[Lumps!] Rear toe is out 5/8" - ANY ideas on what is wrong?


(Roger Mabry) #1

After finishing up the IRS rebuild, I took my '71 XJ6 to my
favorite front end/frame shop for rear alignment. It was Jaguar day
there as there was a 2007 XJ(8?) sedan in there for front and rear
alignment. The owner had owned a '72 S1 previously and we
discussed ‘‘electrical problems’’.

I had a ride and we went to breakfast and received a call while
eating. ‘‘Come pick up the car as we decline to work on it’’.

After talking to the Asst Mgr, he reported the camber as 0 on the
left and 3 on the right and the toe out at 5/8’’. I had given him
the pages out of the Jaguar manual as reference for the S1 Specs.

Since there is no toe out/in adjustment, just the setting
of ‘‘parallel �1/32 inch’’, he was at a loss. He said they had
not ‘‘been into a older Jaguar rear end in 20 years’’ and did not
have any new parts.

Since the 5/8’’ of toe out is the total difference in the front of
both rear tires versus the rear of both tires when sitting , what
could be wrong? The front of the tires are doing a ‘‘snow plow’’ as
in skiing, while going down the road. Also bad for economy.

I had given him the need to have the car at the ‘‘mid laden’’
position of the suspension - or halfway loaded. He did not have the
Jaguar ‘‘setting links - part JD 21’’ to use and just used jacks.

Knowing all this now, the camber can be adjusted by moving the
shims from side to side. One or two shims need to be added to the
left side, but the right has (4-5) shims now. I do not think taking
them all out will be enough to return it to the 3/4 negative +/-
1/4 degree spec? Each shim alters the camber by approx 1/4 degree.

The tires were wearing on the inside before the IRS rebuild and
with that much toe out it is understandable. After owning the car
for 3-4 years, I found out it was in a rear end accident at one
time in the past. I had trouble getting the boot latch to work
properly and discovered the very good prior repairs underneath.

Can the swing arms be ‘‘bent/straightened’’ on the car or are there
other solutions to toe out? Can they be removed and then all the
washers/seals be put back in while the cage is still attached to
the car? I do not ‘‘desire’’ to do this all R&R again but the problem
needs a solution.

When I took the IRS gear section out, one of the front (short)
trunion block bolts was broken and was still in place with the
safety wire. It was replaced and the trunion blocks are flat and
show no sign of any wear. There are two shims behind only the
position of that bolt (in the front only) on the drivers side.

Those shims can cause some of the toe out, but the most they would
be would be .007-.010 thick each. I only put them back where they
were before the tear down. I do not have any refences as to the
amount of shims to use to cause or correct toe out.

I plan to remove those two shims as the manual shows shims that
behind both bolts per side and then get the car re-measured at
another willing front end/frame shop.

Looking for ideas of things to check???–
'71 XJ6 383/200R, '72 XJ6 LT1/700R,'74 XJ6 383/700R
Glendora, CA, United States
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(cadjag) #2

In reply to a message from Roger Mabry sent Thu 31 Dec 2009:

Roger:

I just had a couple of ideas.

My keyboard is acting up!!! It is acouple of seconds behind my
fingers!!!

  1. You mentioned that one of the traction arms was bent. That
    could skew one wheel out.

  2. String some chord tightly at the t he center of the reare wheel
    up to the center of the front and measutre the deflection

Apologies for the ousy spelling and structure.

The delete key will not allow me to edit.
Carlsim–
Carl Hutchins 1983 Jaguar XJ6 with LT1 and 1994 Jeep Grand
Walnut Creek, California, United States
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(lockheed) #3

In reply to a message from Roger Mabry sent Thu 31 Dec 2009:

Roger,

From my notes:

Front Shims: 1/16’’ Shim changes Camber or Caster by 0.25 degrees.

Rear Shims: 0.020 Shim changes Camber by 0.25 degrees.

