ivangene

yea, I didnt get that comment either

glad you are back on topic Ed

ricster

I'm going to re-bleed them after I put a few miles on her

Ed Hughes

Hehehe. I've got a theory on that.

whalebird

What kind of fluid are you using. I found that ATE super blue would give a firm pedal, but the first push of the pedal travels a bit further. I have seen this in all of my personal cars(including Ford truck) and had seeveral customers comment on it. I use ATE in everything I have right now and noticed this every time if flush the system.

ricster

I am using Ate blue

whalebird

let us know after a few shake down miles.

sig_a

Viscosity of ATE Blue is 1400; Pentosin Racing is 1800; Castrol SRF is 1200. Numbers measured at minus 40 degrees C.

Just completed rebuild of my four calipers on 911. Pressure flushed using two liters of ATE blue to purge old fluid and free up trapped air in system. Finished flushing, then filled system with higher viscosity Pentosin Racing. Results: surprisingly hard pedal. Higher viscosity helps firm up pedal, and new cylinder seals had very little to do with spongy pedal. In my case it was air trapped in cylinders after rebuild.

May911-85

this thread was great help! rebuilt my calipers this past week and this content was as good as a manual!
thanks! chuck

ricster

Hello All,

I have finally got a firm pedal. It basically took some miles and heat into the system to get the new seals broken in. Pedal is nice and firm now. Go figure

ivangene

I recently rebuilt my fronts and the pedal was solid from the word go - your thread had me worried, but for whatever reason mine did NOT do what yours did???

I found a leaky bleeder too - keep your eyes on those. at the next pad swap I might rebuild the rears just for good measure - dont know if they have ever been done.

Glad yours are good now

pmgoodwin

I just rebuilt the front calipers on my 87 Targa w/930 brakes. After I got them done I thought they were spongy. but after driving them on the track they weren't spongy at all. I was just so used to the stiff pedal with no travel that when they worked properly they felt spongy.

Paul

ricster

supposedly talking to a friend of mine who does a ton of work on Porsche race cars said that the seals basically "rollup" and pull the piston back into the caliper farther than it should, so you either use this special caliper lube (which I did not use) or you drive it for a bit and with repeated heat into the system causes the rubber to not pull the piston back into the caliper.

ivangene

well that explains it for me - I applied Krytox to the seal before installation (I put krytox on ALL seals and most bolts/nuts) - brakes were good to go first stop

pmgoodwin

The caliper-seal combination is designed to pull the pads away from the rotor. you don't want them rubbing against rotor. I think that lube is for inserting the piston and not for normal operation.