Bolt hole reduction: round shim / sleeve?
Discussion
Quick boring question for someone that has encountered this problem before; I've installed new dampers which have a mounting hole interior diameter slightly larger than the previously installed ones. The OD of the shoulder on the bolt is therefore not quite big enough, causing rattles. Is there a suitable way to shim out the hole, or a source for a sleeve that can go in?
I would have to guess how much discrepancy there is but it can't be much more than a couple of mm. My DIY approach would probably involve chopping up bits of Coke can to pack it out, or drilling out a bit of aluminium rod if I could find something to fit.
I would have to guess how much discrepancy there is but it can't be much more than a couple of mm. My DIY approach would probably involve chopping up bits of Coke can to pack it out, or drilling out a bit of aluminium rod if I could find something to fit.
I have turned a sleeve out of mild steel on a lathe before, I reamed the hole and made the sleeve slightly oversize so it'd be a tight push fit. I wound the sleeve in with an old nut and bolt. It's still working very well a couple of years later. I wouldn't bother attempting it with anything other than a turned piece of steel though, you'd be wasting your time with coke cans.
Thanks for the replies I think they confirm my suspicions. The drinks can shim would be a temporary fix (stop gap?), with luck I should be able to get an aluminium sleeve made to fit.
I'd considered the bigger bolt idea, but it's not so attractive as it would involve modification to the rest of the mounting point.
I'd considered the bigger bolt idea, but it's not so attractive as it would involve modification to the rest of the mounting point.
What application? Generally the bolt at the end of a damper is not a pivot, it should be clamped up tight? Any movement should be on either a rubber bush or a spherical joint, not the bolt.
Edited to say stick to steel, aluminium and steel plus road salt means massive corrosion and either impossible to dismantle or falls to bits of its own accord.
Edited to say stick to steel, aluminium and steel plus road salt means massive corrosion and either impossible to dismantle or falls to bits of its own accord.
Correct, shock eye should be a pivot point but the OP says he has a couple of millimetres of movement and it knocks and bangs, so I'd say its wrong. I'm not even sure I'd drive it in that state.
OP thinking about it are you sure you have the correct bushings ? look at powerflex/superflex etc and see if there is a better fit ? Is this shock meant for the application ? have you talked to the manufacturer at all ?
OP thinking about it are you sure you have the correct bushings ? look at powerflex/superflex etc and see if there is a better fit ? Is this shock meant for the application ? have you talked to the manufacturer at all ?
AdrianR said:
What application? Generally the bolt at the end of a damper is not a pivot, it should be clamped up tight? Any movement should be on either a rubber bush or a spherical joint, not the bolt.
Edited to say stick to steel, aluminium and steel plus road salt means massive corrosion and either impossible to dismantle or falls to bits of its own accord.
It's nothing special, typical damper mount, and in this case the forces are intended to be transmitted via the bolt, it needs to be a good fit. I've also managed to upgrade my quick fix from a bit of aluminium can to some steel pipe. Will get a proper sleeve made in steel in due course, fortunately the car is barely used.Edited to say stick to steel, aluminium and steel plus road salt means massive corrosion and either impossible to dismantle or falls to bits of its own accord.
Edited by TheInternet on Sunday 14th July 20:23
I maintain that no force should ever be transmitted on a loose bolt, so if it rattles it is wrong and will eventually break. A pothole at 60ph puts quite a kick through the mounts before the damper reacts, so please tell me it doesn't locate the suspension and can't jam your wheel or steering if it snaps.
(Sorry, tad patronising there, but you get the idea)
(Sorry, tad patronising there, but you get the idea)
Edited by AdrianR on Sunday 14th July 20:44
AdrianR said:
I maintain that no force should ever be transmitted on a loose bolt, so if it rattles it is wrong and will eventually break. A pothole at 60ph puts quite a kick through the mounts before the damper reacts, so please tell me it doesn't locate the suspension and can't jam your wheel or steering if it snaps.
(Sorry, tad patronising there, but you get the idea)
No need to apologise for trying to keep people safe. The bolt has been tightened to about 90Nm, it's not loose, to describe it as a rattle was perhaps a poor choice. As mentioned above it's unlikely to be used before being resolved.(Sorry, tad patronising there, but you get the idea)
HustleRussell said:
you'd be wasting your time with coke cans.
I have seen coke can shims made for compression strut rose joint bolts on an Escort rally car where the collars on the weld on brackets were drilled slightly too large for the bolt.I can confirm that if done correctly,(one layer only) they are very effective,and being as they are still on the car some 4-5 years later obviously durable and according to the owner they stop the bolts from seizing.
TheInternet said:
No need to apologise for trying to keep people safe. The bolt has been tightened to about 90Nm, it's not loose, to describe it as a rattle was perhaps a poor choice. As mentioned above it's unlikely to be used before being resolved.
Clearly having 2mm of clearance is wrong, but the steel tube in the middle of the bush should be clamped at either end by whatever bracket it's installed in, so even with the excess clearance it shouldn't be moving. There is no situation where the design should rely just on the clearance between the bolt and the bush tube to prevent movement.If there is 2mm clearance then a bush with just under 1mm wall thickness is needed, and it's entirely possible to turn one of these out of steel (not aluminium) on a lathe.
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