I don’t know the thickness of the inner trunnion shims nor how much
they change the toe of the rear for each shim. As I understand it,
the fulcrum shaft holes in the cage basically determine the toe of
the rear assembly. The swing arms are assembled into the cage with
the fulcrum shafts and the inner trunnions, and then, the shims are
added as near equal on each side as possible to fit the
differential snuggly between the inner trunnions. Now, one removes
the fulcrum shafts and bolts the trunnions to the diff. with the
shims that made everything snug. Done correctly, the fulcrum shafts
should slide easily in and out of the assembly with the trunnions
bolted up tight against the differential. The shims between the
inner trunnion and the differential may be able to change the toe
some small amount provided there is some play in the cage fulcrum
shaft bearings. I had a bit of a toe problem at the rear when I
converted to the outboard rear brakes. Because I sold the 3.54 diff
that came with the assembly and used a our CW rebuilt 2.88, the
shims as they were installed with the 3.54 apparently were not
quite right for the 2.88. The fulcrum shafts did not go in easily,
but I thought because I had replace the shims exactly as they came
out, that was the way it should be. After finding out that I had a
toe problem, I did manage (with some difficulty) to pull the
fulcrum shaft on the problem side out enough to get the trunnion
bolt out and add another shim. Guess what, the fulcrum shaft now
slid in easily, and once everthing was buttoned back up and the
alignment checked, the toe on both sides was now within spec. - all
done without removing the cage assembly.

Of course, if the rear were tweaked in the accident, the cage may
no longer be true, and/or not mount square in the chassis, and/or
one of the swing arms may have been bent a bit. I guess there are
a lot of variables here and it can only be said that one must start
with straight and true parts. I’m not sure how you would check the
cage for correctness unless you had another to compare it to, but
the swing arms should be dimensionally mirror images of each other.

I’m sure others, that have had more experience with the rear cage
assembly than I, can jump in here with their knowledge and help.–
89 XJS Cpe/97 LT1/4L60E, 96 XJS Cv 4.0, Austin TX/Miami FL
Miami, FL, United States
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(lockheed) #4

In reply to a message from Roger Mabry sent Thu 31 Dec 2009:

Roger,

If your left rear camber is ‘‘0’’, you need to remove two .020 shims
from between the shaft flange and the differential flange to make
it go negative 1/2 deg. Conversely, on the right side with a + 3
deg, removing the 4 or 5 shims will bring you closer to 1 to 1.5
deg +. Some of the shims may be thicker than .020, so you need to
figure out how many shims to remove to get to the slightly negative
camber. In short, adding shims will increase + camber, and
removing shims will make it more - camber.–
89 XJS Cpe/97 LT1/4L60E, 96 XJS Cv 4.0, Austin TX/Miami FL
Miami, FL, United States
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(Andrew Robertson) #5

In reply to a message from Roger Mabry sent Thu 31 Dec 2009:

Hi Roger,

castor shims will not compensate for that kind of error - and
assuming that the inner trunnion bearings are good, the radius arms
have little to do with it either because they have quite compliant
bushes. Your info points to a bent bottom arm. I suggest you get
yourself some more and set them and the ones you already have up
and take some really accurate measurements and reassemble the IRS
with the 2 straighest and squarest ones.

Rear toe-out of that magnitude is a highly unstable and undesirable
condition that must be addressed. You are not in snow plough mode -
you are in the more serious splayed out mode.

I often had to put up with an on-spec total rear toe but with a
slight side thrust - in fact my race car was like this - had a
small amount of total toe-in but one side very slightly toeing out
and the other toeing in more than enough to compensate - that’s no
problem but 5/8 inch is a major.

Good luck and let us know how it goes.

Cheers, Andrew Robertson, New Zealand–
The original message included these comments:

Since the 5/8’’ of toe out is the total difference in the front of
both rear tires versus the rear of both tires when sitting , what
could be wrong? The front of the tires are doing a ‘‘snow plow’’ as


Andrew Robertson
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(Roger Mabry) #6

In reply to a message from Andrew Robertson sent Wed 6 Jan 2010:

Still working on the issue. Found out that you cannot get accurate
measurements of the swing arms in the car.

Tried to measure from several points and can find no problems yet.I
found a local shop that does Jag IRS work for hot rods and he has
many good used parts - alrady verified.

