Well, I got it all together tonite. I put new rubber parts
in the trans mount and refurbished the center bearing and mount.
The trans mount did not look bad, but I ordered the parts anyway.
The only part that really needs to be replaced is the foam bushing
Part # cbc1324 for $34.00 from S.I.C.P…
Although the old one did not look real bad, the new one seems much
better…less bumping around of the transmission.
The center bearing turned out ok also…the first test drive
had some vibration\rumbling that I think I got rid of by jacking the
back of the car up, starting it,putting it in gear and then loosening
the center mount bolts and then retightening them. I took it for a
short test drive after I did this, and I didn’t notice the rumble,
but it was a short test.
I may still have some, from 2 causes…I put a lot of silicone in
the center bearing mount, so it may be too stiff, and when I removed
the drive shaft I didn’t mark the way the center parts went together.
The Haynes manual tells you to mark the jurid and the trans flange
with paint, but forgets to tell you to mark the center part at the
center bearing…I think mine is off a couple of teeth on the splines
but Im not sure, as I didn’t mark it there.
I wonder how they set these things up at the dealer…how do they
set the center bearing position?
Well, Im tired of spending my nites under the car, with crap falling
in my face, so I think Ill see if it gets better…
I bought new bolts for the exhaust clamps at Sears hardware…they
have some nice grade 8 bolts and the all metal locknuts to put on
the stainless steel clamps…I always wondered why they don’t use
all stainless hardware on the clamps…I know stainless is softer
than regular steel, but couldn’t they make the bolts a little thicker?
The exhaust system sure is a joy to work on on this car…
So back to the questions…
How do you set the center bearing location?
How important is the drive shaft balance?
How do you balance the drive shaft?
Any tips will be appreciated.
Thanks,
Brett
1990 XJ6
Brett Gazdzinski wrote:
Well, I got it all together tonite. I put new rubber parts
in the trans mount and refurbished the center bearing and mount.
The trans mount did not look bad, but I ordered the parts anyway.
The only part that really needs to be replaced is the foam bushing
Part # cbc1324 for $34.00 from S.I.C.P…
Although the old one did not look real bad, the new one seems much
better…less bumping around of the transmission.
The center bearing turned out ok also…the first test drive
had some vibration\rumbling that I think I got rid of by jacking the
back of the car up, starting it,putting it in gear and then loosening
the center mount bolts and then retightening them. I took it for a
short test drive after I did this, and I didn’t notice the rumble,
but it was a short test.
I may still have some, from 2 causes…I put a lot of silicone in
the center bearing mount, so it may be too stiff, and when I removed
the drive shaft I didn’t mark the way the center parts went together.
The Haynes manual tells you to mark the jurid and the trans flange
with paint, but forgets to tell you to mark the center part at the
center bearing…I think mine is off a couple of teeth on the splines
but Im not sure, as I didn’t mark it there.
I wonder how they set these things up at the dealer…how do they
set the center bearing position?
Well, Im tired of spending my nites under the car, with crap falling
in my face, so I think Ill see if it gets better…
I bought new bolts for the exhaust clamps at Sears hardware…they
have some nice grade 8 bolts and the all metal locknuts to put on
the stainless steel clamps…I always wondered why they don’t use
all stainless hardware on the clamps…I know stainless is softer
than regular steel, but couldn’t they make the bolts a little thicker?
The exhaust system sure is a joy to work on on this car…
So back to the questions…
How do you set the center bearing location?
How important is the drive shaft balance?
How do you balance the drive shaft?
Any tips will be appreciated.
Thanks,
Brett
1990 XJ6
Brett:
I have not worked the 1990 year model but I am assuming it is the same as
my 1988 xj40.
Alignment:
The Jaguar service manual gives these instructions for aligning the
propeller shaft.
- Slacken the bolts securing the center bearing to the mounting plate.
- Standing at the rear of the vehicle ‘eye’ the propeller shaft center
bearing and position the mounting just to the left of center. - Tighten the center bearing to mounting plate bolts.
This offset makes sense to me, this has been used on drive shafts with
multiple sections.
Drive shaft balance:
This is very important, but usually a drive shaft does not get out of
balance like a tire because it does not wear as the tire does. In theory if
it was in balance when originally installed it should still be in balance
provided any new universal joint bearings installed were of equal weight.
