brake trouble, front brakes lock when hot Options

[trfrick]

I need some help - I replace the front rotors, calipers, pad, flex line and m/c. Now when I went for a test drive after several hard stops the front brakes get hot and lock up.
After they cool they release.

What should look for?

Thanks
Tom

[Eric_Shea]

can you explain (with pics if you have them) what this mechanism is on the front calipers?

I'll grab PDF's from the factory manual to show everyone when I get to the office.

Think of the toy monkey that ratchet's its' way down the pole only these work in reverse. As your pads wear, these ratchet the piston out toward the rotor. There's a spring in there as well and they're designed to keep a high pedal feel. You'll probably recall seeing a pin in the piston bore or a mechanism on the backside of the piston.

On very early calipers (356, 911 M, S and rear M) these mechanisms were clipped into the piston with a fairly standard c-clip. 914 calipers and later M-Calipers came with this mechanism machine pressed into the piston. All 914 front caliper pistons go through an ultra sonic bath to clean the mechanism because they will not seperate from the piston. Even later calipers (1975 911 front and rear and SC/Carrera) had this mechanism removed and a "cup" type piston was used. This offered slightly better cooling as there was more surface area in the cup style.

Anyway... I'm more concerned now that there is what I would consider significant rubbing. Tom, is it rubbing on one pad set vs. the other; specifically inside vs. outside? Gap should be around .004" or thereabouts. Again, it's laid out in the manual in the same section but, I'd like to look at it before spreading mis-info.