One thing I've come to notice on my 05 STR is that at a stop or very slow speeds sometimes when I turn the steering wheel quickly on a surface that's a bit rough like say pavers the steering seems to be underpowered and the wheel stumbles a bit in my hands as though there's not enough power coming out of the hydraulic pump to overcome the resitance of the surface.

It's not really a bad issue but I was a bit surprised.

Is this normal?

Bob S.

 

Bob S. be sure to read the whole thread! https://www.jaguarforums.com/forum/s...+pump+additive

 

Have had this EXACT problem in my 05 for a loooong time. Will try the additive from Jag when I get to it. Some have had very good results.

 

Thanks for posting this but ...

This is not what I have described. I'm getting no noise that I've noticed. It's a definite shudder one can feel.

I did read through the the 3 TSBs and there are 3 distinct issues. The big one involves a partial rebuild of the rack with a 4 hour allowance for the job. Sure ... I think it will take longer than that out of warranty.

But now I'm informed so I can discuss this with the dealer. Mine seems like the idle is too low to support the load put on the pump and with not enough pressure being produced by the pump you can feel the shudder transmited from the rack right up through the column and to the wheel.

It does demonstrate that the rack isn't an over boosted, no feeling type of steering which is a good thing!

It looks like they reccomend using Mobil 1 synthetic ATF after a rebuild. That's probably for heat related issues and the additive is for de-gumming the broken down fluid that was in there. I'd be tempted to flush the system both before and after their magic elixer has had it's effect to make sure there's none of that old stuff in there. I wonder if it's one of BG's products?

I think I'll flush mine ASAP to preven this noise from showing up.

But ... I saw no mention about feeling a shudder in the column.

Bob S.

 

Bob S. along with the "cooing" that we had experienced, we "felt" a very slight shudder as well. I put the additive in and presto!! I don't know why I did not include the faint shudder to my post in that thread.

 

Ah hah! Thanks for mentioning that.

Well I read all these threads at a very early hour this am so I may have missed it but honestly, it wasn't very prevalent in ANY of the postings or the TSBs. I heard a lot about noises though. This am I will look for a sticker on the reservoir for evidence of already having been treated.

If the seal really is binding that much to cause a shudder it won't be long before it fails so I best get right on this.


Did you switch to a particular brand or synthetic PS fluid?
I use one made by Redline in my race car due to heat issues.

I also wonder if the proceedure quoted in one of the threads as being over $200 for putting the additive in also included a complete power flush of the steering hydraulic circuit?

That might make sense if it prevents the R&R of the rack for a rebuild as outlined in one of the TSBs. That will be a lot more than $200.

Bob S.

 

Try the additive as I suggested before you go through all of this trouble with rebuilding. According to my Jag master tech and others on this forum its supposed to take care of slight shudders and/or noises. May be as simple as that, and you know if you're out of warranty, even if they agree to do it due to a TSB, you'll still get slammed with some kind of cost. I'd say its a no brainer at 12 bucks.

 

Yep, I had the additive put in when I had some other work done. It solved the "cooing" sound coming from the steering wheel. Not sure if yours is the same problem or not though.

 

Mine is exactly the same way. Seemed to happen after I added the PAS additive and replaced some of the powersteering fluid with a Lucas Oil additive. Did you ever solve this?

 

Hope you don't need to replace the rack but keep in mind we have verified that the Lincoln LS rack and tie rod ends will work for the STR and regular S Types. This rack is a bunch cheaper and is available aftermarket.
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I mentioned my results in the before the warranty expires thread.

It's been at least 3 maybe 4 weeks and about 1 tank of gas or 300 miles since they added the magic elixir.

The noise was immediately reduced. It hasn't gotten any better since that time.
I still have a noise. Sigh ...

I noticed an instant improvement in the bump steer effect I was getting but I still need to go in for an alignment adjustment. I think it may need a bit more toe-in.

I haven't noticed the steering judder of late but I can't say it's gone either. I'll try and stay alert. I am going for a bit of a drive the sh*tty roads that induce bump steer once again so I'll have an update Monday.

 

Cool thanks. Keep us posted. Mine's actually an XJ X350, but it seems to have the same damn problems as the S-type!

 

So Bob, I take it that you have ruled out the idle speed variable you mentioned in post #4? Just curious.

 

I haven't ruled anything out because of what I mentioned in my last post.

 

I'm pretty sure on my XJ that it doesn't have much to do with idle speed. I guess what I'm saying is it's not due to the idle falling too low, causing the engine to run rough, etc.

 

I never mean't to imply that there was any issue of the idle speed being erratic. I just wondered if being set where it is the load from the pump was too much when you turn the wheel on certain types of surfaces at slow or no speed.

 

There may be (sorry haven't looked at elec diagrams) a pressure switch (often called PSP) to tell the PCM to increase revs. If there is, maybe it's faulty. Ideas anyone?

 

I have this same squeel and shudder feeling...do you just pour the additive into the power steering reservoir and let it work its way through the system or do you have to completely flush the system and re-fill with the additive and then the proper amount of power steering fluid?

 

Search will get you the answer

 

I'd have to say that I'm no longer noticing any judder effect at all but I do still have a somewhat quieter squeak.

Another interesting thing is the improvement in chassis tracking. This makes me wonder just what the heck is going on in these steering racks?

My symptoms arrived as follows:

1. Judder at slow speeds.

2. The car begins to not track so well with a lot of bump steer.

3. I begin to get the squeek.