911SC rear suspension problem
07-16-2001, 06:36 PM
#1
3rd Gear
Thread Starter
Join Date: Jul 2001
Posts: 3
Likes: 0
Received 0 Likes
on
0 Posts
911SC rear suspension problem
I recently purchased an '80 911SC - I guess you can call me a Porsche newbie. After taking it out this weekend (from 100mph on the freeway to ragging about on local bumpy streets) I noticed after parking that the right rear of the car was resting nearly an inch lower than normal (left side is ok at normal height). I didn't notice any major problem when driving and everything seems to be in place underneath. I am unfamiliar with this type of torsion bar suspension (I'm slowly getting familiar with the car as a whole) and assuming that it must have gotten bent or out of line somehow. Any thoughts on this problem? I've searched the list and couldn't find anything similar. Thanks for any advice.
07-16-2001, 07:45 PM
#2
Technical Specialist
Rennlist
Lifetime Member
Rennlist
Lifetime Member
Torsion bar trivia....if you know anyone who has a late 1990's Ford Explorer, it uses torsion bars in the front.
In the rear...it sounds like this happened suddenly, ie, it wasn't that way when you bought it. It's possible that your adjustable spring plates bolts could be loose, which could cause an inch of height change. Although torsion bars can sag over time, I haven't heard of torsion bars breaking, but I guess it's possible. Or, your tire is way low on air
In the rear...it sounds like this happened suddenly, ie, it wasn't that way when you bought it. It's possible that your adjustable spring plates bolts could be loose, which could cause an inch of height change. Although torsion bars can sag over time, I haven't heard of torsion bars breaking, but I guess it's possible. Or, your tire is way low on air
07-17-2001, 11:28 AM
#3
Addict
Rennlist Member
Rennlist Member
Hello
66 Oldsmobile Tornado. Longest torsion bar in Automtoive use. American Milstones.
Torsion bars are do or break. Porsche torsion bars do break starting with corrosion years back. Never heard they brake while driving. Just an other mysterius thing
Porsche are mostly looking a "bit" unleveled, I think to compensate the drivers wight or the streets are all a bit hanging to the right to drain the water faster ( Usually 2-3° in germany ).
Secound Bill Tire pressure is 2,0 front and 2,5 rear then drive a while and park leveld. Messure the hight from the street to the middle off the wheel arches. They shout be within 1/2" from left to right and within 1" from fron to rear ( over the thump ).
It is also a way to check out Porsche work shops and adjust the chassis to old glory.
Grüsse
66 Oldsmobile Tornado. Longest torsion bar in Automtoive use. American Milstones.
Torsion bars are do or break. Porsche torsion bars do break starting with corrosion years back. Never heard they brake while driving. Just an other mysterius thing
Porsche are mostly looking a "bit" unleveled, I think to compensate the drivers wight or the streets are all a bit hanging to the right to drain the water faster ( Usually 2-3° in germany ).
Secound Bill Tire pressure is 2,0 front and 2,5 rear then drive a while and park leveld. Messure the hight from the street to the middle off the wheel arches. They shout be within 1/2" from left to right and within 1" from fron to rear ( over the thump ).
It is also a way to check out Porsche work shops and adjust the chassis to old glory.
Grüsse
07-17-2001, 12:19 PM
#4
Addict
Rennlist Member
Rennlist Member
A couple things to look at:
1. the spring plate bolts could have come loose cause the right side to sag
2. The right rear shock is bad and needs to be replaced. Test this by applying downward pressure - it shoudl pop right back up if the shock is good.
Either way - take the car to a Porsche qualified mechanic and get the car straight. I suggest new shocks (unless they were recently replaced), a height adjustment to Euro specs, and a 4 wheel alignment and balance at the 4 corners. There is a multi-step procedure for doing this work and your local tire dealer won't know it.
It is amazing how well the car will handle once these things are done.
1. the spring plate bolts could have come loose cause the right side to sag
2. The right rear shock is bad and needs to be replaced. Test this by applying downward pressure - it shoudl pop right back up if the shock is good.
Either way - take the car to a Porsche qualified mechanic and get the car straight. I suggest new shocks (unless they were recently replaced), a height adjustment to Euro specs, and a 4 wheel alignment and balance at the 4 corners. There is a multi-step procedure for doing this work and your local tire dealer won't know it.
It is amazing how well the car will handle once these things are done.
07-17-2001, 01:43 PM
#5
Racer
I second JBH's thoughts. Bring it to someone who specializes in 911 suspensions. I actually just had a somewhat similar issue with my car, it wasn't level (although I couldn't really tell from visual inspection). The passenger-rear was 3/4" lower than the rear driver's side. This resulted in the car being "held up" and balanced by the rear driver's wheel (kind of like a chair with uneven legs). In addition, because the car was lowered (even more than Euro spec) but wasn't level, I had horrible issues with tires rubbing, among other things (alignment). I found a local guy who is GREAT with Porsche suspensions (Mike Holman at Holman Automotive in Eden Prairie, for those in the Twin Cities - he is also a crew member on the Ruf/Porsche race team). The solution was relatively simple. He raised the car slightly and leveled it out (along with doing an alignment)...all for only $70!!! 
There are NO problems and the car handles AWESOME now! 
I've heard of a number of 911's not being level. I suppose there are a number of reasons for this...anything from someone monkeying with it themselves and just messing it up to a broken torsion bar (can happen but don't think it is very common). I would suggest having a Porsche suspension shop take a look...its worth it.
There are NO problems and the car handles AWESOME now! I've heard of a number of 911's not being level. I suppose there are a number of reasons for this...anything from someone monkeying with it themselves and just messing it up to a broken torsion bar (can happen but don't think it is very common). I would suggest having a Porsche suspension shop take a look...its worth it.
07-18-2001, 06:12 PM
#6
6th Gear
Join Date: Jun 2001
Location: Northern Ca
Posts: 6
Likes: 0
Received 0 Likes
on
0 Posts
Had a similar problem with mine. Turns out the front LH side was almost an inch higher than the right. Using a tape measure, I lowered the left front (square 'bolt' in lower A arm) to the same height as the right and all is well. The cars are so stiff that a small difference in the front will show from the rear as well.
07-18-2001, 06:50 PM
#7
Technical Specialist
Rennlist
Lifetime Member
Rennlist
Lifetime Member
Matt,
You should probably have your 911 corner balanced. While the fenders may measure roughly the same, the corner weights can be off, and that can make a big difference in it's handling. If you have a 911SC or newer 911, or adjustable spring plates, it's fairly easy to adjust the corner weights, unless it's horribly out of balance. However, you do need a set of scales, or equivalent, to set the corner weights correctly.
You should probably have your 911 corner balanced. While the fenders may measure roughly the same, the corner weights can be off, and that can make a big difference in it's handling. If you have a 911SC or newer 911, or adjustable spring plates, it's fairly easy to adjust the corner weights, unless it's horribly out of balance. However, you do need a set of scales, or equivalent, to set the corner weights correctly.
