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Clutch Cover Bolts
Furyous - 14/11/12 at 07:04 AM

What kind of bolts should I be using to mount the clutch pressure plate to the flywheel? Obviously it's not somewhere to cut costs on with cheese bolts, but Mazda have said the official bolts will be £5 each.

Mr Whippy - 14/11/12 at 07:12 AM

Their probably fine thread too and use locking compound, I think they are higher than 8.8 though I have only ever used the ones that came with the engine, there's usually 3 pins that take the load too. Unless you have a huge engine I think overall there is little load per bolt

£5 a bolt is very greedy, probably only cost 30p each for them to buy

[Edited on 14/11/12 by Mr Whippy]

britishtrident - 14/11/12 at 08:06 AM

Grade 8.8 is fine as is 10.9 the bolts aren't particularly highly loaded, normally OEM bolts come ready painted with blue thread lock.

Balance is the most important consideration manufacturers bolts are likely to have a tighter weight tolerance than normal run of the mill bolts, this is no problem just check the bolts are close to the same length and weight.

The clutch pressure plate to flywheel joint basically is the same as a flange joint drive in that drive is transfered by static friction between the two surfaces. The dowls don't transmit drive they are fitted to accurately centre the pressure plate.

Furyous - 14/11/12 at 08:11 AM

Thanks for that. The cover is currently held in place with some 8.8 hex head bolts so if they're ok I'll put some Loctite on and torque them up. Should I use washers/spring washers?

Mr Whippy - 14/11/12 at 10:13 AM

quote:
Originally posted by Furyous
Thanks for that. The cover is currently held in place with some 8.8 hex head bolts so if they're ok I'll put some Loctite on and torque them up. Should I use washers/spring washers?


Yeah all the ones I have ever done had spring washers, really don't want them to come loose and there's no way to wire them or inspect so best to do all you can

britishtrident - 14/11/12 at 06:02 PM

Spring washers worked well in this application but spring washers are well out of fashion these days manufacturers use flange head bolts, These days clutch pressure plates are often held with male torx flange head bolts.