Fixing bolts - upper & lower arms to subframe

[Blink]

FC112187A - definitely the right ones this time - 3,4,7,8 here.
Don't forget nuts 5,9 too (FX112057) x 4 req.

[Typhoon190]

Originally Posted by Blink

FC112187A - definitely the right ones this time - 3,4,7,8 here.
Don't forget nuts 5,9 too (FX112057) x 4 req.

Yes, got those too.

[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.

Sent from my SM-A600FN using Tapatalk

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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[DMGRS]

Hello all,
My apologies for my late arrival - we've been decanting and posting a large order from SAIC MG and other suppliers that landed with us on Thursday.

When we originally sourced these bolts, the originals weren't available via XPart etc - it was a bit of struggle to find them, however we did eventually find bolts in the correct size.
Unfortunately the original tensile rating wasn't available, and thanks to a family member helping us out with some loading calculations, we worked out that the 8.8 bolts available to us would be more than adequate for the application, with a 'stretch' point many times higher than the 120Nm these bolts are torqued to.

It seems this bolt must have been faulty; over the last day I've been torquing up several of these bolts in a jig made from part of an old upper arm and subframe to well over 300Nm with no stretching or deformity in any of the bolts I tested from the same batch.

While unfortunate, faulty parts do slip through the net - and we've since commissioned a run of our own 10.9 (and stamped thus) bolts to replace these going forward.
It's worthy of note that we've chosen to replace these with 10.9 simply because they're now available and that was the part fitted at the factory; we've sold many hundreds (possibly over 1,000) of these with just this one going 'ping'. I had the same set on my own heavily-loaded ZT-T without issue for years.

I hope this helps clear things up - quality always has been and always will be our focus.

[marinabrian]

Originally Posted by DMGRS

Hello all,
My apologies for my late arrival - we've been decanting and posting a large order from SAIC MG and other suppliers that landed with us on Thursday.

When we originally sourced these bolts, the originals weren't available via XPart etc - it was a bit of struggle to find them, however we did eventually find bolts in the correct size.
Unfortunately the original tensile rating wasn't available, and thanks to a family member helping us out with some loading calculations, we worked out that the 8.8 bolts available to us would be more than adequate for the application, with a 'stretch' point many times higher than the 120Nm these bolts are torqued to.

It seems this bolt must have been faulty; over the last day I've been torquing up several of these bolts in a jig made from part of an old upper arm and subframe to well over 300Nm with no stretching or deformity in any of the bolts I tested from the same batch.

While unfortunate, faulty parts do slip through the net - and we've since commissioned a run of our own 10.9 (and stamped thus) bolts to replace these going forward.
It's worthy of note that we've chosen to replace these with 10.9 simply because they're now available and that was the part fitted at the factory; we've sold many hundreds (possibly over 1,000) of these with just this one going 'ping'. I had the same set on my own heavily-loaded ZT-T without issue for years.

I hope this helps clear things up - quality always has been and always will be our focus.

Bravo, however do you understand the difference in the applied clamping load of a bolt tightened to 120 NM with a tensile strength of 8.8 and one of 10.9?

I shall enlighten you to save the bother of asking, the clamping load of the 10.9 bolt is 41% greater than that of an 8.8 bolt of the same mechanical dimensions.

When you tighten a bolt to a specified torque, you are placing that fastener in tension, so when you tighten an 8.8 M12 fastener to 120NM you are well into the yield proportions of that fastener.

The result of this is a much shorter life expectancy of the fastener as it is repeatedly loaded and unloaded.

Now this may seem trivial, well I can assure you it is not

You can take this as a constructive criticism, the original designers specified a 10.9 bolt so the bolt diameter could be reduced to it's minimum to achieve the correct clamping load on the joint, in this case M12, and by substitution with an 8.8 tensile strength bolt, you are reducing the clamping load by 41% given the same torque applied to the fastener.

For the first five years of my working life, I manufactured machinery that was designed for the sole purpose of fastening threaded items safely and accurately, understanding that when you tighten a bolt to 120NM you place the fastener into tension, and this is the important figure, along with the resultant clamping load achieved.



I was responsible for the design of the TMS2000 and the TNT2000 range of systems, both introduced in 1991, the TMS2000 was a calibration rig which 12 years after it's introduction was accurate enough to comply with the requirements of ISO 6789.

TNT2000 was a device for measuring both torque and tension preload in fasteners of different tensile strengths, in a range from 10NM up to 5000NM.

