Mk10 power steering issues

I’ve been trying to get a few miles on the Mk10 (4.2 with late Adwest power steering box), but it’s resistant to staying on the road, in spite of the many, many hours I’ve spent working on it. Had it on a 20 mile run today, and steering is an issue for several reasons.

  1. New power steering problem - pump has been noisy before at full steering wheel stops (normal I think for this pump) but now steering balks and pump squeals when trying to turn at idle - works ok when rolling. No help with revving engine in park. I had tightened the steering box some, but loosened back off a full half turn, thinking I might have over-tightened it - it did not help. I’m thinking a weak power steering pump. No leaks and fluid is full. Pump is a used unit from a 420G that I parted many years ago. The Cardone Saginaw 20-6086 rebuilt pump may be an option? Anyone think this could be a steering box issue?
  2. The car does not track well at highway speed, and the steering feels stiff, the wheel not returning on turns. All worn suspension components have been renewed. I know the upper column bushings that I put in are tight with a bit of binding, and I recently got some oil in there, but it’s hard to believe that’s all it is. I had it professionally aligned recently and it drives better, but the mechanic could not give me the + caster that I wanted, the suspension maxed out at about about zero caster and camber (close to what Jaguar specified), no more shims to move. There is no sign of any body/suspension collision damage, and this appears to be all that was allowed in the design.
    The car now runs and stops well, nice with it’s overdrive transmission, but it must drive better for me to want to use it on a regular basis. Certainly wouldn’t be relaxing to drive on the freeway.

Its not normal for the steering to be at all stiff, mine is very light, and literally could be driven with the little finger.

This is a bit disconcerting, there is also too much freeplay at the wheel for my liking

(This is a replacement box for the original one, which was also light, but was worn and leaked badly)

Most likely it is in the box or pump

As you describe a possible pump fault, I would suggest dismantling the pump and inspecting for wear, as it is a very simple item, with hardly any parts. Just check you can get a seal kit for it

The box is much more complex

I would jack the front up and go through the steering cycle with engine off, and on

see if you feel any tightness, if you do unpowered, it probably isnt the pump

Tony,
Good suggestions. I will do as you suggest.

As to the pump, does the seal kit offer anything other than leak control such as internal o-rings which could restore power? I haven’t been in one of these pumps before. The “rebuilt” Saginaw pumps advertised by Cardone are not expensive, and I’m inclined to get one before converting the car to a non-runner, but I don’t know about the quality of the rebuid. I can always send it back. A mechanic friend at a local museum who I helped upgrade his Mk10 steering has a local rebuilder for the Varimatic, and I could send that out. I’ll be talking to him on Monday.

Thanks - will let you know how it goes, although I might be a little while with some out of town trips coming up.

Hi Ron, before you disassemble anything, make sure your power steering belt is tight and not slipping.
Regards,
Allen

My Mk2 was much as your car when I started working on it. I did the box, tie rod ends, pin/bush kit, uni joints, steering column etc. What really improved it was a thorough alignment done by me with a roofing square, g cramps, macrame string and bits and pieces. Shops will do their best but may not have the shims and the patience and these are critical. I made some up and swapped them around to suit. At this point the steering lightened up considerably. I run 34psi in the front. It doesn’t need power steering as it’s properly set up!
Pictured is the crude rig at my XJ6 wheel - which steers magnificently.

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“I know the upper column bushings that I put in are tight with a bit of binding, and I recently got some oil in there”

Well for what it’s worth I had this issue when I rebuilt my upper column in my 3.8S. Forgot to lube the upper and lower nylon bushings and the car would not self center. Was able to get some oil in the upper one and maybe the lower one and the problem went away. No other changes made.

Belt is almost new and appropriately tight.

I have home alignment equipment (Fastrax system and a specialty toe-bar) and aligned the car as best can be done with such. There is no way that a home alignment is as accurate as professional laser equipment, assuming competence of the operator, certainly not a given in my town! However, I think we can get pretty close.

