Fixing bolts - upper & lower arms to subframe

[Blink]

I was just making sure the 4 bolts line up with the 4 captive nuts when I realised the shanks stop well short of the start of the nuts. This means that some of the bolt thread is inside the bushes on the arms (instead of the shank reaching the whole length of the bush). Is this normal? - it doesn't seem right to me.




Two more questions.

Is there any reason not to stick a washer under each bolt head to stop it from ripping the paint to bits and causing rust to start?

What are those two threaded holes in the flat black crossbar thingy between the bolts? (arrowed here).

[breakfastinsmethwick]

The threads are not a problem as long as the bolts protrude out of the other side of the captive nuts. However are the bolts the correct property grade? They also are not dacromate as were the originals, so may be more subject to corrosion and long term, stress corrosion failure. Me being me would get the correct bolts if still available.

I would not use any washer that was not hardened on safety critical components otherwise it may lead to loss of bolt tension. Another reason to buy the originals.

All just my experience having worked in durability testing. Others will have different opinions.

[Blink]

Originally Posted by breakfastinsmethwick

The threads are not a problem as long as the bolts protrude out of the other side of the captive nuts. However are the bolts the correct property grade? They also are not dacromate as were the originals, so may be more subject to corrosion and long term, stress corrosion failure. Me being me would get the correct bolts if still available.

I would not use any washer that was not hardened on safety critical components otherwise it may lead to loss of bolt tension. Another reason to buy the originals.

The bolts do protrude out of the captive nuts (just).

I don't know if the bolts are the correct property grade - I assume they are because they're the fixing kits that came with the upper & lower arms, all supplied by DMGRS (see dropdown box here).

The bolts supplied by Rimmers (4,3,8,7 here) appear to have the same length shank but a different coating, which might or might not be Dacromet?

I just checked and the shank on the DMGRS bolts is 8mm shorter than the metal tube in the bush - i.e. there's 8mm of thread inside the metal tube. If I'd designed this the shank and the metal tube would be exactly the same length.

[Blink]

PS. The DMGRS bolts have the marks TY 8.8 and KEF 8.8 on them (4 of each) (some of the nuts have grip grooves, the others don't)

I don't know about the Rimmers bolts because I've never seen one. They're definitely a different coating though. Ditto for the Rimmers nuts on the same page. DMGRS's bolts & nuts all have a much brighter finish.

[KWIL]

The correct bolts have flanged heads and do not need washers. The 4 nuts used also should be flanged.

[The Mighty Quinn]

As above, get the correct items from Rimmers - flanged head with Dacromet finish. No point getting aftermarket items when you're going to the trouble.

Cheers,
Karl.

[clf]

Originally Posted by Blink

Yes, I'll stick to the original MGR ones but the £££s are getting really silly now. The 10.9 arm bolts & nuts are £34.16. Then there's another £50.40 on sill trim clips (post 15). That's £84.56 plus (say) £10 postage = £94.56. Add the £13.40 I already spent on the 8.8 bolts & nuts and it's nearly £108 just for a few fixings. Ridiculous.

I feel your pain. £72 a couple of years ago for the nuts and bolts for the rear suspension, incl the 4 for the subframe. I did find them slightly cheaper elsewhere by only about 4 pounds though. But as I was getting a fuel tank strap from rimmers anyway, it settled my mind knowing they were the correct ones getting them from rimmers.

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[alanaslan]

Originally Posted by clf

I feel your pain. £72 a couple of years ago for the nuts and bolts for the rear suspension, incl the 4 for the subframe. I did find them slightly cheaper elsewhere by only about 4 pounds though. But as I was getting a fuel tank strap from rimmers anyway, it settled my mind knowing they were the correct ones getting them from rimmers.

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It is so sad to see bolts selling at these prices. We used to have a company locally nuts and bolts were their game. You could get anything you wanted for pence not pounds, sadly Robert retired around the same time as I did 2010 and nobody took over the business. He was great he supplied the aerospace industry, to the ship builders on the Clyde and most of the UK. He had 5 staff but with him passing away just after he retired all his knowledge was lost forever.
Alan


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[alanaslan]

The bolts that are required to attach the upper and lower arms on the rear sub frame are the same both for the top and the bottom. The bolts required are what are called Flanged head bolts they are 90mm long and have a diameter of 12mm. PLEASE NOTE THESE BOLTS NEED TO BE HIGH TENSILE. So that is a total of 8 M12 90mm high tensile flanged bolts. I normally would fit flanged nuts and assemble with blue Locktight thread seal. Due to a recent Amendment sent to MOT testing stations I have to suggest that you use a flanged nylock nut I would still however use thread seal when assembling. Don't worry if there is still some thread inside the fully assembled part this is normal.

[Ducati750cc]

Originally Posted by alanaslan

The bolts that are required to attach the upper and lower arms on the rear sub frame are the same both for the top and the bottom. The bolts required are what are called Flanged head bolts they are 90mm long and have a diameter of 12mm. PLEASE NOTE THESE BOLTS NEED TO BE HIGH TENSILE. So that is a total of 8 M12 90mm high tensile flanged bolts. I normally would fit flanged nuts and assemble with blue Locktight thread seal. Due to a recent Amendment sent to MOT testing stations I have to suggest that you use a flanged nylock nut I would still however use thread seal when assembling. Don't worry if there is still some thread inside the fully assembled part this is normal.

If you look at the photo's on post 30 you will see that to get a nut to sit flush, as it should, with the subframe face, the old flange nut cages would have to be dressed off, simple for the lower arms, not so for the upper arms.