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Topic: Torques... (Read 570 times) previous topic - next topic

Torques...

Not going to get into the whys and wherefores, looks like a very touchy subject for some and not a debate I want to get into!

Spent the best part of yesterday morning removing the lower bolt / nut that secures one of the rear shocks to the beam.

Checked and double checked and it's listed as 70Nm which seemed a lot when some other as equally important fastenings are quoted as less... should have listened to my gut feeling as I stripped the thread to both the nut and the bolt.

Can someone confirm the 70Nm for me, I'm starting to doubt myself.

Another possibility is the bolt, which was sold as a genuine VW one maybe wasn't. Certainly looks genuine but the way it stripped the thread so easily has me doubting that too.

Had to drill progessively larger holes into the nut at 3 o'clock and 9 o'clock to split it in half - have nigh on identical spec. bolts coming from Westfield Fastners, guaranteed quality and about a tenth of the price.

Re: Torques...

Reply #1
70 Nm confirmed but I have a feeling your rear axle is different to the one on my car.  I'll take a look after lunch.

Re: Torques...

Reply #2
Your rear axle is indeed different to mine but the fixing for the rear shocker is the same so I would say the correct torque is 70Nm.  I've also checked, the recommended torque for a M10 10.9 grade bolt is 77Nm.  It should take it if the bolt and nut are the correct grade.
I bought 4 new bolts, 2 for the Golf and 2 for my A2.  The torque specified for the A2 is just 55Nm.  The bolt appears massively over specified for the A2 so that doesn't help. 
I'll probably test the bolt to 70Nm on a bench before fitting to the car.  I still have the captive nuts and don't want to wreck them.

Re: Torques...

Reply #3
That's spot on, thanks... so I wasn't having a moment after all.

The Westfield bolts turned up mid morning after my original post, they were only ordered last night too.

I usually torque up items like this in stages, from the point they begin to bite then even increments to the final value.

The 'genuine' bolt gave up around 50Nm, while Westfields took the 70Nm no problem.

Westfields are the same 10.9 M10x75 1.5 pitch as the recommended VW's but a lesser thread length at 26mm against 45mm.

If you see the point on the VW bolt where the damage occurred that's the farthest up the its shaft the nut is required to go, so more than enough to spare.

Infact it's odd VW spec. 45mm, surely the unnecessary thread would risk damaging the 'eye' of the shock bottom more than if it were unthreaded?

Looks like I've either had an isolated defective bolt or there's something more dodgy about them... wouldn't want it to be either but if it's the latter it's a bad job that you can't rely on safety critical items being what they purport to be.


Re: Torques...

Reply #4
That's a bad failure, looks more like an 8.8 grade bolt.

There is something not great about VW fasteners.  This is a MK2 front sub-frame bolt.  It is supposed to take 130 Nm but I felt it yield before the torque wrench clicked.


Re: Torques...

Reply #5
Wish I hadn't seen that post!

Was doing up the same bolts today and after my strut episode and your one above it was heart in mouth stuff.

When your lying upside down and edging towards 115 Nm it's a bit of an effort... even had to stop and check for unintentional leakage, good job I'd my old troos on.

It's surprising just how little movement it takes to get that last 15Nm.

Without checking, I'm nearly sure it was Febi bolts I was using, it was a set with possibly the subframe and some of the wishbone ones as a pack?

If so, sensible price and no problems with them.   

Re: Torques...

Reply #6
I've been checking the big ends and one of the main crank bearings on the Caddy due to low oil pressure only to find someone has had the crank ground and oversize bearings fitted recently. The torque settings are 30Nm + 90deg and 65Nm +90deg respectively using new VW bolts but I still had an uneasy feeling. Like you I've never done this before but I can't "justify" paying someone to do it when the fix costs are over my budget (read I'm being tight). Sump goes on tomorrow followed by new oil, manual prime to ensure oil is in the system and the clenched buttock start-up!
1991 Tornado Red BB 8v GTI Moredoor
2008 Skoda Octy Scout aka dirty diesel

Re: Torques...

Reply #7
How'd you get on?

Re: Torques...

Reply #8
All back together minus 2x PITA bolts which you can't put in straight and kept falling into the lower bellhousing. Haynes suggests you can install the 23 bolts in 5mins....NOT!
Started-up fine but as expected still low oil pressure but at least it is no worse.
I have a contact who has suggested he verify the pressure with a "proper" gauge, but I'm not sure it will be sufficiently better.
Another job I can say I've done, not sure I'd do it again tho!
1991 Tornado Red BB 8v GTI Moredoor
2008 Skoda Octy Scout aka dirty diesel