SC does not move tightly with steering. Why?

911sc79 · 09-05-2005, 12:32 PM

I own a low miles 79 SC Coupe. All the suspension and steering parts are original as they came from the factory. Tires are new S-03.

When I move the steering the car does not react immediately to steering input. It reacts softly and loosely. I would say it reacts more as you would expect a Buick to react than a Porsche. I recently drove a 80 SC and the car reacted immediately to steering movement. Mine fells like something is soft somewhere.

When I turn in a curve the body does not lean much.

What could be the problem?

Al S · 09-05-2005, 12:54 PM

Same thing happened on my 83SC when I switched to the new Avon 500 tires. The Falkens I had on previously had very stiff sidewalls, It made the car feel like it was on rails. I miss that

.

I had to change my driving habits to accomodate the softer tires; minor sharp steering corrections are no longer possible. The up side is that the ride is much less harsh, and quieter.

North Coast Cab · North Coast Cab's Garage

If all the parts are original they are probably all worn. The tie rods and ball joints could lead to those issues.

911sc79 · 08:08 PM

My car has very low miles so I strongly doubt the parts are worn. On the other hand they are 26 years old so it is quite possible that they have deterioreted over the years.

The 80 SC I drove had the same tires so that cannot explain the drastic difference in feel between our cars.

Michel J · 09-05-2005, 06:25 PM

I had a similar problem with my car. I found that the steering rack had loosened up. Scarry thing! Might be worth a closer look.

Michel

drsimonwong · 09-05-2005, 06:26 PM

I think it's the age of your components. Even if it's a low milage car 26 years of holding up 2700lbs will take it's toll.

Alginment may be an issue. Then check/change your tie rods and shocks and bushings and maybe torsion bars.

Simon

lateapex911 · 09-05-2005, 08:21 PM

Bushings, sway bars and shocks. Check for slopy bushings, broken or loose sway bar bushings and links, and loose shocks. Push on the fender of the car a few times and observe the reaction. It should rise and stop at it's normal level. Anything more means the shocks are due to be changed out.

Torsion bars are likely just fine, but after 26 years rubber deteriorates, even just sitting there, so the bushings are suspect. Not guaranteed that alone is the issue, but it's worth a close inspection.

I assume you checked the air pressure of the tires.

Also, excessive toe in will dull steering response, and toe out will increase it.

Wil Ferch · 09-06-2005, 02:42 AM

Don't ignore the obvious.....you say "new" tires....

I get the same feeling.....front and rear....that goes away only after 500-750 miles on new tires, depending upon tire brand and type....

- Wil

livi · 09-06-2005, 03:39 AM

I posted a while ago with the same complaint. Answers were similar as above. So far I have changed the rear shocks from original Boge to Bilstein standard. Tremendous change in ride quality overall but (obviously) no improvement regarding the imprecise steering feeling. Plan to change shocks front next week and take a better look at sway bars and bushings.

Instinctively (newbie) I would say ball joints, bushings and tie rods would be among the most likely culprits (as stated above).

Bob's Flat-Six · Bob's Flat-Six's Garage

If your car is stock, US ride height , shocks are softer, no Turbo tie rods , etc , etc, And the SC you drove recently was set up better this is probably what's going on.
The new SO3's are a good start and do feel a little funny when new. Mine wanted to follow lines in the pavement when new at speed. Their better now with miles on them. So start there, it's free.

If you want to spend some money ( loads of Fun ) then I would take it to a good shop and put it up on a lift and have a good look and make a plan from there. My 80 SC has 86K miles and it's had it's original Bilsteins replaced with Sports rear & HD's up front.
Turbo tie rods, 26 mm rear T bars and the S03's. on 7's and 9's and of course lowered and aligned. Even adding sport seats makes a big difference.

Even though SC's are pretty much the same stock when you start tweeking them they become altogether different cars.

