Clutch Bolt help Urgent
Discussion
Diggidy darn it!
Decided to double-check the clutch on my LS7 while I had a chance..
Found one of the pressure plate bolt heads (socket style) had been rounded off by (presumably) the original installer, so went about removing all the bolts and had to drill out this bolt head to check the clutch, but the bolt was surprisingly soft which I did not expect???... (maybe why it was rounded off inside, in the first place!)
Decided a good idea to replace, but what with?
The shank is 40mm, and it looks like M8 threads, and should I use standard hex heads
Advice please on correct spec as I would dearly like to find some before the weekend...
sorry for the urgency..
Cheers
Keith
Decided to double-check the clutch on my LS7 while I had a chance..
Found one of the pressure plate bolt heads (socket style) had been rounded off by (presumably) the original installer, so went about removing all the bolts and had to drill out this bolt head to check the clutch, but the bolt was surprisingly soft which I did not expect???... (maybe why it was rounded off inside, in the first place!)
Decided a good idea to replace, but what with?
The shank is 40mm, and it looks like M8 threads, and should I use standard hex heads
Advice please on correct spec as I would dearly like to find some before the weekend...
sorry for the urgency..
Cheers
Keith
Hi Keith, I had to replace mine as I too rounded off the internal HEX. Miss-read the torque setting slightly 
Just had a look and this was the description from my sales invoice.
11 * 1 (single) M8 X 40 SKT CAPSC LOW HD G10.9 SELF COLOUR
Unfortunately it looks like the place I got them from (fastfixdirect.co.uk) doesn’t stock them anymore.
Just had a look and this was the description from my sales invoice.
11 * 1 (single) M8 X 40 SKT CAPSC LOW HD G10.9 SELF COLOUR
Unfortunately it looks like the place I got them from (fastfixdirect.co.uk) doesn’t stock them anymore.
Well tonight I decided to replace the clutch after making sure everything was in order and I have the (supposed) correct low profile head bolts (new) which are as per the originals (not especially high tensile).
I have two draper torque wrenches, one 1/2 inch, the other smaller, so after cruising the net for the appropriate torque, which seems to be around 52 ft/lbs or 70 NM, I set about the first and second passes of gradual tightening - 10nm, 25, then 40 - but at this point I was getting misgivings about the strength of the bolts as well as if the wrench itself was accurate, because I was feeling that feeling which you get when a bolt has gone beyond what it can stand ie not getting harder to turn - very unnerving...so stopped and decided to try the bigger wrench -
problem is that the smaller one is in NMs and the bigger in ft lbs - why oh why they can't have both on each I don't know!
Anyhow, backed off the bolts and retorqued to 25ft lb to start - then 40...and got the same horrible feeling with the bolts..and.....snap!!!
No not the bolt, but the damn allen socket split leaving 1/2 of allen key in the bolt head!
I began to also realise that because of the torque I was using the bolt inner hex was starting to slightly mangle (distort), thus the stuck allen head of the socket which I had to gently persuade with a small hammer and punch to loosen its grip-of-death from within the socket! Bit like trying to part two copulating lovers welded together.... with a spoon!
SO -
1. are these 'internet retrieved' figures the real torque settings for these clutch plate bolts? Seem high for the bolts used?
2. are the bolts man enough for the job bearing in mind I had to drill one of them out originally (they seem the same as used before) - they seem far too soft to me!
3. even though I always make sure my 10 year old torque wrenches are alway backed off (unwound) when not in use, should I ditch them both and get new? How can I be sure they are accurate?
cheers from a fed up Keith.... now where is that beer! ...and whiskey..and...
I have two draper torque wrenches, one 1/2 inch, the other smaller, so after cruising the net for the appropriate torque, which seems to be around 52 ft/lbs or 70 NM, I set about the first and second passes of gradual tightening - 10nm, 25, then 40 - but at this point I was getting misgivings about the strength of the bolts as well as if the wrench itself was accurate, because I was feeling that feeling which you get when a bolt has gone beyond what it can stand ie not getting harder to turn - very unnerving...so stopped and decided to try the bigger wrench -
problem is that the smaller one is in NMs and the bigger in ft lbs - why oh why they can't have both on each I don't know!
Anyhow, backed off the bolts and retorqued to 25ft lb to start - then 40...and got the same horrible feeling with the bolts..and.....snap!!!
No not the bolt, but the damn allen socket split leaving 1/2 of allen key in the bolt head!
I began to also realise that because of the torque I was using the bolt inner hex was starting to slightly mangle (distort), thus the stuck allen head of the socket which I had to gently persuade with a small hammer and punch to loosen its grip-of-death from within the socket! Bit like trying to part two copulating lovers welded together.... with a spoon!
SO -
1. are these 'internet retrieved' figures the real torque settings for these clutch plate bolts? Seem high for the bolts used?
2. are the bolts man enough for the job bearing in mind I had to drill one of them out originally (they seem the same as used before) - they seem far too soft to me!
3. even though I always make sure my 10 year old torque wrenches are alway backed off (unwound) when not in use, should I ditch them both and get new? How can I be sure they are accurate?
cheers from a fed up Keith.... now where is that beer! ...and whiskey..and...
Edited by 3Dee on Monday 2nd July 20:09
Have a look at this guide:
http://unbrako.com/dnloadengg.htm
I use Unbrako bolts at work and they are the industrial leaders. You won't find stronger bolts. Any decent wholesaler will be able to order them for you. Use 12.9 grade hardened steel bolts. You will find tightening torques in the guide.
Personally I would also use a low strength thread lock to make sure they don't come loose. You can always remove easily with a little heat.
Mart
http://unbrako.com/dnloadengg.htm
I use Unbrako bolts at work and they are the industrial leaders. You won't find stronger bolts. Any decent wholesaler will be able to order them for you. Use 12.9 grade hardened steel bolts. You will find tightening torques in the guide.
Personally I would also use a low strength thread lock to make sure they don't come loose. You can always remove easily with a little heat.
Mart
During yesterdays fiasco, I kept telling myself, no... thats not right...I knew there was something odd about all this.... Thanks guys!
Considering the state of the original bolts (f
ed allen holes which led to me having to drill out) I believe they were way too tight when the whole kaboodle was delivered to me! - this might be the reason I was having such a problem dis-engaging the clutch!
So the 25ft Lbs sounds much more like it!
...and yes - I always use some blue on the bolts!
...Oh and whiskey? only 'celebrity moan' deffo not irish!
Considering the state of the original bolts (f
ed allen holes which led to me having to drill out) I believe they were way too tight when the whole kaboodle was delivered to me! - this might be the reason I was having such a problem dis-engaging the clutch!So the 25ft Lbs sounds much more like it!
...and yes - I always use some blue on the bolts!
...Oh and whiskey? only 'celebrity moan' deffo not irish!
738 driver said:
.....another one of those little gem's..... Whiskey = Irish way.
Whisky = common other spelling.
G luck.
..Stuff how it is spelt old man.... it tastes even better than it sounds - amen to that! Whisky = common other spelling.
G luck.
...maybe I like the Irish way of drinking Scotch? (ie don't stop!)
..so if I say a person is 'Scotch', does that make me a 'Yank'?
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