front caliper cast in pin on early 914, What if they is broke? Options

[dmenche914]

On an early 914 4 cylinder front brake caliper, there are pins cast in tot eh caliper halfs for each piston. They are missing (ie broken off) on the caliper.

Any one know how they work? (the part in the piston that they "guide" is free floating).

Anyone experience running with them broken off?

I haven't see this type of cast in pin on other cars calipers.

Thanks

[davep]

That is part of the retraction mechanism. When you put your foot down, you force the piston out against the pad and rotor. This moves the piston along the pin, and stretches the O-ring in the bore. When you remove your foot, the pressure is released and the spring in the piston pulls itself back on the pin, and the O-ring relaxes to normal shape. Both serve to restore the venting clearance between the rotor and pad on the front calipers. Without the venting clearance you get unnecessary drag and pad wear.

You can run without the pin, but you should expect a little more drag and pad wear. I would replace the calipers with good ones. They are cheap enough. I have never seen broken pins in my 25 years of rebuilding calipers. I think someone did it on purpose, and I can't think of a good purpose.