Superman · 09-06-2005, 07:42 AM

The S03's are not the problem. Their sidewalls are firm. Your suspension is the problem. A professional alignment by someone who knows how to set THESE cars up with other-than-factory settings is needed. Also some (0r all) of your suspension bushings need replacing. Turbo Tie Rods are a common and important upgrade. They take ALL the play out of the steering linkage. No rubber. Metal to metal from the steering wheel to the steering knuckle on the wheel. And shocks will also make a big difference. If you do these things, with the alignment coming last, your car will be completely transformed. The biggest wild card is who sets up the alignment.

flipper · flipper's Garage

Quote:

Originally posted by Wil Ferch
Don't ignore the obvious.....you say "new" tires....

I get the same feeling.....front and rear....that goes away only after 500-750 miles on new tires, depending upon tire brand and type....

- Wil

I agree, when the new tires break in, it will feel alot better.

911sc79 · 09-06-2005, 08:34 AM

The other car probably had better suspension as the owner tracks it a few times a year. The steering felt much more tightly connected to the car. It reacted very quickly. Like a go-kart.

Tires are not the issue. My car felt the same way with my old tires.

When I push on a fender the car moves down a bit and comes back to original height as soon as I stop pushing. I am pretty sure my shocks are OK. When I drive on the road my car does not move up and down like worn out shocks usually do.

The problen is when I move steering right and left. The car does not react tightly to steering input. It lags behind. Probably some parts have aged and are not as tight as they used to be.

Also, when my car stands still, I can move the steering a few degrees right and left without any movement of the wheels. Is this normal?

arcsine · 09-06-2005, 09:57 AM

You last statement would lead one to question the tie rods and or the steering rack. Stock SC's came with a rubber dampener in the tie rod which certainly deteriorates over time. Common replacement is the all-metal tie rods from the turbo cars. If your car has low mileage, the rack is probably not worn out but would not be harmed by pulling and re-packing with new grease. Makes the tie rod swap easy to boot. Do this, get and alignment and things should be markedly better. I'd toss in new shocks just because you are there.

Par911 · 09-06-2005, 09:59 AM

Quote:

Originally posted by 911sc79
The other car probably had better suspension as the owner tracks it a few times a year. The steering felt much more tightly connected to the car. It reacted very quickly. Like a go-kart.

Tires are not the issue. My car felt the same way with my old tires.

When I push on a fender the car moves down a bit and comes back to original height as soon as I stop pushing. I am pretty sure my shocks are OK. When I drive on the road my car does not move up and down like worn out shocks usually do.

The problen is when I move steering right and left. The car does not react tightly to steering input. It lags behind. Probably some parts have aged and are not as tight as they used to be.

Also, when my car stands still, I can move the steering a few degrees right and left without any movement of the wheels. Is this normal?

That sounds exactly like a loose steering U-joint. Tighten the U-joints in the front trunk/smugglers box, if they are loose then your steering will be less responsive.

lateapex911 · 09-06-2005, 09:59 AM

Well, certainly it wouldn't be a premature call to look at, and/or replace the tie rods, ball joints and steering rack, and the steering knuckle in the smugglers box. (long shot)

anthony · 09-06-2005, 11:58 AM

The push test IMO does work very well on a 911. On my 85K mile car I had original shocks. One was weak and the other was totally blown yet the car passed the push test.

I'd definitely swap out the original shocks. Bilsteins or Konis are a nice upgrade. I'd also inspect the rack, a-arm bushings, sway bar bushings, tie-rods, and ball joints for play/wear/cracking.

Wil Ferch · 09-06-2005, 10:35 PM

With the add'l info posted...and folding-in my own experience, I say this:

1.) Still tires....wait until you got 700 miles on them and report back.
2.) An "imprecise" lane change feeling....like "loosenes" during the transition? Then....look at getting new shocks all-around.

All this assumes general good condition of tie-rod ends, ball-joints, etc...

My "perfect" low mileage original car exhibited the same tendencies until tires broke-in and (finally) shocks were changed.

- Wil

HardDrive · 09-06-2005, 10:57 PM

The mileage is not relavant here. The original tie rods have rubber bushings that are probably toast. I had the same problem with my 82 when I got it, so I had JW put turbo tie rods on mine. Dramatic difference.