Front Discs, Key retaining screw issues

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Oct 8, 2007 | 04:45 PM

seventyseven250

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From: Calgary Canada

Front Discs, Key retaining screw issues

This is on my 1977 F250 Camper Special, with Dual piston calipers.
I was replacing my front Calipers, Rotors/hubs and brake pads, and after sever diffferent attemps, it looks done, except for one problem. I managed to break off the "key retaining screw" on one of the caliper cages. See diagram for details.

Now, my questions are:
1) Can I run without this retaining screw? or will the key slowly work itself out and I'll have a catastrophic loss of the caliper?
2) How can I get the broken part of the retaining screw out?

I have a set of bolt extractors, so I'll look around for them. In the meantime, I would love some advice from the brake gurus here.

Oct 9, 2007 | 11:40 AM

Red Monkey

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I'm not a brake guru or any other type of guru but here are some suggestions.
I would try a 'left hand' drill bit and some PB Blaster on the broken bolt then try the extractor. But, the PB Blaster will NOT be good for your new pads. Be VERY careful with the extractor as they are hardened and very brittle. If you brake one off you have compounded your problem.
If that fails I'd replace the caliper. The cost of a 'loaded' replacement caliper is a LOT less than the cost of brake failure!!!
Did you try to tap the key out after the bolt broke? I'm not sure if the bolt head holds the key in place or the bolt shank.
I guess you could just drill the hole out and re-thread it using a tap as a last resort.
The EZ route, as well as less time consuming, would be to buy the replacement loaded caliper and be done with it.
Good luck.

Oct 9, 2007 | 05:09 PM

seventyseven250

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From: Calgary Canada

Quote:

Originally Posted by Red Monkey

Did you try to tap the key out after the bolt broke? I'm not sure if the bolt head holds the key in place or the bolt shank.
I guess you could just drill the hole out and re-thread it using a tap as a last resort.
The EZ route, as well as less time consuming, would be to buy the replacement loaded caliper and be done with it.
Good luck.

I just put a new caliper on, the place where the bolt threads into is not part of the caliper, I belive it's part of the spindle assembly.
I can remove and re-install the key just fine, the bolt broke in the threaded part and it does not interfere with the key.
I guess as an absoloute last resort, a person could spot weld the key in place against the bracket and leave the caliper floating. that's not my first choice, but it would be safe.

Oct 9, 2007 | 06:18 PM

rebocardo

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From: Atlanta GA

You can't spot weld the key, it moves. I imagine you broke the bolt by tightening it, so it will be a hassle to get out. Just use a steady hand and drill out the center (start at 1/16) if you can't get a vise grip on it. Then once you have a shell left, use a pair of needle nose to twist the sides down and pull it out.

Oct 9, 2007 | 10:06 PM

seventyseven250

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From: Calgary Canada

The key doesn't move, it's held in place by the key reatining bolt. The caliper slides on the key.
I think . . . .

Oct 10, 2007 | 02:38 PM

rebocardo

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From: Atlanta GA

Take the wheel off the good side, have someone step on the brake, then tell me the key does not move.

> The caliper slides on the key

I never said the key moved left to right, eh? There is a certain amount of movement when you slam on the brakes, close tolerance does not mean rigid

:- )

Last edited by rebocardo; Oct 10, 2007 at 02:40 PM.