22 replies to this topic

[MatthewsDad]

I have replaced the bushes on my front suspension tie bars ('95 Cooper SPI) but when I came to torque the front tie bar to subframe locknut (30Nm according to Haynes) I realised there is no space to fit my torque wrench to the locknut.  In the absence of any special tool, can anyone advise on an appropriate 'rule of thumb' level of tightness for the nut?

 

I have fitted a poly bush on the outer part of the tie bar and a rubber one on the inner part.  As I was tightening the nut both the bushes obviously compressed and spread a little, and I guess there's a point beyond which they won't be doing their job if they're too compressed?  I plan to get the tracking done shortly but in the meantime I just want to be sure things are safe and sound.

 

Many thanks

[Fast Ivan]

the nut should bottom out if I remember right

as far as torque goes, in the absence of using the torque wrench, the correct size spanner will have a length that will enable you to tighten it up without overstressing unless you're hanging off it, but its still guess work really 

one other tip is make sure the car is on its wheels before you nip them up

[nicklouse]

Some ideas drop the car onto its wheels the angle of the tie bar changes you should be able to get the torque wrench on. You should be tightening the bushes up at ride height anyway.

The other is put a nut and bolt in a vice ant tighten to xyz Nm and then feel with the spanner you will be using to tighten the tiebar nut you then have an idea that you will not be over tightening it.

But yes it bottoms out.

[Blatherskite]

30 Nm is a torque of 30 newtons (or 3kg force) applied at a radius of 1 metre. Or, 6kgf at 0.5m, 12kgf at 0.25 metres, and so on.

You can get close by measuring the length of the spanner to where you will be pressing with your hand, and pushing with what you reckon is the right force. Try lifting the right weight with your arm to "calibrate" yourself.

[Nu2mini]

Take all the guess work out of the job and treat yourself to a set of these

 

http://www.ebay.co.uk/itm/131491352400

[Cooperman]

You need to use a Nyloc nut and tighten it until the big washer bottoms-out on the step of the tie-bar. The actual torque is not so critical with a big Nyloc, it's just important that the washer is firmly against the step.

For best security the thing to do is to drill the tie-bar and use a castellated nut with a split pin. Never re-use the Nyloc nut from the tie-bar as it is very 'safety-critical' and Nylocs are supposed to be 'single-use-only' - well, in aviation they certainly are..

[MatthewsDad]

Thanks everyone for your advice.  I used nyloc nuts front and rear and the front one bottomed out with just a couple more turns of the spanner.  (I'll get some crow's feet too)

[Spider]

You need to use a Nyloc nut and tighten it until the big washer bottoms-out on the step of the tie-bar. The actual torque is not so critical with a big Nyloc, it's just important that the washer is firmly against the step.

For best security the thing to do is to drill the tie-bar and use a castellated nut with a split pin. Never re-use the Nyloc nut from the tie-bar as it is very 'safety-critical' and Nylocs are supposed to be 'single-use-only' - well, in aviation they certainly are..

 

I am not sure what the situation is in the UK, but out here in this Colony, fasteners for suspension and steering had to be 'locked' in some way. In the case of the Tie Bars, they were drilled and had a split pin, or later and R clip fitted at the factory, though some of these were fitted with Nylocs too, problem with this being that as the Nylon in the Nyloc runs over the drilled hole, it cut a lovely thread in it!!  so the Nylocs didn't lock, luck for the Pin,,,,

 

These days, I fit a plain nut and then a lock nut.

[Cooperman]

I normally use a Nylok on road cars and a castellated nut with split pin on any competition cars.

I never re-use a Nylok on any critical components.

[Fast Ivan]

I avoid reusing nylocks

I also advise not using them on stainless - I've seen crevice corrosion after time due to the nylon forming a perfect seal and therefore the stainless not getting any oxygen, even the more exotic stainless steels out there are vulnerable

[Spider]

I avoid reusing nylocks

I also advise not using them on stainless - I've seen crevice corrosion after time due to the nylon forming a perfect seal and therefore the stainless not getting any oxygen, even the more exotic stainless steels out there are vulnerable

 

I know I'll likely have rocks thrown at me, but I recon Stainless Steel is a crap metal for just about anything!

[Carlos W]

 

I avoid reusing nylocks

I also advise not using them on stainless - I've seen crevice corrosion after time due to the nylon forming a perfect seal and therefore the stainless not getting any oxygen, even the more exotic stainless steels out there are vulnerable

 

I know I'll likely have rocks thrown at me, but I recon Stainless Steel is a crap metal for just about anything!

 

 

No rocks here. 

[Cooperman]

Stainless steel is fine for knives & forks  .

In fact in high-corrosion, low stress load cases it works well.

I had a car with an alloy block & heads and someone with a similar car was telling me how he had changed the manifold bolts from mild steel to stainless steel. That would have caused an even greater electrolytic action between the dissimilar metals. The real solution to steel bolts into aluminium alloys is to Heli-coil the holes and use MS or HTS bolts. That is what is done on aero-engines to prevent thread strength being lost due to corrosion and repeated tightening and undoing of the bolts. 

If you have a Mini gearbox which comes to pieces fairly often it can be a good idea to Heli-Coil all the threaded holes in the casing.

[Spider]

Stainless steel is fine for knives & forks  .

 

Might be fine for forks but not ideal for knives, you can't keep a good sharp edge on Stainless - it's just crap (almost).

Edited by Moke Spider, 19 May 2015 - 10:17 AM.

[Cooperman]

 

Stainless steel is fine for knives & forks  .

 

Might be fine for forks but not ideal for knives, you can't keep a good sharp edge on Stainless - it's just crap (almost).

 

It's that 'foreign' so-called stainless.

You need good old-fashioned 'SHEFFIELD' stainless steel. Oh, do they still make steel in Sheffield?