Fitting New Seals And Bearings In
A Mk1 – Mk3 Diff
By Ulf
Remper in Sweden
Here’s how I changed oil seals in the rear axle on my Zephyr Mk3. If it looks as a work of an amateur, you’re absolutely right! I’m not a certified mechanic, just an average car nut. This is a job I dreaded a bit since it’s the first time I did it, mainly because of the inner oil seals, as they seemed inaccessible at first glance. Turned out to be one of the easy bits. Time will tell if it was a job well done! :) Any comments, ideas, hints or criticism is welcome. It might be of help for others giving this a go themselves. For this axle it’s already too late! *Laughs*
1. The reason for the whole exercise, leaky seals messing up the brakes and the environment. This must come to an end!
.
2. Everything
is of course a lot easier with the axle out of the car and all the brake parts
removed.... First we need to pull out the drive shafts. Tap the edges of the
flange from behind if they can’t be pulled out by hand
3. Here we
can see how the oil has seeped past the inner seal into the hub.
4.
Small pores in the shaft were the old seal sat. It
would be best to find better shafts or have them machined, but as the new seal
has it’s sealing lip a bit different I’m going to take a chance.
5. This is
what used to be bearing grease inside the hub. The nut that holds the hub
in place is secured with a tabbed washer. Bend out the tab first. Both nuts in
this axle sat pretty firm and since the tool I made wasn’t good enough for this
job I had to heat the nut and then hit it with a hammer and suitable drift.
Both nuts are right hand thread by the way.
6. With the
hub nut and tabbed washer out, pull the hub off the axle housing, tapping it
from behind like with the drive shaft.
7. To get
the bearing out of the hub I resorted to my dear sockets and a vice. Find a
socket that fits snugly inside the grease seal so that it can push on the
bearing, and then find two sockets of the same length to make room for the
bearing as it comes out of the hub. Of course anything sturdy enough will do,
the important thing is to get the pressure as even as possible.
8. Take care
not to damage the threads on the wheel nut studs.
9. Then tap
out the old grease seal of the hub. You could probably push out both seal,
bearing and spacer in one go with a suitable piece of pipe or similar
10.
The hub components; Hub, spacer, bearing, seal,
washer and nut.
11.
The hub a bit cleaner with the new grease seal
fitted. When tapping or pressing it in place try to get the load spread out
over the seal as widely as possible as you might damage the seal casing
otherwise.
Now
back to the axle itself. The inner oil seals turned out to be easier than I
thought to change. But first I changed the pinion oil seal that caused the leak
in Pic.1.
12.
Here’s how to loosen the drive flange nut without
the aid of friends. (Nobody else in the garage at the
time....)
13.
The staking in the nut will be flattened out when
you loosen the nut. After pulling off the drive flange pry out the old seal and
tap the new in place. See to it that the new seal faces the right direction!
When tightening the nut, do not tighten more or less than to the old staking!
There’s a collapsible spacer inside the diff that sets the preload in the
pinion bearings. Tightening more can give too much preload and possibly the
bearings breaking up. Less tightening can result in too much lash and a pinion
that wiggles about and gears wearing faster.
14.
Loosen the nuts around the diff head and lift it out
of the housing. It can sit a bit tight so a couple of extra hands is good to
have. It might need a couple of blows with a soft mallet. Try to avoid hitting
with a steel hammer or mallet as cast iron can crack if you’re unlucky. I often
use a polyurethane mallet with lead balls inside. It sounds like maracas but
works great! The plash shield in the picture has to come out. Drill out the
rivets and wiggle the shield out.
15.
Time for the socket set to come out again! Found a
socket that fitted perfectly inside the housing ends. It has to fit as snug as
possible to catch the thin edge of the seal in the housing.
16.
After removing the old seals and some thought this
is what I came up with. A socket (what else?!), some nuts and washers and a
threaded rod. The old seal is top left.
17.
The thin washer behind the seal (black) was ground
to be just a little bit smaller than the seal to allow the seal to be
pulled right to the bottom of it’s seat - the modern seal is a bit thinner than
the original one. The big, thicker yellow washer backs it up and the socket
aligns the seal and keeps it in place and centered. A third nut in front of the
smaller yellow keeps the package together. Uh, at least that’s my own
scientific idea....
18.
After sliding the whole neat package down the
housing you can take the threaded rod end and feel where the seal should sit.
Then take the big washer and tighten it down with a nut. I could feel when the
seal bottomed in its seat quite easily.
19.
Hard to tell from the pic, but it’s there all right!
With newer seals of a different type it can be a bit hard to tell which way to
fit it. The general rule is tightest end inwards, facing the oil.
20.
The splash shield was put back using countersunk screws.
(Or you could use countersink rivets with a flat head) I locked them with
double nuts AND locking fluid on the threads. I do not want anything to come
loose inside the axle and make funny noises.
21.
I chose a sealed bearing. Maybe it’s like wearing
both suspenders and a belt but at least I’m sure my brakes will never again have
contact with the axle oil. (Ruined my new brake shoes it did....) This bearing
is greased for life and the grease retainer in the hub will now function only
as a dust seal. You could probably do without both the grease seal as well as
the inner axle oil seal when using this bearing, but I haven’t tried this
myself.
22.
Here I’m pressing in the new bearing and the spacer
again using the same sockets and a couple of nuts to clear the grease seal
flange. Some newer seals do not have this flange.
23.
And here’s where it all should be in the end.
24.
If the brake backing plate was removed now is the
time to put it back. The tabs are then bent back to lock the nuts. NOTE! Take
care to check all tabs for cracks! Bending them back and forth will cause
cracks! One way to get around this problem is to simply make new ones, an
easier way is to use Nylok nuts or thread locking fluid. These options are good
as long as the nuts are not exposed to too much heat. A third way is to heat
the crack with an oxy/acetylene welder, melting together the metal again. Allow
the metal to cool off by itself as forcing this process can make the metal hard
and brittle. Karl tells me, in New Zealand, the locking washer is available in
the Transit parts book at some Ford dealerships. Enfords in NZ also sell them.
25.
After putting back the hub on the axle it’s time to
fasten the hub nut. The tabbed washer is one of those difficult to replace with
other solutions like in 24, but is very important, as the nut is all
that keeps the wheel from overtaking you on the road!
26.
The crude tool I made. The idea was right, but the
tool turned out to be too weak. It was good enough to tighten the nut again
though!
27.
See to it that the vent cap on the axle housing is
moving freely. As the axle warms up when driving (or from winter to summer), it
allows air from inside to vent out and the opposite when cooling down. If the
air can’t escape, it can press the oil past the seals. Another method of
venting the diff, is to run a straight through air line fitting tapped into the
diff vent hole with a rubber tube added on venting into a section of chassis or
the boot, along the lines of late model cars. This prevents oil mist collecting
on the outside of the housing.
28.
A small jump with new wheel cylinders and a little
paint. Almost ready for the road!
Hope
this will be of some use to anyone!
I
followed this method while rebuilding my rear axle and everything went
smoothly, (Steve (59-Z-MK2) Site Manager). Thanks Ulf
Disclaimer:
The advice and guidelines given in these articles are given in good faith.
The owners and managers of the Galeforce Zephyr site will take no
responsibility for any injuries or loss sustained while carrying out the
described tasks and procedures or any consequences arising. Please read
the Safety First
Article
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