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I have an 86 951 and I had it professionally aligned. I’ve only ever driven my 951 so I don’t have anything to compare it to. At slow speed my steering feels fine, more less direct, but at high speeds say over 45 miles an hour I can turn the steering wheel left and right about an inch each way and I don’t get much movement from the front wheels. I have checked all my bushings I even replaced the steering shaft when I did my brake booster replacement. I ate arms are also rebuilt and there is no play in my will bearings. I think it may be my alignment but it seems like the steering should feel more direct. Can any of you with power steering give me an idea of how my car should feel at the higher speeds? I run 36 pounds of pressure in my tires as well, I have varied the PSI a few pounds up-and-down without much difference in steering feel.
Its been over 4 years since I deleted my power steering. When I had it, it always felt "numb" (like too much assist). So I removed the p.s. belt and drove. WOW! I loved it at higher speeds, but found the fluid came out of the reservoir within 15 mins & made a mess.
May I suggest you drain the fluid. Then drive at higher speeds. Then report back, to see if the problem has gone away?
I have an 86 951 and I had it professionally aligned. I’ve only ever driven my 951 so I don’t have anything to compare it to. At slow speed my steering feels fine, more less direct, but at high speeds say over 45 miles an hour I can turn the steering wheel left and right about an inch each way and I don’t get much movement from the front wheels. I have checked all my bushings I even replaced the steering shaft when I did my brake booster replacement. I ate arms are also rebuilt and there is no play in my will bearings. I think it may be my alignment but it seems like the steering should feel more direct. Can any of you with power steering give me an idea of how my car should feel at the higher speeds? I run 36 pounds of pressure in my tires as well, I have varied the PSI a few pounds up-and-down without much difference in steering feel.
Sounds like something is wrong.
Steering feel is very subjective - you'll always get different descriptions of how it seems to different people. But I would say that on my car, the steering feels more precise once you get moving at speed. A common complaint of the 944 steering is a lack of positive feel in the centre...in other words there's a tiny bit of movement in the centre that has little to no effect. Some people refer to it as a dead zone. I've heard people say that it's normal, but the fact is that steering racks do wear, and when everything else is eliminated, it could well be the rack. It's just that most of the used ones out there are in similar condition, and not many people are willing to drop the $1500 on a factory rebuild. I'm not even sure if they are any better tbh, or if they just replace the seals like everyone else. I'm on my third steering rack, which came from a nice low mile car and it's nice and tight in the centre. But the previous two were a little loose.
Whatever about the condition of the rack, and inch each way sounds like way too much. Did you get the alignment specs? What about the tires - age, condition? Also, don't forget the steering rack bushings. I doubt that's your problem but it's often overlooked. I'm not sure how you went about checking your bushings, but I have often missed things before when trying to move things by hand. Sometimes it's just hard to see movement and if you're in any doubt about when any bushings were replaced, it's no harm to just replace them for piece of mind.
similar thing here too, small "dead zone" in the middle, little less than inch in total. im guessing thats normal. yours might be a little too much. i have changed to newER (968) rack, new u-joints, tie rods, bushings, a arm ball joint etc.. no new wheel bearings yet.
Compared to our Mazda5 minivan, my 951 power steering feels slow, heavy, and less precise at low speeds. On the highway, it’s very smooth but more on-centre dead area.
I read once that German car manufacturers purposely put in a little on-centre play. They call it “sneeze factor”. Something about travelling at very high speeds on the Autobahn and sudden small jerks on the wheel
Did you end up replacing the entire rod, or just the inner/outer ends? Did that resolve your on-center play?
The inner had the slop so the replacement part is the whole rod. I did not know I had on-center play until they were replaced. The shop told me I had 3/4" play when I took the car in for a wheel alignment after I dropped the crossmember for other work. The steering response was much tighter afterwards. I'll take the car for a ride this evening and report back on how much play I feel now.
IMHO 1" is not normal or acceptable. Do you really think Porsche would have called 1" of play good enough when the car was new? I don't think alignment is going to be the answer. I would suggest you get a friend and check for total play while the car is sitting still, engine off. Have the friend apply movement to the steering wheel and check all the various joints for play. That would be the shaft U-joints, the tie-rod inner and outer bearings, the wheel bearings, and the input versus ouput motion of the shaft into the top of the steering box. That will help you identify any mechanical components that are shot. And since you say it feels OK at low speeds I'm going to hazard a guess that you won't find any significant play while sitting still. Which will lead to a cause that only occurs at speed. I'm going to guess that at speed, the valving in the power assist is not activating properly and it takes that much movement to get things going.
Regarding the little bit of play at center, reading the current on-going thread about Depowering a Power Rack reveals that there are parts in the system that twist a small amount to open the ports for the power steering fluid pressure to act. (OttoMechanic, please confirm my thinking on this) The reason it is such a long thread is that those guys want to get that little bit of play out of their racks, as run without power assist, and have gone through some creative iterations to do so. But it appears that a power rack does have just a little bit of play coming off center. The de-powered rack on my 944R certainly does. I would quantify it as maybe a 1/4" of movement of the wheel. And apparently Porsche did accept that small amount of play as the price to pay for power steering. BTW, the power rack on my 928 does not show any play off center. I guess that is what $55K in 1986 got you
Going back to the OP, you could experiment by temporarily removing the pulley to your power steering pump and going out for a test ride. If it is the valving in the rack, you may find that the play is much less pronounced with the pressurized fluid taken out of the equation. If that is the case, you can do a Search here on Rennlist. There is plenty of history about various options for rack replacement/rebuilds, etc. Or possibly, your power steering pump isn't keeping up.
944/951 steering should feel very precise. There was no dead zone or play in the steering in any of the ones that I've owned (which is several) except when there was a problem. Here are some things to check:
tie rods, outer AND inner joints can get loose
the steering rack mounts. If they go bad, the rack itself will shift around while you steer and produce a huge dead zone.
There is a little cover plate on the steering rack which contains and spring and piston. These put tension on the rack to eliminate free play. Check that yours is still in place.
The rack gear itself could be worn out. With the car stopped and idling, point the wheels straight and measure the dead zone. Then turn the steering wheel 1 rotation and check the dead zone again. If the dead zone is smaller, your rack (the rod inside the steering rack&pinion assembly) may be worn.
If everything is correct, the steering should have direct response. As a side note, power steering and manual steering have the same precision, it's just that the manual steering gives you a different sensation. I've driven all 3 kinds (manual, power, and depowered).
This is the cover with the piston under it - in this picture it's called "guide pad and piston"
Picture from www.Arnnworx.com (he makes great special tools for Porsches)
What tire and wheel combination are you running, if you have gone with some other set up from stock and
"scrub" has changed that will have an effect on how your steering will feel
tires are potenza re 11 and relatively new, and I do believe I’m running 225 up front and 245 rear. I have the Fuchs wheel option. I run 36 psi all around.
I rebuilt the “A” arms and rubber bushing was in excellent condition. However I don’t know the conditition of the tire rods, though visually they look in good condition and have no play I can feel while under the car while someone above turns the wheel.
Wheel Bearings have been checked, repacked, and retightened accordingly.
Steering shaft has been replaced with a new unit.
All the bushings “appear” in good shape, meaning I can’t get any visual slop and all the rubber is nice and firm yet plyable.
I have new top hats and struts.
As for the steering rack, there I will need to look further into it. The plate that can be removed so tension can be applied to the system, is there a tutorial for examination and setting it up?
05-21-2018, 10:28 PM
How should steering feel ?