I found it impossible to get the settings I wanted (at least 2 degrees + caster and 1 degree negative camber) because of physical limitation in the front end. All of the caster shims on the driver’s side are shifted to the front already. The passenger side could have a bit more, but they have to match. The other way to get + caster is to add shims to the base of the a-arm at the front, shifting the upper balljoint to the rear, but unless you have shims to remove in the rear base, you induce + camber, not good. My alignment guy is very experienced, does most of the hot-rod and specialty vehicles in town. He was very interested in the factory materials and read all of it. He and I had discussions about trying to get some + castor. He advised against doing machine work to allow for more caster.
Here are the specs from completed alignment:

I hear what you are saying and not discounting it. Still thinking about it. I do think there is more than one problem at play here. Thanks for the input.

Yes, I remember reading your prior comment about that. I’ll lube them again. Haven’t put the horn push back in yet, so it’s pretty easy.
Thanks

Expect there is more to your issue. The alignment work on mine really did finish it off after all the other actions. Good luck with it.

I just ordered a remanufactured pump, $68. I’ll try that for a first step, but I won’t be surprised if I wind up doing a rebuild on Varimatic box as well.

You can get to the upper one without too much trouble but I do not know a way to get much lube to the lower one without disassembly.

With 0° caster you’re not likely to get much self centering action but it shouldn’t be stiff, especially around the center position.

If there’s no other option I would remove the upper ball joints & get 1 or 2 mm machine off the rear edge, that would give some space for more shims in the front.

Sorry to hear about your problem, but am sure it can be fixed. I have the Adwest box in 5 cars, and 4 of them are perfect in all regards. On one G there is a bit of movement at the sttaight ahead position. I.e. the steering wheel can be turned a few degrees in both directions without the car leaving the straight ahead trajectory. As soon as I turn the play is gone. I have tried adjusting the slotted screw at the top, many times, but can’t get it perfect as on the other cars. None of them leak.

That had occurred to me, and I think it’s a good idea, if there is enough meat on the unit. I think I need to get the stiffness out of the front end first, then we’ll see if it needs it. I’ve been thinking about the lower ball joints, and wondering if I took out too many shims. Will get it up in the air today and check that.

That’s helpful, and I appreciate the encouragement.

Ron,
I’m using the generator driven pump with the Adwest box. I believe the PSI is substantially lower than the pump you are using. I actually like this because I have more road feel. Even with the lower PSI, I have none of the issues you are describing. I suspect that the pump is the issue.

No issues getting a good alignment here.

If you decide to rebuild the box, I still have the address of the shop that I used and the LeMay sent theirs to.

Micah

I had it up in the air today, and I can move the front end through it’s range without acting like Hercules. It’s a heavy suspension, but I don’t feel anything that I can describe as significant binding. I do feel what I presume to be the steering box tighten up a bit as it goes away from center, but I think that may be normal.
No resistance or balkiness jacked-up with the engine running. When I took it for a test drive, it seemed improved when everything was cold, but when I got back from my 5 mile test loop, the stuttering balkiness was back - it feels clearly like a hydraulic problem to me. While the lower ball joints might be a little snug, I can’t see that as a cause of any of my problems. No change in the lack of steering centering. I always want to find one cause for the issues, but I’m thinking more here.

My plan is to replace the pump, see what that does, and send the steering box for a rebuild if that doesn’t solve it. It’s one of the very few things not replaced or refurbished on this car, but still having regular failures. The speedometer died yesterday and the left fuel pump today.

Micah, I’ll be talking to Dale from the LeMay on Monday, but if you have that rebuilder contact info handy, I would love to have it.

Sure:

PS Systems Inc.
1180 NW 163’rd Dr.
Miami, FL. 33169
(305) 474-8705
Power Steering Parts | P.S. Systems Inc. | United States (pssystemsinc.net)

Ask Dale how the conversion worked out. Hope my old box performed well.

Micah