worf928

Carl Fausett

Not to my knowledge, no.

ROG100

The "Killer" for the DIY caliper rebuild is the cost of the caliper seal kits from Brembo and some are now over $100 per piston. Coupled with new plates as Carl says "gets expensive real quick".
When rebuilding a caliper how often do the pistons need replacing?? All the time or just the odd one due to corrosion?
The seals are relatively cheap but adding the piston to the kit is the large part of the price.
I replaced the seals on an S4 set but reused the pistons a few years back - you can buy the seals & dust boots from https://www.zeckhausen.com

Carl Fausett

In my experience, the piston needs to be replaced anytime the protective coating on the outside of the piston has been worn or scratched through. Often the cause is a bad sweeper on the dust boot allowing dirt to scratch the piston, but water in the brake fluid can also corrode the piston and piston bore from the inside.

Thats a good link - thanks for posting it.

DonaldBuswell

Perhaps these incidents were folks eager to be hands-on all aspects of their car? I can tell you I media blasted my Brembo 993 calipers with NO issues, but, I'm a professional media blaster and kept them assembled and blasted with plastic, which, one reason I frequent RL is to educate fellow enthusiasts on media blasting and what works and what does not work and what should happen and should not happen and techniques and tactics to employ and equipment and materials etc.

DonaldBuswell

I bought the seals brand new, same ones seen above for $7.95 each.

ROG100

Donny - mind sharing where you bought the seals from as they are not easily available on there own.

DonaldBuswell

I lied, they are $7.65 each, I also got the other size seal too for my rear calipers and the smaller piston on the front 993 Big Red, 3 different size pistons. http://www.hrpworld.com/bre-20487248...dust-boot.html

docmirror

^^^ Those are the dust boots, not the cylinder seal. ^^^

Seal kits, minus dust boot. https://www.rockauto.com/en/catalog/...epair+kit,1720

Per caliper, F or R. Order dust boots separately.

DonaldBuswell

docmirror, please explain what a 'cylinder seal' is? To qualify my interpretation I have 993 brake calipers on my 928S4. I have completely gone thru them and rebuilt them. Meaning, take them down as far as possible. They are block type, two piece left and right, bolted together with no gasket, just a friction seal with no fluids passing thru each block into another block, this is handled by the brake line from one block to the other block. Each block has 2 cylinders and each cylinder has a piston. The 993 set up has a total of 3 different size pistons and thus different size seals. There is no cylinder seal, there is a dust seal which encompasses the Piston and holds the piston in place while serving to keep dust out. I payed between $7-13.00 per seal, all my pistons were serviceable with no scratches and or scars or rust damages from water. So, please, explain what you are exactly talking about because I do happen to know what I am talking about on these (993) brakes - which, could be different than the 928 organic brakes.

docmirror

A dust boot keeps brake dust from contaminating the hydraulic components of the brake caliper. A cylinder seal keeps the hydraulic fluid from leaking past the piston. That's as exact as I can be without charts, diagrams, and part numbers. If the link you provided for the 993 caliper is the only seal you need or want, I'm ok with that. Everyone else in the thread is discussing 928 brake rebuild. If it is your position that this dust boot you linked will work as a hydraulic seal on the 928, I would say that is questionable until tested/proven.

edit; Rockauto.com shows similar kit for 1998 911(993). https://www.rockauto.com/en/catalog/...ke+&+wheel+hub

Caliper repair kit, showing cylinder seals, and what appear to be dust boot. In fact, one of the PN cross-references to a 89-95 928.

DonaldBuswell

I figured you meant as much, I understand this concept. But, my Pistons do not have a seal, there is a seal/dustboot combo which is very flexible and a stout little bugger. No other seals are in these calipers. As you can likely appreciate, the devil is in the details.

DonaldBuswell

docmirror

Ok. Suncoast, rockauto, FCP Euro disagree with you, but again - I'm ok with that. All show separate cylinder/piston seals, not just dust boots. A hydraulic piston without a seal would be a first for me, but surely I am ready to be schooled.

https://www.suncoastparts.com/product/92835191910.html

https://www.fcpeuro.com/products/porsche-disc-brake-caliper-repair-kit-911-54443003237

The only thing I wanted to point out with post 39 is that those with 928 brakes will not be ok by just replacing the dust boot in your link. They(and the 1998 993) require the cyl/piston seal. If you have something else, that's fine - no panties wadded up here.

DonaldBuswell

I too share your questioning, this is why I asked you all this. I do not come here to school you or anyone, please know that, frankly, most Porsche owners are a prickly lot, like the Corvette owners out there. However, here on RL there are a good enough number of smart hands-on people to keep me entertained. There are no other seals other than the one dust seal which has dual function as seal and dust boot. Why would I not be truthful? I don't operate herein needing validation or other silly mannerisms. I like and respect hands on analysis, and those whom actually do the work in question.