Missing rear brake caliper bolt and nut

m_thompson

m_thompson

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On my '73 USA 3.0CS, while I was painting the rear calipers today I noticed that one of the four bolts that hold the caliper together is missing. It is one the longer bolts, the one that is closest to the brake pads. It measures just a little shorter than 2 7/8".

W&N doesn't list it. The BMW sites say that it is NLA.

Anyone have a bolt and nut that they would part with?
 
I have an old r caliper that I could take a bolt out of for you. I can't remember but does it have a torx style, Allen head. We'll go from there. DCG
 
dascoupeguy said:
I have an old r caliper that I could take a bolt out of for you. I can't remember but does it have a torx style, Allen head. We'll go from there. DCG
Click to expand...

It was probably made before TORX was invented, so it is just a standard hex socket. In my caliper there are two different length bolts. I need the longer of the two, the one near the pads.

I will happily pay for the bolt, packing, and shipping.
 
It may be the special torx-like bolt mentioned in PMB Performance's rebuild thread a while back. He said it's important to get the correct fitting tool.
 
bolt name

they are called RIBE, and indeed they are collectable. They are sized M7 (and i believe for the front M9) which is not produced anymore with this specific RIBE head shape. There is a large fastner manufacturer in my city supplying even some german car brands where you can get nearly anything.... but not these :(
 
It is a normal 6mm Allen (hex) socket.

Since the same caliper was used on the 6-series I would not be surprised if some rebuild calipers used more modern fasteners.
 
My E12 M535i has regular hex heads in the front and socket head cap screws with nuts in the rear. Funny this thread came up since I have already split my calipers and am sending the halves and spacers and what not in for yellow zinc plating. What I keep reading is that the bolts are stretch bolts. Fronts are M9 and rears are M7. I can't find replacements anywhere (and I'm flexible on the head style), but I keep hearing of people reusing them, and that's also what the PMB Performance How-To suggests as well. Walloth and Nesch has front bolts available, and they do have the necessary bolts for my M535i front calipers (80mm length), but they say the rears are not available.

From what I've seen, there are limited M7 and M9 fasteners available, but none in the necessary lengths.
 
I bought a remanufactured rear caliper on eBay for $86.95. If the bore looks OK, I will replace the seals and piston with the ones that I got from W&N, paint it, and start on the front calipers.
 
"Walloth and Nesch has front bolts available" Why can't you grind and then re-thread the M9 to M7? I rebuilt mine years ago and use the same bolts with no issue.
 
The eBay listing says that the caliper fits 3.0CS, 3.0CSi, 3.0Si, Bavaria, 530i, and 528i. The $50 eBay caliper was actually for a 2800CS with the non-vented rotor, not a 3.0CS with the vented rotor. It doesn't have the spacer between the caliper halves so the bolts are too short. The bolts on the rebuilt caliper are the new RIBE ones.

So now I am back to begging for a bolt from an old caliper, trying a Nugeon caliper from Bavarian for $86.95, or buying a new caliper for $287.95.

dascoupeguy, did you find your old caliper?
 
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