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How Tight Should Tower Bolts Be?


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#1 mini670

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Posted 18 January 2012 - 10:24 AM

got the front subframe in, but I'm unsure how tight the large tower bolts should be.
the minispares half oily, half solid kit is fitted. the bolts don't come to a stop they just keep going. this results in the lower poly getting really really compressed down.
also the same question for the tie rods, how can you tell when to stop?

#2 minidave1991-89

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Posted 18 January 2012 - 10:30 AM

Need to get the correct torque settings on the nuts etc.
Tie bar to subframe should be 30NM/22lbf and tie bar to suspension arm 26NM/19lbf.
Doesnt have a torque setting for tower bolt but it should stop at a certain point.

#3 Guess-Works.com

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Posted 18 January 2012 - 10:34 AM

50 lbft tower bolt, 22lbft tie rod nut (through subframe)

#4 tiger99

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Posted 18 January 2012 - 10:39 AM

For a start, it is dangerous to use half poly and half solid mounts, as you will fairly quickly get fatigue cracking in the shell, because the suspension loads will be distributed wrongly. It is far better to use all solid, which improves the handling.

Also, if the tower bolts do not stop when tightened, are they the correct bolts? The threaded end should be much smaller than the main part of the bolt, and they tighten till the shoulder contacts the subframe.

The correct torque is 67Nm for the tower bolts, and 25Nm for all others.

#5 mini670

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Posted 18 January 2012 - 11:11 AM

cheers!
yea is read about the problems fitting solid tops and leaving bottoms rubber. this kit is like a hybrid I guess, solid/poly tower mounts.
have I made a bad decission getting them.
www.minispares.com/Product.aspx?ty=pb&pid=38634&title=

yea the bolts do have a shoulder, and I also though the shoulder should butt up to the subframe.
I'm quite annoyed as this kit cost £18 and may not be any good.

will try to upload a photo, but I'm on mobile at minute.

#6 mini670

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Posted 18 January 2012 - 11:24 AM

photo taken yesterday
http://i98.photobuck...zE0NzcuanBn.jpg

#7 tiger99

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Posted 18 January 2012 - 11:26 AM

What Minispares have sold you is rather pointless, a metal spacer between subframe and shell and a poly bit on top. If you have metal to metal contact at the bottom, what good is the poly? And, if the poly did allow vertical movement you would get rapid wear between the metal spacer and the hole in the crossmember. I would ask for a refund and get a proper solid mount kit elsewhere.

#8 tiger99

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Posted 18 January 2012 - 11:30 AM

Correction, I read the Minispares site wrongly, the poly pad is at the bottom. But if, as claimed, the metal bush at the top stops sideways movement, it is putting a large bending load on the bolt. It is a substantial bolt, and is in no danger of breaking, but it will put an enormous fatigue load into the threaded part of the subframe. The design is just plain wrong.

#9 Guess-Works.com

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Posted 18 January 2012 - 12:03 PM

Avoiding the argument on whether the use of solid & poly is right or wrong...

For the bottom poly mount to be squeezed as much as shown in the photo, does suggest the turret bolt is too high off the cross member, this could be due to incorrect fitting of the solid mount, a discrepancy in the thickness of the mount vs the original or the supporting tube in the cross member has collapsed and you're essentially squashing not only the mount but also the cross member.

Edited by Guess-Works.com, 18 January 2012 - 12:05 PM.


#10 mini670

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Posted 18 January 2012 - 12:36 PM

cheers.
the crossmemebr looked to be in good shape, but ill double check layer on.

could perhaps make a spacer to fit over the threaded part, effectively lowering the shoulder that is supposed to butt up to the subframe? this might stop the huge deformation of the poly bush

#11 mini670

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Posted 18 January 2012 - 12:38 PM

or pocket the alloy top mounts out, lowering the head of the bolt into them. have access to cnc mills at work.

#12 tiger99

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Posted 18 January 2012 - 02:46 PM

If you have access to CNC mills, why not make yourself a full set of really nice solid mounts? The rear mounts are not a CNC job, unless you want to do something really fancy, but can be made from the steel plates removed from old rubber mounts (they usually come adrift anyway) and a bit of extra metal, but the teardrops at the front are most easily machined from solid.

#13 Dan

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Posted 18 January 2012 - 09:13 PM

Fix the problem, not the symptom. Making up spacers and milling parts to take up slack that shouldn't be there is bodgery.

#14 mini670

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Posted 19 January 2012 - 12:58 PM

checked the cross memeber last night, all is well.
think that the alloy tops are twice as thick as they should be, as I fitted the original rubbers and the bolt nipped up nice onto the shoulder.
regarding the solid monuts, from what I read on here they are noisy but vastly improve handling, and a couple of people swapped back to standard.
its quite hard to get a free space on machines, but quick little jobs can be slipped in

#15 xrocketengineer

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Posted 19 January 2012 - 03:17 PM

That is strange. I used that same kit from Minispares and I had no problems during the installation. Everything was nice and snug afterwards. The original rubber bushings were so bad that as I tried to loosen the bolts with the ratchet wrench and long socket extension the bolts would flex and the head would move sideways a significant amount. During installation with the new kit everything remained centered with no movement while torqueing.
I do feel a little more vibration during fast idling when cold. I still need to replace the engine mounts.
Ivan

Edited by xrocketengineer, 19 January 2012 - 03:19 PM.





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