To get the shaft checked or balanced I would contact a heavy truck repair
shop that makes replacement drive shafts for trucks, these shops should
have the equipment to balance the shaft.
You mentioned in an earlier post not being able to purchase a new bearing.
When you had the bearing out of the rubber mount do you remember seeing any
numbers in the bearing? There are bearing companies that can cross
reference almost any bearing by number and supply a replacement. If you do
not have the number you can still match by dimensions. If an exact match,
meaning OD or thickness does not match by a few thousands of and inch, was
not found you still are not out of luck. The critical dimension on this
bearing would be the ID where it is pressed on the shaft. If the bearing
was a few thousands of and inch thicker or OD it would still fit inside the
rubber support.
An example of this: General motors does not supply internal parts for their
alternators any more. I had an alternator on my daughters car with a noisy
bearing. I was able to have it matched exactly by dimensions, cost less
than $15.00, was a very common bearing on some other application.
Let me know how this alignment works.
Arnold Q. Lane
Missouri, USA
1988 xj40 Vdp
Arnold,
Thanks for taking the time to reply…
Date: Fri, 31 Oct 1997 06:05:19 -0600
From: Arnold Lane eagle@inlink.com
To: Brett Gazdzinski <@Brett_Gazdzinski>
Subject: Re: Center bearing fix and tips
Brett:
I have not worked the 1990 year model but I am assuming it is the same as
my 1988 xj40.
Alignment:
The Jaguar service manual gives these instructions for aligning the
propeller shaft.
- Slacken the bolts securing the center bearing to the mounting plate.
- Standing at the rear of the vehicle ‘eye’ the propeller shaft center
bearing and position the mounting just to the left of center.- Tighten the center bearing to mounting plate bolts.
Well, before I did anything to it, I noticed that it was way off
to one side…It was almost touching the side of the tunnel.
The mount is made in such a fashion as to make it impossible
to mount it in the center. As the shaft was smooth as glass before
I started, it must like it there.
This offset makes sense to me, this has been used on drive shafts with
multiple sections.
Drive shaft balance:
This is very important, but usually a drive shaft does not get out of
balance like a tire because it does not wear as the tire does. In theory if
it was in balance when originally installed it should still be in balance
provided any new universal joint bearings installed were of equal weight.
To get the shaft checked or balanced I would contact a heavy truck repair
shop that makes replacement drive shafts for trucks, these shops should
have the equipment to balance the shaft.
After thinking about it, I am of the opinion that the U joints
must line up in a certain way…the front and back u joints must
be offset by 180 degrees?? I have no clear way to describe this
except to say that the U joints will allow the shaft to bend a
certain way when in a certain position, so if you offset the front
and back u joints, the vibration should cancel out. If you put
them in phase, the shaft would have a tendency to jump up and
down.
I think I’m 20/30 degrees off. So I will have to get under the
car again and remove the center exhaust section and drop the
front shaft and re align it per the marks I made on the ends,
and see how it lines up with the u joints…
It sure would help if someone knew\looked at the u joints
and posted how they line up.
Anyone working on the driveshaft will save a lot of grief
if they are careful to mark the center section of the shaft
as well as the ends.
(I always find out the hard way…)
You mentioned in an earlier post not being able to purchase a new bearing.
When you had the bearing out of the rubber mount do you remember seeing any
numbers in the bearing? There are bearing companies that can cross
reference almost any bearing by number and supply a replacement. If you do
not have the number you can still match by dimensions. If an exact match,
meaning OD or thickness does not match by a few thousands of and inch, was
not found you still are not out of luck. The critical dimension on this
bearing would be the ID where it is pressed on the shaft. If the bearing
was a few thousands of and inch thicker or OD it would still fit inside the
rubber support.
Yes,Arnold, it did have numbers on it, but it was not bad, so
I just re greased it. It may pose problems to actually replace
it as it looks like its bonded to the fragile rubber mount.
The best thing to do would be to re grease it so it never fails…
I don’t think it has any force on it, it goes from getting dirt
in it or the rubber mount tears. It looks like this…
side view…
_ _
)(
)(
The shaft goes through the center…the rubber tears at the thin
points where there are holes through the rubber to make it softer.
This is for anyone who has not seen it…yet…
An example of this: General motors does not supply internal parts for their
alternators any more. I had an alternator on my daughters car with a noisy
bearing. I was able to have it matched exactly by dimensions, cost less
than $15.00, was a very common bearing on some other application.