I have carefully looked the car over for signs of the rear end
repair to the frame, floors etc and there are no signs. It may just
have been a sheet metal/bumper deal.

Will probably just drop the IRS and take it in the bed of a truck
to him for measuring and replacement of the bad parts.

Funny thing is - the car drives very straight and has no handling
problems! Just the wear on the inside of the rear tires as the
notice something is wrong.

Will let you all know what was found when it is properly adjusted.
The RH camber is strange but both the camber and tow out will be
fixed.

Due to emails from the Forum members, I have a method now of
setting the camber with the IRS out of the car. Starting with the
camber and working outward should point out the problem(s).–
The original message included these comments:

bushes. Your info points to a bent bottom arm. I suggest you get
yourself some more and set them and the ones you already have up
and take some really accurate measurements and reassemble the IRS
with the 2 straighest and squarest ones.


'71 XJ6 383/200R, '72 XJ6 LT1/700R,'74 XJ6 383/700R
Glendora, CA, United States
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(Phil Schaefer) #7

In reply to a message from Roger Mabry sent Thu 31 Dec 2009:

I had an experience in this matter. I bought a 14 yr old etype that
wore rear tires and skipped (!) sideways on wet roads.
I finally noticed that when parked the suspension raised itself
(and dialed in + camber) after going forward, and lowered itself
with neg. camber, in reverse. Pretty sure it was a toe-in problem!
I found that the heavy control arm (swing arm) on one side had been
bent forward in a rear end accident (PO) and knocked out of true
about 3/4’’, measured at the ends. I bought and installed a new part
(23 yrs ago- wasn’t too pricey) and have enjoyed driving the car
about 90,000 miles since.
Someone mentioned that the cage may have been bent. I think the toe
is most closely related to the swing arms or their mounts at the
center section. I would guess it is possible to rebend the arm, off
the car, I suppose with a hydraulic ram.
I was absolutely inexperienced with the IRS, but was able to
replace the fulcrum bearings etc, with the IRS in place on the car,
with no issues at the time or ‘‘down the road’’.
Phil 72 etype (86-present), 84 VdP ('93-'07)–
The original message included these comments:

After finishing up the IRS rebuild, I took my ‘71 XJ6 to my
favorite front end/frame shop for rear alignment. It was Jaguar day
After talking to the Asst Mgr, he reported the camber as 0 on the
left and 3 on the right and the toe out at 5/8’’. I had given him
Since the 5/8’’ of toe out is the total difference in the front of
both rear tires versus the rear of both tires when sitting , what
could be wrong? The front of the tires are doing a ‘‘snow plow’’ as
in skiing, while going down the road. Also bad for economy.
with that much toe out it is understandable. After owning the car
for 3-4 years, I found out it was in a rear end accident at one
Can the swing arms be ‘‘bent/straightened’’ on the car or are there


Phil Schaefer
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(Roger Mabry) #8

In reply to a message from metalover sent Thu 7 Jan 2010:

Phil, thanks for the information.

I believe it is one or both of the swing arms that are
twisted/bent. Tomorrow the car has an appointment with a shop with
electronic alignment equipment. He can tell me which side is out
and possibly other important information.

You are correct, changing the swing arms is not tough, just a PITA
to get all the washers and seals in correctly and without hurting
the seals. I had them all out when changing the center section with
the new gears. It is much easier to just drop the IRS than to R&R
the swing arm(s) in the car. Plus, there is a method of setting the
camber with the IRS out of the car. It is easier to get the correct
shims in place while on the ground that doing the camber shim R&R
in the car.

Should know more tomorrow…–
The original message included these comments:

I found that the heavy control arm (swing arm) on one side had been
bent forward in a rear end accident (PO) and knocked out of true
about 3/4’’, measured at the ends. I bought and installed a new part
I was absolutely inexperienced with the IRS, but was able to
replace the fulcrum bearings etc, with the IRS in place on the car,
with no issues at the time or ‘‘down the road’’.


