Help please - height differences

cjoenck · 06:52 PM

This evening I looked at my '91 964 from the back and noticed that the driver's side appeared to sit higher than the passenger side. I measured and sure enough, the drivers side sits about 1/2 in. higher than the passenger side in the rear.

Now curious, I measured the front and in the front the passenger side sits about a 1/4 lower than the driver's side.

So what's going on here? Bad springs, bad shocks, worn... ? How does this geometry work?

Thanks much for any insight.

Flieger · Flieger's Garage

Could be a corner balance issue, or non-level floor or camber settings.

If you get it the car do the heights even out? You do not have any luggage in it at the moment, right?

cjoenck · 07:55 AM

The car is 100% stock. There is no luggage in the car and I measured from a level floor. The car was corner balanced / adjusted about 5,000 miles ago, so that could be it. It has 80k on the clock and these may still be the first set of shocks.

Would a failing shock / spring be visible like this?

And yes, tire pressure is correct at all wheels....

Thanks.

Flieger · Flieger's Garage

If you have high-pressure gas-charged Bilstein dampers, then a bad "shock" could affect ride height. Your car should have these so that is a possibility, but the springs have a much greater effect on ride height than the damper gas charge.

cjoenck · 04-24-2011, 06:51 PM

Someone on Rennlist suggested the height difference may account for driver's weight and measuring with a person in the driver's seat, all is well again.

So are the stated tolerances measured with a person in the driver's seat or for an empty car?

Flieger · Flieger's Garage

That is what I meant by "corner balance issue". Corner balance means having each corner supporting it's "proper" weight- basically spreading the load amongst the 4 tires. The car can still sit level if it had only three wheels, like a 3 legged stool, but it would not handle well.

Corner balance is done with the driver in the car, so if the car is balanced with the driver and the driver then gets out to look at the car, the ride height will be off.

cjoenck · 04-28-2011, 01:26 PM

Thank you Flieger for your patience. I guess, I did not put it together well in my head. The car was corner balanced about 5,000 miles ago. I just did not know that corner balancing is done with the driver in the car. I was also surprised that 200 pounds could make a difference of 1/2 in in height.

Flieger · Flieger's Garage

Well, it should be done with the driver or a couple sacks of cement adding up to the driver weight in the driver seat. If they did not do that, then the corner balance will be off when you are driving but good when you get out.

The thing is, since the mass distribution of the car is not symmetric side to side, if you want to get equal diagonals, then one corner might have a slighty different ride height than the others whent he car is balanced and level. Your variation sound like too much for that, though.

Flieger · Flieger's Garage

I wouldn't worry about a 1/2 inch difference in ride height so long as I knew the corner balance was good, the car was handling to my liking, there known to be no damage to any suspension components, and there was no severe tire/fender rubbing during cornering. Looks are not my first priority, though, what with my fiberglass fenders.