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Bolting up the suspension...
bigandy - 1/3/07 at 01:00 PM

afternoon folks,

I am just starting to prepare my car to be taken off the build stands, and put on the floor, so I can shift it out of the garage and prep the engine. Anyway, I was just wondering what peoples thoughts were on bolting up the suspension arms/dampers etc.

They are all fitted with metalastic bushes, and so far they are all in place with the bolts fitted and the nyloc nuts done up hand tight (i.e not very!). I'm sure I have read somewhere that it is best to let the car support it's own weight before tightening any suspension arms etc etc.

I'm going to have a problem with that in some places though, where the bolts/nuts will be very difficult to get access to when the wheels are on. So, can anyone see any problems with torqueing up the bolts that are going to be awkward to tighten before dropping the car onto its wheels, then torquing up the rest...

Cheers
Andy

Mr Whippy - 1/3/07 at 01:22 PM

you will damage metalastic bushes that way. They must be at normal ride position before tightening.

bigandy - 1/3/07 at 01:29 PM

Ah, this is going to be an arse of a job I think then, because it is going to be virtually impossible to get at the bolts when the car is on the ground....

I don't suppose you could tell me how the bushes will be damaged?

Cheers
Andy

westf27 - 1/3/07 at 01:37 PM

support the car on axle stands with the wheels off then tighten bushes

Mr Whippy - 1/3/07 at 01:38 PM

I had better rephrase that; they will be damaged if you do not tighten them up with the suspension at normal ride high. Or else the rubber will be stressed and that is what causes failure.

Simply tighten up with the suspension arms horizontal.

[Edited on 1/3/07 by Mr Whippy]

greggors84 - 1/3/07 at 02:29 PM

If you were using poly bushes you shouldnt have this problem as the crush tubes should take the clamping force of the bracket.

designer - 1/3/07 at 03:03 PM

Keep all suspension bolts loose until everything heavy is fitted. Then bounce chassis up and down and roll a few times, THEN tighten.

The brackets should clamp the inner tube tight.

MikeRJ - 1/3/07 at 04:08 PM

quote:
Originally posted by greggors84
If you were using poly bushes you shouldnt have this problem as the crush tubes should take the clamping force of the bracket.


The clamping force from the bolts is resisted in the same way by a crush tube in metalastic bushes. The reason polybushes don't suffer from this issue is because the polyurethane doesn't have to deform when the suspension moves, i.e. the crush tube can rotate without moving the bush material.

If it's going to be difficult to do up the bolts with the wheels on then either support the weight of the car with axle stands on the hubs or ends of the wishbones, or remove the shocks and tighten the bolts with the wishbones at the appropriate angles.

[Edited on 1/3/07 by MikeRJ]

bigandy - 1/3/07 at 06:06 PM

Cheers for the tips folks. I have removed the dampers and set the wishbones at roughly the right angle for normal ride height before doing up the awkward nuts/bolts. The remaining ones can be got at fairly easily, so I'll do them after the car is on the ground supporting its own weight.

Cheers
Andy