[bombfactory]

Hi guys - My car has always had what I think is too-heavy steering. Recently I completely re-did my entire steering system - installed a rebuilt rack, all new lines and reservoir and re-sealed the pump. Nothing is leaking now but my problem, although slightly improved, still persists:



Just after startup, before the car gets up to temp, the steering feels fine and boost feels normal at high and low speeds / rpms. A few minutes later, once the car has fully warmed up, the steering feels heavy and underboosted.



On Flash's recent Ortega run, with temps well over 100˚, it felt like I had manual steering in the twisties. Not fun.



Anyone else run into this problem and / or can you suggest a cure? Is my fluid getting too hot and not doing its job? Did I botch the pump reseal job?

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[94SilverCab]

I suggest that you purchase a case of Newcastle and invite yourself to Flash's house, then offer him the "opportunity" to drive your car. he will be so dissatisfied with the handling that he will complletely dismantle your entire car down to the last bolt, fix everything, and have it put together by the time you drive off into the sunset...



Jay

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[flash]

funny stuff. i would be happy to take it for a drive though. i told him he needed to bring down the bmw too, as that is the feel he is looking for. then i could see if it was even possible.

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[jfrahm]

I would suppose the pressure relief valve in the pump is sticking open and the system pressure is dropping. The cold fluid maintains pressure OK but once hot and flowing a bit better it is bypassing the valve and your system pressure is too low for proper assist. Offhand I do not know if this can be serviced in situ.

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[bombfactory]

Ha thanks Jay - yeah I'll get down to the Garage Mahal soon and have Flash take it for a spin - though he likes his steering gorilla-arm heavy so he'll probably love it!



I thought the pressure relief valve was possibly the culprit in my original rack and that's why I swapped it out for a rebuilt rack from AutoZone. Now that I'm still having the same issues, the problem most likely lies elsewhere. Maybe the pump just isn't cranking out enough pressure...?

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[flash]

lol - while i do like it heavier than most, it's because i want to feel every input at the wheel, and not just be "pointing" the car. the BMWs i've had all felt too light. i never knew exactly where the tire was in relation to side load and bump. the denali isn't bad, and the SL550 is pretty decent, though a little light. as a touring car, it's fine though.



but if i knew what you were targeting, i could then tell if you could get there or not.

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[biotechee]

Perhaps the rebuilt rack was rebuilt improperly? Doesn't Autozone have some sort of ridiculously long warranty period for rebuilt steering racks? If so, I'd be inclined to take it back if I had the opportunity to easily remove it....



I know it's not fun to remove and replace something again, but you never know.

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[bombfactory]

The rack I got from AutoZone turned out to be a 944 rack. Have not been able to determine if it is functionally different in any way to a 968 rack - other than the casing around the barrel part looked different and the steering shaft no longer lined up so I had to adjust my steering wheel. The rack fit fine in the car, but the new 968 pressure hose I got from Pelican (before I knew I was going to receive a 944 rack) is too long and has to travel an 'S' path, instead of going straight, to bolt up.



I figured once I replaced everything steering related and freshened everything in the suspension, including new front struts and M030 swaybars with new bushings, my steering problems would be gone. Still feels like major understeer though!



I recently had the alignment done and plan to take it back for some adjustments - the guy set it up with too little negative camber and I have virtually no cornering grip. The front end 'pushes' and starts to lose lose traction (understeer) when I'm trying to have some cornering fun. I know the right alignment can make the car understeer less in fast corners, but could it also make the steering feel lighter in normal driving situations?



Jim - swapping the rack was not too complicated, but no picnic either. I could probably do it again in 1/3 the time as my first go-round. I decided to keep my original rack instead of turning it in for the core charge, so I may have that one resealed - tho it was not leaking - and put it back in.



Flash - I've been driving BMWs (M3's mostly) for 15 years so that's certainly what I'm used to. This is the first Porsche I've ever driven. It's entirely possible that nothing is wrong and this is the way 968s are supposed to steer, but... I don't want to believe that! The steering feel I've got is just not good at all - I shouldn't have to fight with the car to get it around a corner. I'll come down one of these days when you have some time and you can take it out on some twisties.

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[flash]

the short answer is "yes"



the longer answer is "it really depends on a lot of other things"



pop down one evening with the bimmer. let me take it for a spin. that will give me a reference point for what you want. then on the next night we can do the 968. the wife is in moscow, so this is a good week.

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[bombfactory]

Flash I'm good this week unless it's a soccer practice night (mon. & wed). I'll give you a call.

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[flash]

sounds like tues and thurs then

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[tamathumper]

@bombfactory, It shouldn't be that hard, I could drive my 968 with one finger,... I just haven't decided which one. <img src="/forum/images/smilies/968/biggrin.png" class="smilie" alt="" />

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[jfrahm]

It could also be the pump itself which seals poorly with hot fluid and cannot maintain pressure.

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[bombfactory]

The problem, whatever it is, is definitely heat related. Just after cold startup the steering weight feels right - light at parking lot speeds and 'normal' (I know that's a relative term) around town. It's not until everything heats up that the heavy, underboosted feel creeps back in.



I was thinking that since the pressure hose now doesn't seem to fit right - the 'gearbox' part on a 944 rack seems to be about an inch closer to the pump than on a 968 rack (unfortunately I didn't compare them when they were both out of the car) - so instead of going straight it has to make an 'S' shape to fit, which brings part of the hose up closer to the engine by a few inches. This might be heating up the fluid more than the cooling coils - and maybe the seals in the pump too - can handle. Too-hot ps fluid might be my whole issue.



To test the theory, first I'll try some heat insulation on the hoses. I don't want to invest in a 944 pressure hose just yet - first, I'm not sure if it's any different, and second, the rack has to come down to install it. Don't want to go there quite yet.

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[flash]

when you pop by, i might be able to hook you up with heat barrier material

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[bombfactory]

Flash I'm in the 968 today - you home tonight?

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[flash]

yup

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[94SilverCab]

Don't forget the Newcastle <img src="/forum/images/smilies/968/smile.png" class="smilie" alt="" />



Jay

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[bombfactory]

After a visit to the Garage Mahal Puppy Kennel last night, Flash has verified that there is definitely something wonky with my steering. The prescription includes new tires, a proper alignment at West End in Gardena and some aluminized heat barrier wrap around my ps hoses - we'll see if this keeps the ps fluid cool and the steering fully boosted.



Bonus - finally got a chance to drive Flash's car. Now I might have to get me a CS steering wheel too...

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[flash]

lol - funny how slippery that slope gets



yeah. he's not crazy. there is definitely something going on. i don't think there is much happening in the power steering itself, but we'll see. the tires definitely are hard (6 years old). that will make it sketchy and resistant. the alignment he just had done doesn't look right either. the caster looks wrong, and maxxed out, which will also make it resistant. it really feels like a truck. it just doesn't want to turn in. once he gets a proper alignment, complete with corner balance, i think it will resolve a lot of the problem. they may have had to add a bunch of caster to correct a corner weight issue. if it's off too far, which is possible after lowering the car, then it will pull. they would then have to add caster to correct that. that then adds a lot of steering resistance.



it will get there though in the end

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