hot66

Hi

I have a '95 C4 cabrio

I'm having, what I think, are issues with heavy / dull steering at slow speed ( 30 mph)

When driving at 30mph, the steering when at straight ahead feels very heavy / dull & takes a bit of effort ..... but bear in mind I'm comparing this to my 1973 2.4S that has beautiful steering feel at all speeds

When up to speed , 60mph + , on twisty roads it feels fine. On the motorway, in the straight on position, it again feels a bit lifeless

Is this dead, heavy feeling just a characteristic of the car, or is it a sign the rack is worn , or the fluid needs changing ?

If it is a characteristic, it might be time for me to change to a C2 !!!

Linnm

911

TRINITONY

Drive faster ..lol..

Mike J

You might want to compare a few cars, plus your front end alignment can really change the feel of the car. For example, you can get the car to be quite darty, or even heavy feeling by having not enough toe (or too much). Have you also checked your tire pressures.

The other way is to drive some other 993's to compare...its hard to comment what "heavy" is without driving your car.

My car at slow speeds has a more solid heavy feeling, but its never really tougth to steer...but its definitely not super light. However, at speed it does lose a bit of that heaviness but again its never light.

Cheers,

Mike

nile13

Steering effort will be affected, at the very least, by tire pressure, alignment, size of the front bar. I would also check to see if there's enough power steering fluid in the reservoir.

hot66

tyres are at 36psi all round

power steering fluid level is at the top

alignment was done recently and at the time I got them to add a bit more caster to try & give a bit more self centreing to the steering

Steve Weiner-Rennsport Systems

JMHO,

Tire pressures should mirror the car's weight distribution for proper handling. That means lower pressures in front since it carry 35-40% or so of the car's total weight and higher pressures in the rear as those carry 55-60% of the car's weight. This is why Porsche makes their recommendations.

More caster increases steering effort; less caster lightens the steering effort. If your caster settings are higher than the factory recommendations, you likely created the problem,...

Conversely, taking a little caster out of the car will make it easier to steer and there will be no loss of stability with the proper toe settings.

I'd be redoing your alignment for the solution.

hot66

thanks for the in fo Steve

the tyre pressures of 36 all round are as recommended by the sticker on the door ... 17" wheels 36 all round. The stick does say 44 rear, 36 front if using narrower 16" wheels though ??

Interesting regarding the caster. It wasn't really any different before adding a very small amount of extra caster to help with the self centering.

I've spoken to my local specialist & we're going to have a play around with different caster settings to see what, if any, difference they make. Also going to change fluid in the PS too.

The only other think we think might have an effect, is my car has done quite a lot of miles under previous owners of motorway driving. Is there any possibility that the steering rack might have worn more in the straight ahead position if most of it's work has been done there ?

Many thanks for all your help so far

techman1

You are describing my exact symptoms. Sometimes after a low speed curve, I will need to pull the steering wheel back to center. This is on a '95 with everything to my knowledge stock, 56K miles.

hot66

an update .. of sorts

took the car out again, this time without having driven my early car just before. I'd also put 37psi in teh fronts & 38 in the rears

To be honest, 1st 10 miles or so of driving whilst things are warming up, the steering feels fine, if a little heavy, but nothing to worry about. For this reason I'm ruling out geometry issues

Then, up to speed & really giving it some on the rough twisty roads the steering feels nice.

Come into a town, and back down to 30mph and it feels heavy again.

I'm now pondering on 2 thoughts ...... 1st being that it just feels heavier after giving it a thrash as it feels so much nicer / lighter at high speeds.

2nd thought is that maybe, after a while of driving it is getting heavier as the temps increase ?


Is it possible for the PS fluid ( I assume never been changed since 1995 / 101K miles ) is not performing as well once hot ?

Quadcammer

I tend to think the factory tire pressures result in a car that understeers worse than a trabant, but that was just my experience.

36fr, 38r at this point.

polaris 993 sport

I have had an issue with this same problem-at slow speed more to the left-steering is hard-plus the wheel hisses a bit. This has been an issue for more than five years. Had a new rebuilt rack installed-then my mechanic who was a whiz rebuilt it again. Then had a new reservoir tank and hose installed. No luck. I have done some mods but this started way before. Porsche has no clue. I am going to a new shop close by I was recommended. I have had the car since new-so I know what it should feel like. Come on gang-solve the issue!
The car drives like a dream at speed-but I hate the slow speed issues. Feels like an rs than power assisted at slow speeds.

nile13

What are you talking about? Trabant oversteers like crazy

Oh, and the tire pressure. I would think the car would want more than 2 PSI difference front to rear. My guess for tomorrow autocross is maybe 36-42 cold and go from there. This is for street Pilot Sports or whatever bricks I currently have on the car. This is with what i assume should be fairly neutral current setup (M030 sways, M030 springs with HDs, very street alignment, 235/265 tires).

I would, again, look at the fluid level and operation of power steering pump. I would also listen for noises while turning the wheel all the way in both directions when the symptoms show up. The problem clearly sounds temperature related, so I would start there.

hot66

just done another 100 miles, this time really paying attention to the weight of the steering.

I'm now sure it gets heavier during the journey, which indicates it's a temperature thing.

I'm going to get the fluid changed as I have no idea when that was last done.

We'll then see if that makes any difference

Shake

I'm no mechanic, but I'd think checking the pressures in power steering system, when you're experiencing symptoms, might be useful.