Stevenwr

Hello I have a 1988 928 and am in the middle of rebuilding my brake calipers. I ordered new seals and dust boots from Roger (928srus). Has anyone else rebuilt their calipers using Centric Parts from Roger? The seals are the correct size but the dust boots appear to be too big and will not go into the caliper. I even tried freezing the dust boots but no go.

skpyle

Hello Stevenwr!

Your 1988 takes the early Brembo scraper type dust seals. I think in 1989, the Brembo calipers went to the larger dust seals like you have.

In my thread here, in post #7, Roger mentions that he stocks all the correct seals for both early and late Brembo calipers:

https://rennlist.com/forums/928-foru...-calipers.html


Good Luck!

Stevenwr

That’s awesome thank you very much.

skpyle

You are quite welcome!

Hilton

I was looking at this a week or two ago as my 87 has them too.. I haven't bought yet, but from what I can gather, these are the scraper seal centric part numbers:

Front Caliper - Scraper Seal type (87-early 89)
Centric 143.37031 (same as 993 C2 - 44/36mm pistons)

Rear Caliper - Scraper Seal type (87-early 89)
Centric 143.37029
https://www.rockauto.com/en/parts/ce...epair+kit,1720

Note the above are from internet research of porsche piston sizes and models, not actual purchase and fitting experience

Might also be worth picking up some of:

Brembo bleeders
Porsche - 930 351 919 00
Brembo 98.8249.20 (includes dust caps)

ROG100

Steven - email sent - sounds like you may have the earlier calipers on your car.

GregBBRD

Pretty good odds that an '88 928 has '88 calipers:

'87 has a 42mm and 36mm pistons. Easy to recognize, because of the different size pistons.
'88 has a 44mm and 36mm pistons and seals only used in 1988.
'89 also has 44mm and 36mm pistons and seals, different than 1988.

GregBBRD

Unless the calipers have been changed on your '87, it should have 42mm and 36mm pistons.
The 36mm pistons use the same caliper kit as an '88.
The 42mm pistons take different pieces.

Hilton

Thanks Greg,

This might be a RoW versus USA difference. I was using Tech Bulletin 4739/41 as my source of info, which has the smaller sizes for the 86 model year.

I know that there are some differences between S4's in USA market and RoW. FOr example, all RoW 87 S4's got the hinged rear wing, not just early ones, as I owned a July 87 production car with it from factory, and have seen several other late '87 cars in person locally, so it may be that the factory used up the '86 calipers on the USA market in '87.

If so, it wouldn't be the first time the USA market got short-changed. All '86 RoW got S4 suspension, etc. - whereas the USA '86's had to use up the remaining stock of old 928S parts for almost 1000 cars, hence there is no "86.5" concept for RoW markets.

You've highlighted there may be a difference here, so before I order bits, the only way to know for sure is to take them off and measure them I've got to take the wheels off this weekend and do all the fluids including brake, so will pop a caliper off and have a look.

Thanks!

ROG100

Caliper Repair Kit - Dust Boots & Pressure Seals - 86.5 (86ROW) to 87 - Front 36mm & 42mm 14337014
Caliper Repair Kit - Dust Boots & Pressure Seals - 88 to 95 - Front 36mm & 44mm 14337015
Caliper Repair Kit - Dust Boots & Pressure Seals - 86.5 (86ROW) to 88 - Rear 28mm & 30mm 14337029
Caliper Repair Kit - Dust Boots & Pressure Seals - 89 to 95 - Rear 28mm & 30mm 14337009
Each seal kit repairs ONE caliper - Dust Boots are replaced by Scraper Ring style Dust Boots.

In compiling the above list I used the actual seal kits with pistons as detailed in 4739/41. They are expensive - circa $100 per piston.
The piston seal and dust boot in the above kits matched dimensionally those in the Centric kits.

Steven and I have determined that the larger black 44mm dust seal is incorrect and new kits dispatched to remedy the situation
All the Centric dust boots have the relative size imprinted on them. The black dust boot in the first picture did not. All the dust boots are gray. This seems to be a rogue seal and kits will be checked in future before dispatch.