From digest.v7.n1448 Sat Apr 4 14:40:50 1998
From: Steven J Bernstein <stevenb_at_garageboy.com>
Date: Sat, 4 Apr 1998 13:44:21 -0500 (EST)
Subject: RE: <ALL> Caliper Guide Bolts

Steve D'G clarifies:
>>Pete is correct...there is generally no need to replace these. They
>>should be cleaned when removed and a bit of high temp anti-seize put on
>>them prior to reinstallation. I have had people cross thread & break
>>them or use a worn allen key and round them out. I sell them for $10.00
>>each (a little cheaper than the dealer) and it's probably not a bad idea
>>to keep 2 spares in your tool box at the track or in your garage. Fixed
>>and Girling calipers do not use this part. SD
>>=========================================
>>Steve D'Gerolamo - The Ultimate Garage

Yes, sorry, folks for the previous bit of misinformation. Thanks, both Pete and Steve D'G. I'm now looking at the shop manual, and indeed, it says "renew if necessary" but it doesn't say what "necessary" means. I don't recall where I thought I read "renew every time" (perhaps on the instructions from ATE in the factory brake pads box? - I'll have to check). So how do YOU define necessary? Every 100k? Every 5 re-torquings? In MY opinion, as long as they're not rusting, and clean up fine every time, re-use them. On my old E28, some are original with 289k miles. But they're clean. 8^)

Some rabid type piped in with something like "I musta removed these 40 times in the past year and I've never had a problem...".

So, clearly, his experience falls outside the category of what 90% of BMW owners go through. While he may be correct, his experience may not be as relevant to the rest of us. The accumulation of brake dust is the most damaging factor in your brakes, and when you're taking them apart only once a year (ok, even up to 5 or 6 times for non-rabid track-goers), you're dealing with a different set of factors.

The most important point here, regarding your brakes, is cleanliness. Steve D'G reiterated that in his post. Clean, clean, clean. My friends make fun of me because while I can theoretically do a pad replacement in about 5 minutes per wheel (7 minutes with my eyes closed), I put the car up in the air and putter and clean all the brake components carefully before reassembly. It takes awhile.

I remember snapping one, yes, even with a torque wrench, because on my old E28 after 240k miles, one of them was simply ready to go. It happened on a Sunday afternoon a couple years ago, and I frantically found a small parts store that had a "replacement part". It cost $6. I used it, but I bought one at a dealer the following Monday and swapped it in that evening. The quality of the aftermarket bolt was unbelievably poor. There were noticably fewer threads (shorter) and there was so much play in the head with the 7mm driver that I knew I could never get an accurate torque reading. It scares me to think that they're allowed to sell such a low-quality brake part. I trust Steve D'G's bolts are factory.

Now the BMW factory shop manual clearly states "don't lubricate". But, we all have opinions (what's that expression?? 8^)), and I tend to agree with Steve D'G's opinion to use a bit of hi-temp anti-seize. When I had to use an easy-out on the remaining portion of the bolt left in the caliper bracket, it was cake. Because I anal-retentively clean the bolts (and threads) to perfection (and use anti-seize) each time I reassemble my brakes, the easy-out grabbed immediately and the remainder of the bolt spun right out.

It's situations like these that proper mechanic techniques make all the difference to your automotive Zen repairs...

Cheers,
.steve.
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