To put things into some perspective, if you utilised a TNT2000, the fastener would exercise a clamping load correctly within =+/-1% of design, as opposed to a correctly calibrated torque wrench of +/- 25%.

Measuring elongation of a fastener is roughly +/- 5% accurate, this is the reason in very large fasteners these are hydraulically stretched, and the nut applied hand tight and the fastener relaxed putting the joint into tension accurately.

What I'm trying to point out here is very simple, an 8.8 tensile strength fastener is not suitable for the intended application, and to do so is likely to end in premature failure.

So without obfuscation have I made that clear enough to understand ?

Forget the waffle about faulty parts etc, Ben tightened a fastener which exceeded it's yield strength, nothing more, nothing less

There has never been a shortage of the correct bolt, FC112187 which is identical to FC112187A.

This is the bolt which secures one of the diff mounting brackets fitted to the Freelander, and to try use the excuse that XPart didn't stock the correct part as an excuse to substitute and supply cheap BZP non flanged, non patchlok bolts with an incorrect shank length and tensile strength, without any understanding of the implications other than profit is at best foolhardy.

Anybody can rock up to their local nut and bolt place and buy themselves a box of bolts, for instance a box of 100 can be found HERE for £35, take a look.......specified for a maximum applied radial torque figure of 89NM

Yes, that really is thirty five pence each inclusive of V.A.T., makes them seem a tempting alternative to £4.80 each for the correct part doesn't it?.........only tempting if you don't think about why that price difference exists

Brian

[mbonwick]

I did start typing out a reply, but Brian has covered everything I was going to say, and more, far more clearly than I ever could.


8.8 is not a suitable replacement for 10.9, simple as. The fact that more haven't snapped simply means that the majority of the batch were some way above the minimum requirements of BS EN ISO 898 to be designated 8.8 - Ben obviously just got one that only just made it.



I'm also puzzled why 8.8s were selected at all - I can just about believe that FC112187 was out of stock, but I can't believe that M12x90 10.9 couldn't have been obtained from a fastener supplier - and for a fraction of the ridiculous £4-odd Rimmers currently charge.

[DMGRS]

Hello all,
Thanks for the detailed explanation - we did discuss this all at length; I can't remember the reason why, but FC112187 simply wasn't available to us - and we couldn't source a 10.9 tensile rating bolt at the time.
Cost isn't a factor - at the end of the day, we'd simple charge more if we needed to cover the cost of a more highly-rated fastener.

The calculations I was shown at the time from someone who worked in this field indicated 8.8 would have been sufficient, and as such this is what was selected as our fixing of choice.

I completely accept your superior knowledge in the field, and all bolts supplied going forward will be 10.9 with the correct thread-lock patch.
For now, cost will remain the same (£2.79, or £6.20 for a fitting kit including 2 bolts and a nut) but we may need to review this in due course.

[Blink]

Originally Posted by mbonwick

.... I can't believe that M12x90 10.9 couldn't have been obtained from a fastener supplier - and for a fraction of the ridiculous £4-odd Rimmers currently charge.

Talking of ridiculous: I'm in the process of compiling a nuts & bolts list for the front end refurb and Rimmers price is £75.90 (inc vat, ex delivery). That's for 14 nuts and 20 bolts** - and the list isn't even finished yet! The equivalent list for the rear end refurb came to way over £100. No wonder people scrap these cars.

** Includes the nuts & bolts for these and nothing else: dampers; ARB & lower arms; hubs; calipers; subframe.

[Typhoon190]

Originally Posted by Blink

Talking of ridiculous: I'm in the process of compiling a nuts & bolts list for the front end refurb and Rimmers price is £75.90 (inc vat, ex delivery). That's for 14 nuts and 20 bolts** - and the list isn't even finished yet! The equivalent list for the rear end refurb came to way over £100. No wonder people scrap these cars.

** Includes the nuts & bolts for these and nothing else: dampers; ARB & lower arms; hubs; calipers; subframe.

I agree, it is a large bill. Having said that, every 20 years or so isn't so bad and I would prefer to pay a bit more for good quality parts rather than struggle with a job like I have on this occasion.

All done now though. Quite relieved.

[Typhoon190]

Does anyone have a source for the rear sub frame captive nut KYH100330 please?

Not available from Rimmer Bros at present. https://rimmerbros.com/Item--i-KYH100330

Thanks in advance.

Ben.