'71 XJ6 383/200R, '72 XJ6 LT1/700R,'74 XJ6 383/700R
Glendora, CA, United States
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(lockheed) #9

In reply to a message from metalover sent Thu 7 Jan 2010:

‘‘I think the toe is most closely related to the swing arms or their
mounts at the center section.’’

Phil,

And, the mounts at the center section are - welded into the cage.
So, if the cage is not square with the body, how can the rear
alignment be correct??–
89 XJS Cpe/97 LT1/4L60E, 96 XJS Cv 4.0, Austin TX/Miami FL
Miami, FL, United States
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(Andrew Weinberg) #10

I don’t think the cage is the issue here- it’s far less substantial than the pivot brackets bolted to the diff. Even so, the Jag manual is pretty specific that any shimming of those brackets to help with sliding in of the long shafts be equal front and rear. There’s no true toe adjustment on these suspensions like you might see on later Corvettes. With these flat surfaces (brackets to diff) any attempt to influence rear toe by altering front/rear shim amounts will only ultimately result in loose screws and loose brackets.

My money is on a tweaked lower arm…

Also, if the cage were not square to the body, the whole assembly would be cocked in one direction. In that case, wouldn’t you see toe-out on one wheel and toe-in on the other???— On Thu, 1/7/10, lockheed awe1@comcast.net wrote:

From: lockheed awe1@comcast.net
Subject: Re: [Lumps!] Rear toe is out 5/8" - ANY ideas on what is wrong?
To: lumps@jag-lovers.org
Date: Thursday, January 7, 2010, 4:32 PM
In reply to a message from metalover
sent Thu 7 Jan 2010:

‘‘I think the toe is most closely related to the swing arms
or their
mounts at the center section.’’

Phil,

And, the mounts at the center section are - welded into the
cage.
So, if the cage is not square with the body, how can the
rear
alignment be correct??

89 XJS Cpe/97 LT1/4L60E, 96 XJS Cv 4.0, Austin TX/Miami FL
Miami, FL, United States
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[forums.jag-lovers.org]–
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(cadjag) #11

In reply to a message from A sent Thu 7 Jan 2010:

A:

That is partially why I suggested a comparison of wheel base
measurements, side to side.

And it could be a slightly cocked cage plus a bent arm to create
the toe out on each rear wheel, if that is the case.

But, if Roger is having a really accurate measurement, these things
should be illustrated. I think tht is one of the basic measurements
that any alignment shop makes, or should make.

Carl–
The original message included these comments:

My money is on a tweaked lower arm…
Also, if the cage were not square to the body, the whole assembly would be cocked in one direction. In that case, wouldn’t you see toe-out on one wheel and toe-in on the other???


Carl Hutchins 1983 Jaguar XJ6 with LT1 and 1994 Jeep Grand
Walnut Creek, California, United States
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(Roger Mabry) #12

In reply to a message from cadjag sent Thu 7 Jan 2010:

Hopefully we are only hours away from the shop results. This car
has spacers behind the front wheels due to the XJ40 wheels.

Without the spacers the tie rods hit the wheels and the tires do
not have enough room and rub on the steering arms. So, the normal
methods of measuring toe out with a straight board/metal piece do
not work well.

I hope to get a complete measurement of the car and the places
where the problems live. Then anyone can correct those problems
with new parts.–
The original message included these comments:

That is partially why I suggested a comparison of wheel base
measurements, side to side.
And it could be a slightly cocked cage plus a bent arm to create
the toe out on each rear wheel, if that is the case.


'71 XJ6 383/200R, '72 XJ6 LT1/700R,'74 XJ6 383/700R
Glendora, CA, United States
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(JAY COOLE) #13

ever find the issue with rear toe?
mine is out as well. though not as bad.
see pic for alignment #'s
any help/suggestions on how to correct would be appreciated


(Roger Mabry) #14

Yes, there was a “bent” part in the IRS. Note the photos…!

I have a hot rod shop that does all to Jag rear ends. He fixed the part …Note%20gap%20on%20RH%20from%20block%20for%20drivers%20side|690x412

The gap was wrong on the drivers side due to the prior accident.