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.

[marinabrian]

8.8 throw them in the bin and buy the proper items

BOLT for eight


STIFFNUT for four

And only apply coppaslip sparingly to the plain shank part of the bolt, and NOT the threaded section, as these are patchloc and more importantly are 10.9 tensile strength

I cannot believe DMGRS supplied standard M12 bolts, non flanged and of incorrect tensile strength, put into context the maximum torque that can be applied to an 8.8 M12 bolt is 70Nm...........so how does that compute with a bolt that is specified to be tightened to 120Nm.

I will let that sink in for a minute before the horror of what I've just said crystallises in your mind, absolutely disgraceful disregard for safety

Brian

[Blink]

I bought the arms from these two links. The fitting kits I got (with unflanged bolts) are from the dropdowns:
https://www.dmgrs.co.uk/products/r75...-and-rgg104972
https://www.dmgrs.co.uk/collections/...nuine-mg-rover

The bolt kits on this page are also unflanged - https://www.dmgrs.co.uk/collections/...olts-fc112187a
The nut kits on this page are flanged - https://www.dmgrs.co.uk/collections/...tainless-steel

Now, there's a single page with all the arm items bundled together and the pic shows flanged bolts & flanged nuts which appear to have the same colour/finish as the ones on Rimmers. https://www.dmgrs.co.uk/collections/...2057-xpbundle2

I didn't know M12 bolts marked '8.8' are only specified to 70Nm, so I'll replace them (and the nuts) with these Rimmers items:
https://rimmerbros.com/Item--i-FC112187A
https://rimmerbros.com/Item--i-FX112057
Oh no, more money (£34.16).

[Blink]

These are the arm nuts I got. The two on the left are one pair, the two on the right are another. One pair has a grooved flange, the other is a locknut.

[Spike]

Originally Posted by marinabrian

8.8 throw them in the bin and buy the proper items

I cannot believe DMGRS supplied standard M12 bolts, non flanged and of incorrect tensile strength, put into context the maximum torque that can be applied to an 8.8 M12 bolt is 70Nm...........so how does that compute with a bolt that is specified to be tightened to 120Nm.

I will let that sink in for a minute before the horror of what I've just said crystallises in your mind, absolutely disgraceful disregard for safety

Brian