PMB do the calipers. Imperfect caliper rebuild can give you a caliper with too much seal retraction that makes it so you end up with "fresh brakes" that require extra brake travel before they bite, or even require you pump them!

Eric does the most perfect rebuild and it is well worth the cost to have it done right. I bought some "professionally rebuilt" calipers that had all new hardware and they required a double pump each time to get the pedal hard. I expected that a little break in would get the seals broken in and get the seal retraction under control. After 2500 miles I gave up and had Eric send me one of his pairs.

Problem solved.

[gtc]

+1 to the above.
I rebuilt a spare set a few years ago. The small amount of money I saved was not worth the time and effort, compared to what PMB charged. In particular, the rear dust seal on these is a real PITA to install.
Mine work great, but I wouldn't bother with it again.

[Jack Stands]

Save yourself grief, send them to PMB. Proper finish and minimal downtime.

[85911]

I appreciate the responses. Regarding the suggestion to save myself time and trouble, cars and motorcycles have been my hobby for 54 years. I thoroughly enjoy this type of work. So, there's nothing to avoid, but an opportunity to have some fun.

I do understand the reservations. I have successfully rebuilt calipers on other cars including one on this '85. I had no issues with the rebuild including the dust seal (although I don't understand the reference to a "rear dust seal" above). I understand the cleaning issue.

I purchased the kits and o-rings from PP for around $240. That's a big difference from $1,300.

I need to assess the reservations expressed above, although I don't see a technical obstacle that would prevent me from successfully doing the work.

Thanks to all for your replies.

[Walt Fricke]

85 - I'm with you.

I've not had an issue rebuilding calipers. I had an issue when first I went to stainless pistons. The ones I purchased for the rear were too big! I could force them in, but they were basically stuck, so wouldn't retract. The seller corrected that for me.

Recently I used PMB because I thought I might have a slight retraction problem with just one piston. I've buffed my stainless pistons, but they have ways of doing better, and of course a better feel for what inserting the piston should feel like - plus they spiffed up the appearance of my 1977 calipers. I just wasn't interested in doing that myself, though I could have, using something other than actual plating.

Otherwise I'd just do mine - not difficult at all if you have the basic mechanical mindset - like you know, just from thinking about it, you need to put a wood block or something in there when hitting it with air to get the pistons out.

The rear dust seal issue has to do with getting the thing on. Seals come in two flavors when it comes to retention. One is a two piece deal - rubber seal, and a split steel ring. Put the seal on over its lip on the caliper, push the split ring over it and down into the channel, and you are good. It may be that this style is found only for the front A/S caliper?

The other has something like the steel split ring molded into the seal. Those are a real PITA, at least for me and many others. Hard to press evenly all the way around its circumference to get it to go on over its lip.

I deal with this by omitting the seals, but that's for a track only car, where the seals pretty promptly get brittle from heat and bits break off. And no driving through salty or mag chloride water. I've gotten them on in the past, but only with a lot of bad language and way too much time. Some doubtless have developed the knack - maybe you will also. But not a big deal one way or the other. It is not like trying to do a valve job with a few ordinary hand tools.

[Jonny042]

PMB does really nice work and I would recommend them to 90% of people.

However, the other 10% of the world has more time than money, or other valid reasons for wanting to DIY. Rebuilding a caliper is not rocket science..... If you like to tinker, by all means do them yourself, especially if you have found a plater to take a small job. Careful, though..... you are standing at the top of a very steep, nearly frictionless, slope.... it might be a really convenient time to unbolt a few other dull bits to get them plated. Might I suggest brake backing plates?

[85911]

Walt and Jonny: Thank you for your replies. You have sufficiently reinforced my perception that this is a task that a DIY'er can do. Yes, I have the time and will enjoy the process. As I stated in an earlier post, this plater has experience with yellow zinc plating auto parts, so I am comfortable with him doing the job. And, I haven't found installing the caliper kit (the flat o-ring, piston seal, and retaining ring) particularly difficult. It was pretty easy.

I was going to ask about the original finish of the brake backing plate and you already answered. I assume they were originally yellow zinc plated, correct? If so, I will throw them in with the batch. The plater indicated his minimum charge is $125. for the plating and that I could throw in about a bucket's worth of pieces with the calipers to meet the minimum charge.

My split rings are separate from the rubber seal and the new ones were quite easy to install.

I will be using the original pistons. I have tracked the car, but will not do so again- I'm getting too old to put such a fine car at risk. So far on the caliper I rebuilt, the pistons came out easily with compressed air. The 2 pistons had several spots on them, but they readily came off with a little work with a green Scotch Brite pad.

Again, thank you for your input.

[Walt Fricke]

I recall the brake backing plates on my '77 were just painted black. They are a dust shield, intended to reduce the amount of brake dust which gets spread around. They are the first thing a guy who tracks his car discards. I did, and the car was my daily to work driver for 20 years, and I never missed those plates.

But my memory may be failing me. Mine may have been grunge covered plating. I donated the plates to PMB when he was just starting his business. Contact them - they will know if no on else knows.

[85911]

Walt: Thank you very much. I would like to keep this car original, so I will contact PMB. Mine are a grunge black, so it's hard to tell what the original finish was. And, while I'm in there, I might as well refurbish them too.

[85911]

Does anybody know what the original finish was on '85 911 brake backing plates?

I called PMB and the technician wasn't available.

Thanks.