This weekend I will be replacing a differential front pinion
seal on a 93
XJ6. Having never replaced this particular seal before I would like to
know if there is any call for special tools and what is the
easiest way to
replace this seal. Do I have to completely remove the drive shaft? How
about the exhaust? Thank you for any suggestions that might help me in
this weekends project.
(continued from previous message)
If you can, measure the torque required to turn the flange through the gear
backlash. This would require an inch-pound torque gauge, and the movement
is only about 5 degrees. I didn�t do this. However, if you can, measure
this torque and record it. On a new assembly, it�s supposed to be 35 � 55
inch-pounds. The idea is to restore the preload at the end of this process
to the same figure as before the seal replacement. Alternatively, turn it
through the backlash by hand and try (!) to remember how it feels.
Insert two bolts into the flange bolt holes and arrange a breaker bar or
large screwdriver to bear against these and the floor or part of the
subframe to resist the torque needed to remove the pinion shaft nut. Remove
the pinion shaft nut completely. It may be held in place with locktite, and
is crimped to resist loosening, so it’s tough to get off. Remove the washer
beneath the nut, if possible. Using a three-jaw puller, draw the flange off
the shaft (it�s a very tight fit). Using the seal puller, insert one hook
under the lip of the seal and pry the seal out, levering against the edge of
the differential housing. DO NOT INSERT THE PULLER FAR ENOUGH TO SCRATCH THE
INSIDE SURFACE OF THE SEAL HOUSING DURING REMOVAL!
Thoroughly clean the seal housing surface and the pinion shaft splines and
threads. (See pictures) Thoroughly clean the input shaft flange, including
the splines. Inspect the sealing surface of the flange. If a groove is
worn in the sealing surface, use 600 grit or finer sandpaper moistened with
motor oil to polish out the groove, working around the flange evenly. Try
for as smooth a finish as you can get, and avoid putting any flat spots in
the flange sealing surface. (See pictures) Clean the flange again, and put
it in an oven at 250 degrees F.
Obtain or improvise a seal driver that will fit over the extension of the
pinion shaft and will seat in the outermost circumferential groove of the
seal. I used a piece of plastic drain fitting (see pictures) that had the
right dimensions, about 2 7/8� O.D. and 2 5/8� I.D. Ensure that the
adhesive sealing material on the differential side of the seal is intact and
uncontaminated. Ensure that the differential seal housing is clean and dry.
Offer up the seal to the housing and drive it home, I used a plastic hammer
and went around the seal as best I could to drive it in evenly. It must be
driven completely and evenly into the housing, so that the adhesive sealant
on the inside surface is compressed against the bottom of the seal housing.
The pinion shaft is in the way during this process, probably the Jaguar tool
uses the threads on the shaft to seat the seal.
Remove the pinion shaft flange from the oven, apply some grease to the rear
edge that enters the seal, to the sealing surface, and to the splines, and
install it onto the pinion shaft so that the marks on the pinion shaft and
the flange line up. This will ensure that the flange splines are in the same
shaft splines as original. Tap it lightly into place as far as possible,
enough so that you will be able to engage the pinion shaft nut and washer.
I was not able to push it fully home before it cooled down, I had to draw it
into position with the nut. Things are rather sloppy at this point, since
the bearings are not seated and the shaft can wobble about. Fortunately, the
seal has a flexible surround and can accommodate some movement, but try to
keep the flange centered in the seal as far as possible.
Place the washer on the pinion shaft and engage the pinion nut threads.
Tighten the pinion nut to pull the flange home, but STOP TIGHTENING PRIOR TO
LINING UP THE MARKS. During this process try to keep the pinion shaft
centered in the seal by holding it with your hand, it�s sloppy as stated
previously until the nut is nearly tight.
Remove the nut and the washer. Brace the flange to resist rotation. Apply a
bead of RTV to the inner face of the flange, under where the washer sits and
around the shaft. Install the washer. Apply Locktite to the threads of the
pinion shaft where the nut will be. Install the nut and as it comes close
to the final position, stop frequently to check the position of the marks.
When the marks are back in line they were originally, stop and test the
torque required to turn the shaft through the backlash. This should be
similar to what was measured or felt originally. If it’s very loose, check
the marks again and think why this might be. TURNING THE NUT PAST THE
ORIGINAL MARKS IS NOT RECOMMENDED AND THERE IS NO GOING BACK IF YOU DO. If
the diff was noisy and the torque was way too low you can do this in an
attempt to improve the situation, but be aware that you may destroy the
pinion shaft bearings at substantial cost and inconvenience. Once the crush
sleeve on the pinion shaft is compressed by doing this, loosening the nut
again will not result in satisfactory operation.
Reassembly is the reverse of removal, as they say. Top up the differential.
This worked O.K. for me, I haven�t had diffy troubles as a result. Be
careful with the propeller shaft and flange connections (75 ft-lbs),
vibrations can result from sloppy work, or even from careful work.
Remember, if you have this done at a shop, you�ll be able to blame them for
trouble and not yourself��
'90 Vanden Plas Majestic (DAVZCAT)
'55 XK140 OTS