Yes. A better plan is to re grease it before it fails…most
of the bearings that I’ve run into have the rubber seals that you
can pry out…I did this on my old alt. bearings…the Jaguar
is due…If you get it before the wear starts, you can triple
the life of the bearings.
Let me know how this alignment works.
Thanks for the info…Ill keep the list posted…
Arnold Q. Lane
Missouri, USA
1988 xj40 Vdp
Brett
1990 XJ6
Brett Gazdzinski wrote:
Well, I got it all together tonite. I put new rubber parts
in the trans mount and refurbished the center bearing and mount.
The trans mount did not look bad, but I ordered the parts anyway.
The only part that really needs to be replaced is the foam bushing
Part # cbc1324 for $34.00 from S.I.C.P…
Although the old one did not look real bad, the new one seems much
better…less bumping around of the transmission.
The center bearing turned out ok also…the first test drive
had some vibration\rumbling that I think I got rid of by jacking the
back of the car up, starting it,putting it in gear and then loosening
the center mount bolts and then retightening them. I took it for a
short test drive after I did this, and I didn’t notice the rumble,
but it was a short test.
I may still have some, from 2 causes…I put a lot of silicone in
the center bearing mount, so it may be too stiff, and when I removed
the drive shaft I didn’t mark the way the center parts went together.
The Haynes manual tells you to mark the jurid and the trans flange
with paint, but forgets to tell you to mark the center part at the
center bearing…I think mine is off a couple of teeth on the splines
but Im not sure, as I didn’t mark it there.
I wonder how they set these things up at the dealer…how do they
set the center bearing position?
Well, Im tired of spending my nites under the car, with crap falling
in my face, so I think Ill see if it gets better…
I bought new bolts for the exhaust clamps at Sears hardware…they
have some nice grade 8 bolts and the all metal locknuts to put on
the stainless steel clamps…I always wondered why they don’t use
all stainless hardware on the clamps…I know stainless is softer
than regular steel, but couldn’t they make the bolts a little thicker?
The exhaust system sure is a joy to work on on this car…
So back to the questions…
How do you set the center bearing location?
How important is the drive shaft balance?
How do you balance the drive shaft?
Any tips will be appreciated.
Thanks,
Brett
1990 XJ6
Brett:
Sorry about a second reply to the same post but I forgot to address the
alignment of the drive shafts. I have not read any instructions about this
in the service manual.
On all multi segment drive shaft I have worked on the proper alignment was
to align all universal joint spiders together. This means if the spider at
the transmission output shaft is orientated vertical, all other spiders
should be vertical. If someone else knows anything different I would be
interested in hearing from you.
Arnold Q. Lane
Missouri, USA
1988 xj40 Vdp
Thanks for the info David, I hope to work on it tonite…
I now have 2 replys…one(Arnold) says to put all the u joints
at the same locations, and your reply that says to offset them.
Offhand, I would think that they should be offset…but I could
be wrong…logic is no help…if they are offset they will cancel
out, or have twice the resonant frequency…if they are lined
up, they will both be going at the same rate and be in balance
(not one speeding up while the other slows down). I still lean
towards offset…
Brett>Date: Fri, 31 Oct 1997 10:36:47 -0500
To: Brett Gazdzinski <@Brett_Gazdzinski>
From: David_Berman@BayNetworks.COM (David Berman)
Subject: Re: Center bearing fix and tips
Brett, I need to get under my car this weekend. I will look at the
driveshaft and let you know how the U-joints line up.
I believe conventional (single-cardan) U-joints are normally used in pairs,
offset by 90 degrees. The reason is not to keep the shaft from jumping up
and down but rather to cancel out variations in angular velocity. When a
single-cardan U-joint operates at any angle greater than zero, the angular
velocity of the output side varies over a revolution. Two U-joints offset
by 90 degrees will cancel out this variation as long as input and output
angles match. That’s why differential nose angle is so critical on cars
with live rear axles. If the vehicle design won’t allow the angles to
match, double-cardan (constant-velocity) U-joints must be used.
-David
Brett,
Have you set up your center bearing offset to the right or left? The
instructions in the “Owners’ Edition” manual (which may have been the
source for a quote by one of the list members) indicates positioning just
left of center, but in my car it is definitely all the way to the right.
The Haynes books says very little on the subject, but the photos appear to
me to show the bearing significantly to the right.
-David