Brake caliper bolts

[CWXC70]

I think I'm right in saying the hydrogen embrittlement is an issue that affects electroplated bolts, self colour should not be affected. If the plated bolts are correctly passivated after plating the hydrogen embrittlement should not occur.
When we were manufacturing calipers we bought only socket cap screws from Unbrako as these were the only ones we felt we could trust to have been plated correctly. We never had any failures luckily.

[Honest989]

Hi guys. What was the outcome of this thread and does anyone have a shopping link for the bolt?

I recently tried removing a caliper from my car and rounded one of the heads in the process. I don't actually know the correct bolt for the caliper as IPD USA is offering front caliper bolts that are M12x35 but they're based in america and I'm not waiting that long for a bolt.

[leftfootleashed]

I had some trouble finding M10x30mm hex head bolts, as opposed to fully threaded set screws. I took my seized caliper bolt out last night with a bolt grip and there is about 20mm of thread.

After the discussion above about hydrogen embrittlement, I went for 8.8s. I've just bought 10 from eBay after asking the threaded length from the seller: 25mm.
These: http://www.ebay.co.uk/itm/2907769874...%3AMEBIDX%3AIT

I'd be happy to send you one or two FOC if you want, I don't need 10! Obviously, you fit them at your own risk. I've decided that I'm happy that they are a safe replacement for my brakes. You have to make that call for yourself too.

[Honest989]

Well, can't harm. I'm struggling to find the correct bolt in any case. I'll PM you with an address

[Honest989]

Hmm, apparently I can't as I don't have 30 posts!


Thanks for this - the current bolt is wedged in there. I can either take it to a garage to get it sorted at £83+ or i can do it myself at the price of the bolt grips...

Just to be an extra pain in the arse - any chance of a quick post? Ideally I need to try and get this done by Tuesday next week.

Let me know how to give you my address and I'll pass it across

[geoffo]

...in the form of a parts diagram and a parts list (attached I hope!) ......its possible to weld a socket onto the bolt head and undo it - at the cost of the socket.....

[leftfootleashed]

Drop me an email: left foot leashed (all one word) at gmail dot com.
I meant to say, I ordered them today so don't actually have them yet. They've been marked as dispatched and coming first class so should be here Saturday, maybe even tomorrow. Even if I post them Saturday, first class should get there by Tuesday. I'll do what I can!

[CWXC70]

Sorry but 8.8 do not have sufficient tensile strength to be used as caliper mounting bolts. Fine for low stress applications but not on brakes. Check what any standard caliper bolt is, you won't find any 8.8s

Call these people
http://www.tridentracing.co.uk/racin...rcial-range-18

[crogthomas]

Why not just get the correct bolts from Volvo?
If there isn't a dealer near you at least one of the traders listed on the forum (FRF) will accept payment by phone and post them out to you next day. I suspect they're the same bolts as used on many other Volvos, so will probably be in-stock.

[leftfootleashed]

I think there's very minimal risk in using a grade 8.8 bolt. But just to convince myself, I did some maths. This probably won't convince anyone else, but here you go:



That's less of a safety factor than I would have designed for, but I've made some pretty conservative assumptions, like the whole weight of the car being on the rear wheels under braking.

Geoff, try not to get too excited ;-)