Steering pull

[Guest]

Hi, I am enjoying driving my new (to me!)1986 944 Turbo apart from one rather disconcerting phenomemn.The car can pull to one side without any warning. It only lasts for about a second and can be held with the steering wheel to avoid the car moving of line, but it is quite a strong pull that is felt through the stering wheel. It doesn't happen very often, about twice in a 40 min drive and as I say only lasts about 1-2 secs. It can pull to the left or right.It happens completely at random and can not be induced. It happens when driving staright ahead or 1 - 2 degrees off straight ahead ie not whilst cornering. I thought it may be the wide tyres tramlinning on the road but it happens on both rough and smooth roads. The power steering is fully topped up and there does not appear to be any uneven wear on the new tyres to suggest a tracking problem. Wear in the steering rack around the staright ahead position of the rack ? I am fairly competant around a car but am new to the Porsche marque and wondered if anyone out there could point me in the right direction ? Thanks in anticipation.

 

[944Turbo]

Does sound like tramlining to me, I would try 968 castor mounts and an alignment,
Tony

 

[Fen]

It sounds to me a bit like my car was the first time the poly wishbone bush broke up, albeit mine did it permanently and yours sounds intermittent.

I'd definitely say it's bush related, either the castor one Tony suggests or the front wishbone bush itself.

 

[stevep2000]

If it's intermittent it may just be an alignment problem - found that mine had -ve castor one side & +ve castor the other, wasn't hugely noticable but did make it very sensitve to camber changes in the road which weren't immediately obvious. Problem is though a good alignment will cost you £150+, and if you then need to replace wishbones / bushes etc. you will probably need another one. However, if you take it to a good specialist for an alignment they should be able to spot any problems with wear in the components before spending loads of time doing the alignment. Where abouts are you based?

 

[sawood12]

Glad to hear you are pleased with your turbo!! IMHO the 968 castor mount replacement is a worthwhile upgrade for anyone. The 944 castor bushes are a poor/very compromised design and are likely to be way past their best anyway. It only costs about £70 for the bushes from your local OEM and if you've half an idea how to use a spanner/ratchet is a pretty simple job to do yourself in about an hour or two.

If you use the search function there are plenty of threads about tramlining with several people posting how they cured their particular tramlining problems.

 

[Hilux]

I'd definitely say it's bush related

I concur as its when the wheels are straight so something is slack at that point allowing noticeable movement that then has to be corrected as against a pull on a positive steering force.

Castor/camber will be more road sensistive in my opinion.

 

[mik_ok]

Known points for checking are front wishbone balljoint (which should also clunk occaisionally if knackered) and steering UJ wear, which should give you general slop in steering - you can view uj's where the rod comes through the bulkhead - get someone to wiggle yer wheel and see if it there appears to be any slop.

I wouldn't describe 944's as having particularly wide tyres, but I sure know they can tramline badly. See my thread Over 'Ere Guvnor

You mention the tyres are new - did you put them on? Did this start after you replaced the tyres? Any mention of a geometry check in the cars' history?

 

[sawood12]

The symptoms I had for the worn steering shaft U/J's was excessive steering wheel wobble, as if the wheels were out of balance, for the first 5 or 10 mins of every journey which gradually settled down as the engine warmed as the shaft expands, lengthens and pushes against the U/J's and eliminates the play in them. I can't say I noticed any tendancy to tramline though, but I could have caught it before the U/J's became excessively worn.

 

[Guest]

Thanks very much for all the positive feedback - excellent forum.!

The tyres are new Continentals with only 1,500 miles on and a full wheel alignment was done at the same time by the previous owner.

Sounds as though I need to check the wishbone and castor bushes this w/e. 968 castor bushes are mentioned. Are these different to the standard944 ones and are they a direct replacement ? Can any one recommend the beat manual to get - have heard that the Haynes is no good, some of the CDs on E-Bay can be a rip off and the factory ones very expensive !

As regards new bushes, what is the concencus of opinion regarding OEM rubber or Polybush and the best/cheapest source. The car is mainly to be used for eating up long distances comfortably and quitely rather out right handling performance.

On the subject of noise I have to say that the 944 is not as quite as I had hoped on motorways/fast roads. Tyre noise is very dominant, mainly from the rear - I assume because there appears to be very little trim over the rear wheel arches and any noise is attenuated by the large glass rear hatch and that this a trait of the 944, to be expected from a sports car.

Wind noise also appears high, again from the rear - almost sounds as though the tail gate is open - which it obviuosly isn't - whilst the tailgate seal appears in good condition.
By comparison the engine is incrediably quite - have to use the rev counter to check the rpm - something I've never had to do in the past, always been able to hear the engine !

Sorry for all thw questions.

 

[Guest]

No excessive tyre or wind noise here. My car's really quiet. But it does tramline like a, err, tram.

 

[Fen]

Tyre noise can be horrendous or virtually non-existent on the same car depending on tyres. When I bought my current Turbo I thought it needed a rear wheel bearing. I fitted different wheels and tyres (swapped with the S2 coupe I was selling in fact) and low and behold the noise moved to the S2. They were Avon ZZR tyres and I would never buy them based on that experience.

Wind noise is not generally bad either. Does the sunroof sit flush, is the hatch closing onto both pins and are they adjusted to compress the seal properly? Are there any missing bungs or other open holes in the back panel anywhere like behind the numberplate, where the diffuser mounts or in the wells behind the wheels?

If you need wishbone bushes then you'd be better sticking to standard ones. You can now get the 968 ones separately from the arms (you used to have to buy new arms). The 968 castor mounts are a direct replacement, the difference being the relative proportions of metal and rubber in the component. The original 944 ones are basically all rubber and the 968 ones are a metal housing with a rubber centre. Poly bushes wouldn't gain you anything for a road cruiser and might introduce harshness you don't need, though not in great amounts I'd suggest.

Check the manuals link on Rick's site www.cannell.co.uk.

 

[Fred Hindle]

Possible brake disc sticking.
Cheers,

 

[Suffolk944]

Mine has the wind noise from the rear hatch area though not too excessively. The rubber seal looks pretty flattened in places (another job for the near future!) so probably not functioning as should. Have heard that this can cause wind noise problems in this area.

When I change my original teledials shod with Goodyears for new 17" alloys with Maxxis tyres road roar decreased dramatically.

 

[Diver944]

A new hatch seal can make a world of difference as the rubber gets crushed over time and loses its ability to seal well. A stopgap solution can be keeping it well lubed with Holts rubber lubricant. A tailormade seal can be had for around £40 or some Motor Factors keep large rolls of seal in various shapes that can be much cheaper and bought by the metre. New door and sunroof seals will also help

Pictures of the old and new caster mount are here:

http://www.axux70.dsl.pipex.com/944t/wheels.htm

It's really easy to change them over but be very careful not to mess up the caster setting or you'll need another alignment [8|]

 

[sawood12]

Don't forget some of the noise from the rear could be from the transaxel. Some of the guys on this forum who have stripped out some of the sound deadening whilst chasing weightloss have commented on how noisy the transaxel is.