Steering is lumpy
 

Hi all - my XJS v12 93 vintage has developed a strange issue with the steering - it's lumpy. Feels like the assistance is coming in then off then in, then off.

Has new tyres correctly inflated, new front springs, greased UJs, and nothing obvious from the MOT. The rack hoses were replaced a few years ago.

Any thoughts??

Thanks in advance!

P.

Hi Pedman

Don't want to state the obvious but have you checked the level of the Power Steering Fluid?

Loose drive belt at the pump?


Cheers
DD

Good timing this post, I felt my steering wheel... pulsing when manoeuvring the car in the driveway, nothing when driving.
Fluid is good, does not seem to be a leak BUT I have put new belts on and have not checked them since they were installed, so thanks I will check the belt.

Good idea. It's fairly common for new belts to stretch a wee bit, and need re-tensioning.

Cheers
DD

Thanks all, fluid seems fine, belt seems tight. Maybe the steering pump on the way out?

Actually maybe the rack mounts? They might be the original ones

Hi Orangeblossom, nothing wrong with asking the obious - they are usually the easiest things to miss! Fluid is fine, belt seems fine as well, but thanks!

Sloppy rack mounts let the road steer the wheels. Quite scary when they are all failed, but when they’re on the way out the steering just feels vague and unresponsive with occasional unexpected darting. Possibly interpreted as assist coming in and going out. What’s the “lumpiness” feel like? Is it only at speed?

Hi JigJag - thanks for the reply. It seems to happen even when standing still, so at least it doesn't sound like the mounts - which is a relief.

Sounds like you take care of your car. One thing that comes to mind for me in your story is the seals in the rack itself? Maybe. If you can (and I'm sure your boots are new), do youse any fluid leaking at or around where the steering rod ends meet the rack? Maybe fluid gets past seals in some area but not escaping the system?

My next thought was the pump itself. Just changed mine. Not so bad as LONG as you simply remove any and everything that's in your way in getting to it... Saves hand skin and your neighbors hearing you curse and swear ---- the XJS invoked human spectacle, ya know,,, lol?

I have a large collection of spanners that have been cut in half to get clearance :-) - along with a large collection of scratches, scrapes, missing skin, etc from fighting around that V12!!
Boots look okay, and there doesn't seem to be fluid inside them - I'm beginning to suspect the pump myself.

One or two others:

1 I think the pump used here is a GM Saginaw unit. Somewhere on the pump is the relef device. An orifice and spring. dirt there can cause odd behavior.

2. Or air in the system. two ways to bleed it.

A. jack up the front. run he engine. turn the wheel lock to lock a few times.
B. More fun way. Go toa large park lot on an off hour. drive several figure 8's. no need to speed, resist the temptation.

They are supposed to be self bleed, but need help at times.

Carl

Here is one for the books...

just returned to the states to pick my 92 from a shop where they replaced the front subframe.

I remembered having pulsing steering the last time I drove it 3 years ago. Checked all the obvious.

The shop showed me the power steering metal tube loop for the cooler attached to the front of the subframe. It was smashed by a rock or some other road debris. Maybe 1/2 mm clearance inside the pipe.

Go figure