Fastest way to settle suspension after car has been lifted
#1
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We worked on the car last Saturday and lifted it in the process. I thought I'd have plenty of time to drive it and made an alignment appointment at dEVEK for Thursday.
Things got hectic, and I only got to drive 15 miles so far. Tonight I did some hard braking and cornering, as well as some speed bumps (slow), but am not convinced that's nearly enough. I will also have about 12 miles to get to DEVEK., which would be 27 miles total.
I feel I need to do something else to settle the suspension - something that doesn't take too much time. What would you do?
Things got hectic, and I only got to drive 15 miles so far. Tonight I did some hard braking and cornering, as well as some speed bumps (slow), but am not convinced that's nearly enough. I will also have about 12 miles to get to DEVEK., which would be 27 miles total.
I feel I need to do something else to settle the suspension - something that doesn't take too much time. What would you do?
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Originally Posted by danglerb
Do you have any fat friends that want a ride?
I have gained a few pounds over the winter - does that qualify?
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Actually, this may be a dumb question, but why does it take so long for the suspension to settle? And why don't other cars have that same problem?
#7
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Nicole:
I lift the front of my car every time I change tires for an autocross. It's probably about 20 miles from my house to our autocross site & that seems to be about right to bring the front end back down. Of course, I do as much check braking - almost to the point of lock up - as I can in those 20 miles.
An easy way to check is to see how many fingers you can fit between the top of your tire and the fender lip before you lift the car - when you get back down to the same number of fingers, the car has settled and you've driven far enough.
As to why it takes so long for the 928 suspension to return to it's static ride height - I've never heard a definative explanation, but I suppose it is a combination of the stiction of the huge (747 sized) bushings in the front end and the inherent lift of the gas shocks.
James
I lift the front of my car every time I change tires for an autocross. It's probably about 20 miles from my house to our autocross site & that seems to be about right to bring the front end back down. Of course, I do as much check braking - almost to the point of lock up - as I can in those 20 miles.
An easy way to check is to see how many fingers you can fit between the top of your tire and the fender lip before you lift the car - when you get back down to the same number of fingers, the car has settled and you've driven far enough.
As to why it takes so long for the 928 suspension to return to it's static ride height - I've never heard a definative explanation, but I suppose it is a combination of the stiction of the huge (747 sized) bushings in the front end and the inherent lift of the gas shocks.
James
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#9
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Most of it is due to the big rear bushing on the lower A-arms. The bolts on the bracket around it can be loosened, if you can get under there with a 19mm wrench, but it needs to be retorqued to 88 ft lbs.
Nicole, there is a good section of uneven pavement, some old railroad tracks, as I recall, south of you on Cedar. Go down there and bomb over the tracks a bunch of times. Do a lot of hard braking (you need to further bed your new pads anyway), anything to get some movement into the suspension.
Nicole, there is a good section of uneven pavement, some old railroad tracks, as I recall, south of you on Cedar. Go down there and bomb over the tracks a bunch of times. Do a lot of hard braking (you need to further bed your new pads anyway), anything to get some movement into the suspension.
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The retained height of the front end after lift is entirely due to the two lower control arm bushings .... at least they are the root cause. Obviously, the unsprung weight is sufficient to cause the wheel assembly to drop when the car is lifted; however, when the car is lowered, more torque must be applied to the LCR that the ample static mass of the car provides. The bushings are acting like a one way clutch, and the same behaviour would be observed if the shock were dead or absent.
The WSM's provide the "pull-down" method with a bar and chain fall prior to alignment .... or as most do - drive 'X' miles. The magnitude of 'X' is becoming Urban Legend: the true test is to measure the suspension height points .... and the restored fender height is adequate for this ( provided the previous value was recorded
). Some cars take very little driving/speed bumps/braking to return to 'normal'
Having waffled through all that, the quick and dirty method I have used is to back off the torque on the four bolts for each LCR before lowering the car, and let it sit overnight - or take a slow drive around the block: then reach under with a torque wrench and tighten everything to spec .... the correct height has been restored. This releases the pressure on the 'one way clutch' effect of the bushings.
The WSM's provide the "pull-down" method with a bar and chain fall prior to alignment .... or as most do - drive 'X' miles. The magnitude of 'X' is becoming Urban Legend: the true test is to measure the suspension height points .... and the restored fender height is adequate for this ( provided the previous value was recorded
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Having waffled through all that, the quick and dirty method I have used is to back off the torque on the four bolts for each LCR before lowering the car, and let it sit overnight - or take a slow drive around the block: then reach under with a torque wrench and tighten everything to spec .... the correct height has been restored. This releases the pressure on the 'one way clutch' effect of the bushings.
#12
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hey nicole, you have to thrash the car when you drive it to really get it to settle - as others have mentioned with hard braking till the abs cuts in and the car stands on its nose and really piling it into corners.. otherwise it takes a longer distance with regular driving.
#13
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I do hard braking and I usually throw the car from side to side as I go down the neighborhood streets. I once had a neighbor ask me, "What thell are you doing?" ![Roll Eyes (Sarcastic)](https://rennlist.com/forums/images/smilies/rolleyes.gif)
That seems to get me 80-90% there. The potholes in Michigan do the rest.
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That seems to get me 80-90% there. The potholes in Michigan do the rest.
#14
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Same here - I just drive around the neighborhood of over to the market and that normally settles things down. But the front seems to take the longest to return to normal.
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There is a 4 mile stretch of "corrugated & small pothole macadam" rural road about a mile from my house. I drive up and down that road at about 40 mph once (normal speed is ~25 mph!). When I return to the house, the car is settled. The more suspension action you can get, the faster the car will settle back to the stable ride height. Good Luck!!
Gary Knox
West Chester, PA
Gary Knox
West Chester, PA