Just rebuilt my front calipers
 

Kind of a tedious job. I've been experiencing uneven pad wear and my front RH tire locks up before any others, despite a corner balance. I'd sometimes get a hum in the steering wheel that a one toe tap on the brake pedal quieted. So I figured I'd rebuild them and see where that gets me.
"Rebuild" is maybe too strong a word. It really is simply to replace an o-ring and a dust seal in each piston bore, and scotch-brite the pistons and bores themselves to remove any gunk deposits.

Getting the dust seals off requires a punch or small chisel to deform the seals metal outer ring so you can lever it out. The o-ring comes out with a small dental pick. The job also requires a $50 jar of special Porsche-only caliper grease made out of the tears of Mermaids. I now have enough for several lifetimes.

Old pads right after a track day; note the uneven wear:
https://lh3.googleusercontent.com/-U...0_15_13_38.jpg

My dust seal removal tool:
https://lh3.googleusercontent.com/-H...B3_22_%2B6.jpg

The caliper out on the workbench. Getting the pistons out requires air pressure applied to a bleeder port. A block of wood in the caliper where the rotor would be prevents damage to the pistons when they shoot the hell out like rifle shots. Be sure to put another hand on the brake line or you will have a geyser like I did. Brake fluid literally hit the ceiling, I'm embarrassed to say:
https://lh6.googleusercontent.com/-D...B3_22_%2B5.jpg

Caliper with new o-rings installed, old o-rings and old dust seals deformed from removal next to it:
https://lh4.googleusercontent.com/-O...1_+3_22_+5.jpg

The aforementioned caliper paste:
https://lh6.googleusercontent.com/-4...1_+3_22_+6.jpg

Also put on some Pagid blue pads, and new Zimmerman rotors. Unfortunately, it is the dead of winter up here in NY and besides snow ice and 20* temps, we have about 1/4" of road salt on the roads, so I cannot take the car out and bed in the pads and report on my results.
https://lh6.googleusercontent.com/-s...1_+4_22_31.jpg

https://lh4.googleusercontent.com/-m...1_+4_22_31.jpg
I am the best thing that ever happened to this car. ;)

Nice job, may I ask where you got your garage floor tiles? My epoxy coat is looking bad and I've been looking for an alternative, yours looks slick!

Well done Grasshopper !!!!!

Cole

Nice job Ken. Are those Pagids the "street sport" pads, or something else? I ran those on my car until they got used up on the track. They work and wear a lot better than street pads on the track. I am now using Pagid yellows, which are supposed to be even better.

Am envious of your ability to do winter projects on the 930. My workshop was wrecked by Sandy storm surge. Finally got the contractor started on rebuilding the space this week, so hopefully I will have some time to tinker before the driving season.

What is the difference in the $50 bottle of Porsche Caliper grease vs the $8 tube Pelican sells (that i used)?

The Porsche grease has been blessed by the Porsche gods.

Few follow ups- one thing I didn't mention was cost other than the grease. The four o-orings and four dust seals were $108 PER SIDE, so $216 for both front calipers. Pretty steep for a few grams of rubber. Porsche...

Piston grease is Piston Lube 000.043.117.00 From my reading here, "Porsche specified this grease for better seal 'roll back' and less pad knock off. The influence of caliper assembly paste on seal performance will last for a significant time and give a sharper response and generally good 'feel'."

The floor tiles are made by Swisstrax. Ribtrax Garage Tile - Garage Floor - Garage Flooring - Rubber Floor Tiles
It looks great and is easy on the feet, but a surprising amount of little stuff can make it through the ribs and require pulling a section up to get it. I would get the solid ones if I did it again.

J- yes, the Pagid blues are a relatively new street sport compound. Hopefully they can withstand an HPDE or three and still work when cold for the street. I've heard the yellows are fantastic but need hest in them i.e. track only, which is not my use case for this car. Best of luck with repairs. Build it better!

Research and Development costs money:)

Hey Ken,

How are the refreshed brakes performing? I seem to have some sticky pistons so I think its about time I perform this task on my car...maybe you'll let me have some of your "mermaid tear" caliper grease :D

Oh they came out great. No pulling, pulsating, or humming in the steering wheel anymore... However the front right tire is still the one that wants to lock up first when braking to the limit of the tires. Corner balance is dead on. I'm redoing my suspension in another thread for other reasons but maybe it will help here too?
Send me your address and I'll get the grease out to you. Or I can meet you at Monticello at Bring-A-Friend-Day and I will personally deliver it. ;)