Jaguar XJ-S/XJ12: Centering Steering Rack and Column

getawheel

Site Donor 2021
Joined
Oct 30, 2018
Messages
557
Location
Gainesville, FL
Long post with some background, but maybe it’ll help someone. I wish somebody had explained it to me; I had to figure it out.

A common issue with the Jaguar XJ-S is a misaligned steering wheel or an off-center steering rack following replacement of the rack. Some people notice this when making sharp turns and others find it while trying to align the front end. I inherited this issue from the previous owner and finding no well-documented solution, I figured one out for myself.

As we all know, steering rack remanufactures are known for their fine workmanship. In the case of this era of Jaguar, remanufactured is all that’s available. In my case, the previous owner had a Maval rack installed. The input shaft on the rack has a total of eight different ways the gear can line up with the rack, but a has master spline on top so the steering column can only connect one way.

It should go without saying that the input shaft was installed improperly in this rack, which lead to the column being connected with the steering wheel off center by half a turn. To compensate, the installer centered the steering wheel by adjusting the tie rods. The result was a straight steering wheel, but a seriously unequal turning radius. The rack was off center. I had 2.25 turns to the left and 1.5 turns to the right.

The obvious answer is to disassemble the rack and properly place the input shaft so it lines up with the column. Unfortunately, that’s a lot of work, and beyond most people’s abilities. Not to mention simply removing the steering rack is an all-day job. I would have done it if need be, but it’s not entirely necessary. You can center the rack and steering column and achieve the proper turning radius by rotating a splined joint in the intermediate portion of the column found in the driver’s footwell.

First, get under the car and remove the grease fitting in the rack. Looks like this:
D01637F0-D05C-4B2A-8E34-36EE38978CF6.jpeg

(Not my photo; found it on Google)

Take a 3/8” punch or something of the like and insert into the hole like so:
C0F0FBEE-5FFD-49DE-B563-BBD522086846.jpeg

Then, turn the steering wheel until you feel the punch fall into a detent. This is the rack’s true center. Disregard the position of the steering wheel and road wheels at this point.

Look under the dash and find this joint between the upper column and the intermediate shaft:
D049EDFF-E7A4-4957-A43A-74FD6A5016F3.jpeg

The lower end of this joint, near the firewall, can only connect one way. The upper end can rotate fully and connect in any position.

At this point, find what should be center with the steering wheel. Test out turn signal canceling, column locks with the key removed, etc. until you’re confident it’s in the right spot. This will be absolute center when you’re finished. When you remove the ignition key, the column should lock with the steering wheel dead center. Leave the column locked and get under the dash.

Take the pinch bolt out of the upper end of the universal joint and gently tap the joint off of the upper steering column. Once it’s loose, get under the car and manually center the rack, verifying with your punch or other tool that you’re on the detent. Go back under the dash and slip the joint over the splines. Put the bolt back in, but don’t tighten it all the way yet. Turn the steering lock to lock a couple times to verify no binding or other issues are present. Remove the ignition key and lock the column back to center, check and verify the rack is still centered. If so, tighten the pinch bolt down and adjust the tie rods so that the road wheels are pointing straight. Now is a good time to check the toe measurements.

This whole thing could be avoided if 1. The numbskulls rebuilding steering racks would do their job properly, and 2. Mechanics replacing steering racks would read the Jaguar service manual and verify everything was in order. Apparently neither of those things happen, as almost every XJ-S owner I’ve spoken to has had this issue (steering racks are basically consumable wear items on these cars).

These steering setups are very simple to align when everything is assembled properly. With the detent in the rack, there is no question of center, and no excuse to have an off-center steering wheel.

ETA: Next time you have to replace the rack, unless you’re really lucky, the input shaft will be in a different position relative to center and you’ll have to do this again. But it’s still much simpler than correcting the input shaft by disassembling the rack. If you go to that trouble, may as well have rebuilt your old rack yourself and done it right.
 
Joined
Jan 18, 2020
Messages
1,776
Location
United States
rack doctor is notorious for this

the rack in the pic is a ZF from a 93 and up and should give you no trouble if that’s the one you have. the original adwest ones are a piece of junk
 
Last edited:
Joined
Sep 27, 2015
Messages
3,560
Location
USA
Inspect the rebuilt rack before installing and send it back if it's wrong.

Also a general rule on rebuilt parts: never ever turn in your core part until after the new one is on the car and working.

Moving the tie rod ends to take half a turn out of the steering wheel is terrible mechanicing. That is for when it is few degrees off of straight ahead.

If the car has an air bag or anything electric on the wheel, it is very important to keep turns of the wheel in sync with turns of the rack, or the clock spring will break.
 
Last edited:
Top