OldGuy

Now I know why Porsche made the forged plate wheels. To cover up the mediocre brake calipers. How many pistons are in the early 928 front brake caliper? They look like the old one piston BMW calipers that BMW put on the M3s. Is there an uprade?

is there an AC recharge kit for the early 928s or is there a conversion kit?

thanks in advance! I got NO results on my Searches, didnt even come close

Rob Edwards

OG-

Early calipers are single piston, yes. Dunno whether the brakes on a Weissach are the single piston 'S' brakes or not. The upgrade is to later S4 4-piston calipers, but that requires various combinations of 993TT rotors and adapters, or S4 spindle swaps and mounting adatpers.

64 results if you search for 'S4 caliper upgrade'.

There are also many threads on the subject of A/C recharging. By kit, do you mean a kit to convert to r134a, or ??? What symptoms are you having with the A/C? (other than a lack of cold ) If you know it's low on freon, then (of course) there's a leak- are you interested in repairing the leak, or just topping it off and hoping the leak is small? We're here to help, just need more complete symptomatology.

For an outstanding guide to diagnosing the 928 A/C system, you can start with Wally Plumley's writeup. Go to 928gt.com, click on 'tips/links' in the lefthand column, then 'Wally's World', then 'the HVAC system'.

Landseer

S brakes are very good for street use. Rebuild kits are simple and total about $40 to do all four corners. The pistons and bores rarely seem to score. I've refreshed 6 sets in the last couple years.

Dave928S

I didn't think that S brakes were up to the job so upgraded to S4 front and rear on my 82. I stayed with the S suspension, changed to early spindles and adaptors, 993TT rotors and S4 calipers up front .... S4 calipers with spacer washers, and S4 rotors at the rear .

I guess it comes down to individual preference, and what you regard as enough braking, but I thought the standard S brakes were a bit average for a car which is so good in other respects.

Landseer

Ahh. Using pre-S spindles? Any way to do it with S-spindles?

Its true, I'm a lightweight when it comes to pushing the cars.
With kits, pads, rotors and hoses there's been plenty of brake for my driving style on the road.
Track would be different (unless my wussieness carries-over).

porschedonald

DD

Dave928S

After I get out of my 4WD daily driver, every day's a track day for me Chris

No .. you can't use the S spindles, because the bolt centres of the S4 and S caliper attachment bolts are very close in centre to centre dimension, and won't give you enough room to have the mounting and caliper bolts going in opposing directions without clashing.

The early spindles have smaller centre to centre caliper bolt threads, and are sufficiently different from the S4 to allow the bolts to pass in opposing directions in the adapter block without clashing, or giving a weakened adapter block junction point.

The only trouble with the early spindles is that they only have two dust shield attachment points instead of four as on the S spindles.

I guess you could use S spindles if you machined an offset adapter block to stop the clash by rotating the caliper a few degrees or more ... but I haven't looked at that closely.

Lizard928

Or possibly using 355mm rotors thus pushing the caliper further out giving more meat for everything there....

SeanR

The more you reveal about that car, the less of a service you are doing it.

Dave928S

Mmmm ... that's a good thought.