Rear ride height adjustment
04-27-2003, 04:53 AM
#1
Three Wheelin'
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Rear ride height adjustment
I recenltly hav been fitting a different set of rims on my 1989 C4. In doing do I found that the right side rear rim is hitting the upper wheel well while the left side is not.
After a 'brief' investigation I noted that
1. I had adjustable rear koni shocks
2. There appears to be a ride height adjustment on the shocks
3. The two sides are (left / right) are definetly set very differently. (Hence the right side sitting lower)
4. I dont have the tool that would set the ride height.
Anybody know what I'm talking about or have any advice to offer??
Kirk
p.s. I am not talking about the shock dampening setting on top of the koni shock.
After a 'brief' investigation I noted that
1. I had adjustable rear koni shocks
2. There appears to be a ride height adjustment on the shocks
3. The two sides are (left / right) are definetly set very differently. (Hence the right side sitting lower)
4. I dont have the tool that would set the ride height.
Anybody know what I'm talking about or have any advice to offer??
Kirk
p.s. I am not talking about the shock dampening setting on top of the koni shock.
04-27-2003, 06:51 AM
#2
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Dear Kirk,
First off all you have to let us know what wheels and tyres you are using. Need all wheel dimensions as well as the offset which is by the air valve. Full tyre dimensions are also required.
To the suspension adjustment, you are talking about the spring perches. However setting levels are often no even from side to side because these are used to level ride height (10 mm adjustment) and are also used to corner balance.
My advice in this case is to have the ride height correctly measured for level and also the corner balance checked. I would also advise you have the rear wheel alignment checked. I certainly do not advise you try and adjust this yourself.
There are a large number of possibilities which can cuase this kind of problem and I recommend you obtain a set of measurements or datum points before you start looking at adjusting things.
For the record I have seen this before a number of times and each time the fault was different.
Please also remember that ride height is set by the compressed length of the front strut and rear shock absorber assemblies. The rear shocks are pre-tensioned. The 89C4, 1990 and some 1991 models (built prior to Nov 1st 1990) are pre-tensioned differently to the later models. The 89C4 needs special rear shocks 8241-1104Sports. The springs must also be the correct length (rear ones) for the 89C4. All this needs to be checked. I have seen many incorrect suspensions installed especially on 89 and 90 models including 996 springs so please check as much as you can.
Ciao,
Adrian
911C4
First off all you have to let us know what wheels and tyres you are using. Need all wheel dimensions as well as the offset which is by the air valve. Full tyre dimensions are also required.
To the suspension adjustment, you are talking about the spring perches. However setting levels are often no even from side to side because these are used to level ride height (10 mm adjustment) and are also used to corner balance.
My advice in this case is to have the ride height correctly measured for level and also the corner balance checked. I would also advise you have the rear wheel alignment checked. I certainly do not advise you try and adjust this yourself.
There are a large number of possibilities which can cuase this kind of problem and I recommend you obtain a set of measurements or datum points before you start looking at adjusting things.
For the record I have seen this before a number of times and each time the fault was different.
Please also remember that ride height is set by the compressed length of the front strut and rear shock absorber assemblies. The rear shocks are pre-tensioned. The 89C4, 1990 and some 1991 models (built prior to Nov 1st 1990) are pre-tensioned differently to the later models. The 89C4 needs special rear shocks 8241-1104Sports. The springs must also be the correct length (rear ones) for the 89C4. All this needs to be checked. I have seen many incorrect suspensions installed especially on 89 and 90 models including 996 springs so please check as much as you can.
Ciao,
Adrian
911C4
04-27-2003, 06:40 PM
#3
Three Wheelin'
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Adrian,
If it was as simple as taking it into a shop that knew what they were doing and had the right tools I would already have done it.
Unforuntely here in Manitoba, every shop I contacted quickly left me with the belief they know even less than I do about this.
As I have only recently purchased this car I am still figuring out from past reciepts, etc what the previous owners had done.
When I bought the car the P.O. mentioned he had the car levelled. This appears to have meant they left about an inch less clearance on the right rear wheel well over the left.
I agree with you on the model of the Konis. I believe they are 8241-1104 sports.
So my first task is to figure out where I can buy the tool to adjust the rear ride height. Then I will look at the procedure to do it.
Any ideas?
Kirk
If it was as simple as taking it into a shop that knew what they were doing and had the right tools I would already have done it.
Unforuntely here in Manitoba, every shop I contacted quickly left me with the belief they know even less than I do about this.
As I have only recently purchased this car I am still figuring out from past reciepts, etc what the previous owners had done.
When I bought the car the P.O. mentioned he had the car levelled. This appears to have meant they left about an inch less clearance on the right rear wheel well over the left.
I agree with you on the model of the Konis. I believe they are 8241-1104 sports.
So my first task is to figure out where I can buy the tool to adjust the rear ride height. Then I will look at the procedure to do it.
Any ideas?
Kirk
04-27-2003, 09:16 PM
#4
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Kirk,
I would be cautious about adjusting the rear ride height without corner balancing all 4 corners - having the corner weights off can produce some odd handling. Have you contacted anyone in the Red River PCA Region, in the Manitoba area, for a contact? Dave Grant at d.g@mts.net is the President, perhaps he could provide a lead.
You can get an adjustment wrench for struts from several sources. I would check with Pegasus Racing (www.pegasusautoracing) or Racer Parts Wholesale (www.racerpartswholesale.com). In terms of corner or weight balancing, you can spend roughly $1000 on Longacre scales, or the Ruggles scales are around $425 (Pegasus has them). There's also a good article by Mike Piera written some years ago about how to corner balance using 4x6's and a household scale. If you scan the archives, you'll find several people, myself included, who have posted their corner weights after balancing. If you need theory on corner weights, that's been discussed in both the racing and 911 Rennlist email lists over the years, or any number of books cover it.
I would be cautious about adjusting the rear ride height without corner balancing all 4 corners - having the corner weights off can produce some odd handling. Have you contacted anyone in the Red River PCA Region, in the Manitoba area, for a contact? Dave Grant at d.g@mts.net is the President, perhaps he could provide a lead.
You can get an adjustment wrench for struts from several sources. I would check with Pegasus Racing (www.pegasusautoracing) or Racer Parts Wholesale (www.racerpartswholesale.com). In terms of corner or weight balancing, you can spend roughly $1000 on Longacre scales, or the Ruggles scales are around $425 (Pegasus has them). There's also a good article by Mike Piera written some years ago about how to corner balance using 4x6's and a household scale. If you scan the archives, you'll find several people, myself included, who have posted their corner weights after balancing. If you need theory on corner weights, that's been discussed in both the racing and 911 Rennlist email lists over the years, or any number of books cover it.
