jeffw
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| posted on 28/6/09 at 06:41 AM |
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Live Axle question
On my Phoenix I have a English Axle, panhard rod trailing arm set (standard stuff for a Sylva or 7 I assume).
The touble is that with nobody in the the car it sits down on the rear drivers side by about 15mm. This is with the shock seat on the drivers side up
as far as it will go and the seat on the passenger down as far as it will go. With the shocks seats level each side it's more like 40mm
difference in ride height at the rear.
This situation started when the car went into a well know kitcar garage some 2 years ago because the diff needed new bearings. The car was meant to
be corner weighted as well afterwards and when the car came back it was sitting down on the drivers side with no one in it (obviously further down
with just me in it).
I've tried to cure the issue by move the shock seats but this isn't working.
I'm assuming that the rear axle was removed to do the bearings so there must be something about the way it was re-assembled ....Anyone one have
any ideas what could cause this ?
I have tried slackening off the panhard rod and made sure the trailing arms arn't binding.
[Edited on 28/6/09 by jeffw]
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mookaloid
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| posted on 28/6/09 at 06:58 AM |
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you need to go around and underneath with a tape measure and find out where the problem is. something isn't right. is the axle sitting parallel
with the chassis? is something bent underneath? what happens if you swap the shocks from side top side?
Are you measuring wheel to the wheelarch? is the body on square? has it been repaired badly? are they all like that?
just a few questions I would be asking 
"That thing you're thinking - it wont be that."
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StevieB
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| posted on 28/6/09 at 07:22 AM |
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When setting the ride height of the car, you should work diagonally, so os rear and ns front together, then the opposite corners and then tweek until
correct.
It may be (and sounds likely) that something else is causing a problem, but it's quick and free to adjust the ride height ll round to try and
solve the problem.
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jeffw
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| posted on 28/6/09 at 07:49 AM |
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The ride heights have been set since this has happened by Mark Fisher and he can't get them level at the back. The car was fine prior to the
diff issue so it isn't a bad accident repair issue.
I don't think anything it bent but I will check.
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Peteff
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| posted on 28/6/09 at 08:40 AM |
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Did you measure it before it was worked on ? Is it same with the dampers swapped over, I can't see how anything they did when reassembling could
have caused this problem unless they actually swapped your parts for some different ones. If your springs are sagging it is nothing to do with any
assembly work you need new springs or a different length and rating.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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short track 123
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| posted on 28/6/09 at 10:40 AM |
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If all they have done is to replace the diff bearings there should be no need to remove the axle.
Did they give you a print out from the corner weights before and after if any adjustment was done ?
Jason
Shorttrack MotorSport Ltd
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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jeffw
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| posted on 28/6/09 at 02:04 PM |
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There was no print outs. The car was 'visual' flat on the back before the corner weighting/diff work and now it sits down on the drivers
side regardless of what you do.
I should point out that the diff work was due to a destroyed bearing so I'm fairly certain the axle was dropped to check everything (crownwheel
etc).
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StevieB
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| posted on 28/6/09 at 09:49 PM |
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Have you checked all mounting points etc. to make sure no brackets have snapped or bent.
But of a stumper this one!
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procomp
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| posted on 29/6/09 at 07:07 AM |
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Hi
What are the spring poundage's front and rear. Front spring platforms may be set way out IE front left too high holding the back right down.
Also have you slackened all the bolts on the trailing arms. Assuming you have the metalastic bushes fitted if they are tightened whilst not at ride
height it is possible for them to hold the chassis in a position that is not natural. Just try slackening them of and re tighten at ride height or
after corner weighting.
Think it was already mentioned but have you checked that all the trailing arm brackets are fully attached to both the axle casing and the chassis. It
is not uncommon for the brackets to become detached at the chassis due to the desighn of the trailing arm setup causing stress on the brackets.
Usually the rear ones go first on the chassis.
Cheers Matt
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jeffw
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| posted on 29/6/09 at 08:13 AM |
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Thanks for all the suggestions.
The springs haven't been changed so it is unlikely that this would cause this effect. The front shock seats are identical to each other and
produce equal ride heights.
I will check the rear arms as this would seem to be the most likely area. Do I need to slacken the arms off with the weight off the axle and then
lower it so it adjusts itself and then tighten up again ?
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procomp
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| posted on 29/6/09 at 08:20 AM |
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Hi
Just slacken the bolts and then re tighten at natural ride height when on it's wheels. Or alternatively jack car up and remove rear wheels and
place a pair of small axle stands under the axle to replicate a loaded state and re tighten the bolts. In theory if this is the problem just
slackening the bolts will allow the car to sit more naturally with just the bolts slackened. Obviously re tighten as above anyhow as it's best
practice with metalastic bushes.
Cheers Matt
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MikeRJ
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| posted on 29/6/09 at 11:12 AM |
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quote:
Originally posted by jeffw
The springs haven't been changed so it is unlikely that this would cause this effect. The front shock seats are identical to each other and
produce equal ride heights.
Were are you measuring ride height to? If you are measuring from ground to the body, perhaps the body has not been fitted very squarely to the
chassis?
If you are measuring from the ground to to the chassis and the car is sat on a completely level surface with all tyres correctly inflated, then the
only way you could have equal ride heights at the front but not at the rear is if you have a twisted chassis!
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jeffw
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| posted on 29/6/09 at 11:41 AM |
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Sorry Guys obviously not making myself clear.
Car was fine prior to diff repair & corner weighting by well known kit car company (who shall not be named as this was 2 years ago and I
didn't allowed them the oppurtunity to resolve the issue.)
No body repairs or shock/spring changes have taken place. Front shocks have the same settings side to side and the front ride height to the body is
fine.
The issue appears to be at the rear of the car only.
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