pgrunwald

I'm redoing my brakes and I'm thinking that while I have everything off, I should rebuild the calipers.

I have read the pelican page here: http://www.pelicanparts.com/techarti...er_rebuild.htm.

I have the Bently book and the 101 Projects book as well.

That said, I have not had a caliper off the car or actually looked at the part so if the answer if obvious once I see the part in real life, feel free to flame me...

I do not understand what is being measured for the 20 degree angle as shown in this picture. Is is a rotational angle (like a clock) of the piston to the sleave or a axis alignment of the piston in the sleave? Again, sorry to bother if the answer will be obvious once I see the inside of a caliper!

Second question is that I see caliper rebuild kits but I also read that I could split the caliper halves and I would need an inner O-ring. I don't see the inner O-ring listed at Pelican or Zims. I'm willing to split them, bead blast and the whole works. Should I plan to do that and where can I find the inner seals?

Thanks,
Paul

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'87 Targa

Brett San Diego

It'll be clear when you see the piston. The piston is like a pipe, hollow in the middle. The edge (face) of the piston that contacts the brake pad is not level all the way around. There is a section (about 120 degrees or so of the circumference) that is cut down about 1mm from the rest. One uses the 20 degree tool to set the edges of this cut section at a particular orientation against the tool, when the tool is placed in the caliper. Yes, it sets a particular rotational angle of the piston in the sleeve. I can't comment on the necessity of accuracy in setting this orientation.

I can't say anything about splitting the calipers, but I don't think it would be necessary to do a good rebuild (unless you have visible leakage).

If that's your car in your avatar, please tell me about the exterior blue.

Brett

Chris M.

I wouldn't split the halves unless you have leakage because as it says in the 101 Projects book, you may have leakage after putting them back together.
As far as the 20 degree angle goes, each piston has two notches. When you reinstall them, these nothces need to be at a 20 degree angle from horizontal just like the picture in the book and pelican article. You'll better understand when you get the piston in hand. I just cut a little triangular piece of cardboard with a 20 degree angle to line everything up.
The part # for rebuilding the calipers is 911 351 546 00. You'll need 2 of this part number as each one is for one caliper. Each box includes a piston seal, dust boot, and dust boot retaining ring. I got them for about $14 each from a local specialist.
Also, you will need an air compressor to get the pistons out. If you don't have one or access to one then you'll have to use the brake pedal to do it. They WILL NOT just pop out if you try and get them out by hand.
Good luck.

c

Bill Gregory

Don't split the calipers unless you have a known need to. The rebuild kits contain what you need to renew your caliper.

pgrunwald

Thanks again everyone for the great advise! I will NOT split them.

The color is called "Crystal Blau", it is factory paint job ordered under the Porsche "Special Wishes" program by the original owner. As far as I can tell, the last time the color was used in production was on the '67T'.

This is what my car wants to be when it grows up! http://www.mlodeent.com/IROC/dhir73.jpg

Thanks for asking!

Paul
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'87 Targa

77TARGA

DO NOT SPLT THE CALIPERS!!! I rebuit my rear calipers in my 77 targa according to 101 projects, of course it started as just a pad replacement, but then as I discovered they needed a rebuild I took them apart without having the parts yet (the rebuild kit was on the way) First thing I discovered it is fairly difficult to fing the right size torrex- T35 I beleive, but once I did, I took them apart and waited patiently for the kit from mid-america, Oh the joy when it came in, I ran down to my work bench where all the parts were already cleaned up and ready to simply be put back together, then I discovered the kit didn't include the o-rings... **** this means another week waiting for the parts, OK.... fast forward 1 week.... o-rings come in YEAH!!! run back to the work bench and begin reassembly, everything is going well, all back together, ready to torque the torrex bolts to specs, which is a 2 stage process... I'm getting psyched, almost done, Torque through the first sequence to specs, so far so good, start the 2nd go-round first bolt snaps ****! hunt around for the bolts ( no-body carries them) finally found them, wait yet another week for them to get to me, and finally get my brakes back together, all in all it took almost a month to do a simple caliper rebuild. DO NOT SPLIT THE CALIPERS!!!!!!!!!!!!!!!!!!!!!!

g-50cab

Don't split the calipers - no need. = many of the questions you have will be really evident once you dive in. When you pop the piston cylinders out using compressed air - put a board or similiar between the pistons - the come out with quite a lot of force and can be dangerous if you have a body part inbetween.

Brett San Diego

Great color. Believe it or not, I shopped completely by color when I went looking for a different Porsche (Had a Boxster). I'm a huge fan of the light non-metallic blues (Mexico, maritime, gulf, riviera, royal). I thought for sure I'd end up with a royal blue SC. My second choice was orange. I almost bought a maritime blue 968 long distance but then found my orange 78 911SC locally last October. I've never seen crystal blue. Looks sweet. BTW, paintscratch.com shows crystal blue from 1968-1971, but I don't know how reliable their historical color chart is.

And, I wouldn't touch your car with track modifications. It's a unique car worthy of preservation. Buy one that's already been beat up for the track.

Good luck with the rebuilds. I was setting out to do the same thing on my SC when I found one of the pistons was frozen in one of the front calipers. Since I'm in this car for the long haul, I decided to just buy all new front calipers. Then, I said, what the hell, I'm already in big bucks on the brakes, why not pay a professional to rebuild my rears, so I bought rebuilts from Vertex.

Brett

pgrunwald

Thanks for the nice comments! I was not looking for a special color or even a Targa, only a G-50. I spotted the car on eBay but it was local to me and after it didn't meet the reserve I was able to get a great deal. It has turned out to be a perfect first Porsche for me! The car is very solid, gets a lot of attention, and it is still faster than my driving skills.

I have pretty much decided that that this brake update will be the extent of my mods for the track other than tires. I have 16" wheels on it but I also got a set of 15" wheels (original) with the car. The PO had track tires on those rims, I just wanted to learn how to drive stock first. I have given serious thought to putting in a cage and whatnot but it is a Targa and I don't want to ruin that, I agree with keeping it close to stock and pretty. The Targa has also been great for the wife acceptance factor (WAF)!

That said, it is a Porsche and I expect it to look good going to the track and go good at the track. The PO put on some track pads that performed pretty good but the current rotors are shot at 65K. This brake tuneup only costs a few hundred more for the slotted rotors and pads. Doing the rebuilds and work myself is also a reason I bought a G-50 and not a 90's car. I work in high-tech and getting greasy is therapy! I have fixed a lot of little stuff on the car already and it has been fun.

Again, I appreciate all the help here on the board!

Paul

pjc

Paul,

If you don't have access to an air line (not everyone does) reconnect the short brake pipe to the caliper and clamp an ordinary foor pump to the other end - it will fit over the connector perfectly. Jeremy's advice is sound too - piece of wood between the pistons will stop damage to caliper and you!

Just take it easy and all will be well.

PJC

Brett San Diego

You should consider some suspension upgrades if you will do some track work, and lower and corner balance. I was mostly referring to anything that would change the unique exterior factory look. You can't see the suspension from 10 feet away. Just don't mess with that beautiful body!

Brett

pgrunwald

The car has been lowered, balanced, and has weltmeister front and rear sway bars as well as the tower brace!

Hopefully I will be able to learn how to drive fast and still keep it shiny-side up!

Paul

rbcsaver

See this previous archived post and the tools I made for the job.
DO NOT split the calipers.
https://rennlist.com/forums/911-forum/166494-sticky-caliper.html
regards,
Steve