E28 Brake Callipers

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   Right. Need to hear the right answer here for the sake of both my
wallet and my sanity. Have finished fitting new brake pipes to the 525,
and went to bleed the system. Upon contact with a spanner, two of the
bleed nipples sheared off flush with the callipers. I knew they were a
bit corroded, but they had been soaking for hours in penetrating fluid
and I was very careful! What I really need to know is are these
callipers now scrap, or can they be drilled out and retapped? Please
don't say I need new callipers!!

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Doive Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Really Senior Member II Joined: 09-February-2005 Location: Clinging to a turbine, Hexham Status: Offline Points: 1212	Topic: E28 Brake Callipers Posted: 19-March-2005 at 14:44
	Right. Need to hear the right answer here for the sake of both my wallet and my sanity. Have finished fitting new brake pipes to the 525, and went to bleed the system. Upon contact with a spanner, two of the bleed nipples sheared off flush with the callipers. I knew they were a bit corroded, but they had been soaking for hours in penetrating fluid and I was very careful! What I really need to know is are these callipers now scrap, or can they be drilled out and retapped? Please don't say I need new callipers!!
	1987 BMW 525e Lux Auto (sadly deceased) Get Firefox - Ditch Hopeless Inertnet Exploder www.doive.co.uk

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Jim525d Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: 14-February-2005 Status: Offline Points: 45	Posted: 19-March-2005 at 16:14
	Options: 1. Drill the bits out. When you get the drill size right you can destroy the broken inner bits without wrecking the threads in the calipers. The disadvantage here is that you will fill the calipers with seal destryong swarf that will need VERY CAREFULL flushing out. Not recommended but cheap. 2. Drill a pilot hole in the bleed nipple big enough to get an "easy out" in to. These have a rough, left hand thread designed for removing sheared bolts. Disadvantage is that they aren't 100% effective, on a soft bolt thay can just spin round in the hole. How to here 3. If you know a welder, try this. 3. Scrap the calipers and go get some Brembos. Crash your credit card here. Good luck. Jim Edited by Jim525d

Doive Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Really Senior Member II Joined: 09-February-2005 Location: Clinging to a turbine, Hexham Status: Offline Points: 1212	Posted: 19-March-2005 at 16:34
	I have considered drilling out the nipple carefully and then running a tap through to get the rest of teh crap out, but I'm so aware that the caliper will be filling up all the while with swarf. Maybe I could pull the pots out as well and hopefully all the swarf will fall out. Or I could blow it through with a compressed air line I suppose. May have to try this first, as I don't have the cash to go buying new calipers. The Brembo ones look great, but erm.... no thanks! The ones I have work fine when they are intact.
	1987 BMW 525e Lux Auto (sadly deceased) Get Firefox - Ditch Hopeless Inertnet Exploder www.doive.co.uk

Jim525d Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: 14-February-2005 Status: Offline Points: 45	Posted: 20-March-2005 at 02:46
	I'd take the pistons out and remove the calipers if you are going to drill them. Only way to guarantee you get all the swarf out. If you get the right size drill, you can drill out the minor diameter of the nipple thread without touching the caliper thread. You can just pick what's left of the thread out at this point. Take care not to drill too far though, the bleed nipple seal is at the end of the hole. There is a real cowboy fix and that is to bleed the caliper by using the hose union.... Good luck. Jim

Brucey Members Profile Send Private Message Find Members Posts Add to Buddy List Really Senior Member II Joined: 07-March-2004 Location: United Kingdom Status: Offline Points: 744	Posted: 20-March-2005 at 17:14
	You can bleed the cailper through the hose union and do a good job of it if you work the caliper piston back and forth with a 'g' clamp or a set of large grips. If you drill out the old bleed screw, why not do it whilst running compressed air through the caliper (you will need to restrain the piston obviously) at the same time? That way no swarf can possibly get inside it. HTH
	~~~~~~~ Brucey ~~~~~~

Doive Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Really Senior Member II Joined: 09-February-2005 Location: Clinging to a turbine, Hexham Status: Offline Points: 1212	Posted: 21-March-2005 at 12:45
	Well we tried a stud extractor in the hole, and it proceeded to snap off. Joy. And of course it is super-hard steel, so none of the drill bits would even look at it. Think I'm going to take the bodge and scarper solution to this problem, put the calipers back on the car and bleed them from the hose. I don't like doing this as I always want to have everything done right, but the way I feel right now I don't care. Problems are currently like buses, many of them come at once and the calipers are the least of my worries.
	1987 BMW 525e Lux Auto (sadly deceased) Get Firefox - Ditch Hopeless Inertnet Exploder www.doive.co.uk