I'm after a set of clutch bolts and would rather just head down to the bolt shop rather than ship in 'official' ones from the US. Does anyone know the exact specs? Best guess I have so far is M8 15mm long and 1.25mm thread, is this right? Thanks
I would use REAL ones. The clutch cover bolts are only a little special. Someone here will be parting manual car. Ask around a little further
Biggest ticket item parting out a manual car is the manual conversion kit though. How special is only a little special?
They are only torqued to 40 Nm so not too special. Dunno maybe I just like to use the right bits. They have a very chunky and longer head than normal bolts. They have a retained flat and spring washer from memory. But I spose you could could use black high tensile engine bolts, flat and spring washers without an issue.
Use black recessed hex head bolts (Unbrako type) with those conical serrated type spring washers, German name of some sort. That's what Race Clutch use, a touch lighter than ordinary bolts too plus those washers are the ducks guts.
Thanks guys, Graham, I'd be getting the real deal if it did not involve shipping from overseas. I figure if I get some that are the right size and shape with the right thread and strong enough it should be as good as teh real thing. Can anyone confirm the specs?
Clutch pressure plate cover yeah? I had all the oem bolts but was one machine washer short. Pita. I ended up just using some m8 x 20mm 10.9 plated bolts from work with other machine flat washers i had. I used 20mm as the washers were thicker them oem. I double checked the flywheel thread depth so not to have the bolts bottom out without not having it torqued down correctly. Could have used 16mm long ones but compared to the oem bolts there wasn't as much thread biting together. So again a reason for going that bit longer. In the long run. Double check your thread depth. Add the thickness of the pressure plate cover, plus the washers thickness and go from there. Just get 10.9 bolts from your local and suitable washers then go from there. If not you can have my oem stuff but you'll have to source an extra washer.
As an aside, but on this topic, using bolts longer than necessary in any application wont really hurt, but is actually pointless. The amount of thread engagement required for bolts (depending on the thread pitch) is actually a certain fraction (escapes me atm but its well LESS) of the bolts threaded diameter and a good guide to choosing bolt length is to add up the components as described by Sanouske and then leave the same number of threads exposed as a standard nut! So for an M8 bolt, your talking around 6mm of thread engagement.....!!!! The thread will only pull out if it is already badly worn or damaged from previous cross-threading/overtightening. You might be surprised how LITTLE thread engagement is actually required to exceed the yeild strength of the bolt material. So using the longest bolt possible without "bottoming" actually achieves nothing as the bolt will always break between the end of the unthreaded shank section and just above the first engaged thread of the job if its yeild strength is exceeded by overtightening. Pete, dont get too dazzled in science over this. Its a clutch cover FFS and the bolts are done up surprisingly loosely being M8. additionally, there are 9 of them so thats a lot of areas of clamp along with 3 locating dowels. Super-duper high tensile bolts with funky weird arsed washers and so-on are simply not necessary, not even desireable when you factor in the very light tightening torque of a standard M8 bolt. This is why I reccommend some plain black 15mm capscrews (aka: socket head/Allen head/Unbrako... blah) and some split washers form the local bolt guy for a few bucks and your grinning. Newhoo at ease gentlemen!! E
So I'm resurrecting this thread as it had some good info. Can I assume that the clutch bolts are M8 15mm long and 1.25mm with 3mm washers?
