john's FSJ pages are devoted to the J-series Wagoneers, Cherokees and J trucks produced from 1963 until 1991.

Date sent:         21 Apr 97 16:21:46 EDT
From:  Michael Baxter 

<74172.1164@CompuServe.COM>
Subject:           Spring maint...time to grease U-joints

I spent an exciting Saturday night doing Spring preventative maint. on the
Wag. (read...no social life).

 Just a reminder that it's time to get out your trusty grease gun and
grease-up the U-joints. Having never submerged my U-Joints in water (there's
not a whole bunch of deep water crossings around here) and making sure they
get greased every year are the sole reason why I still have all my factory
joints. Properly set-up quality (Spicer) U-Joints should last you...or say
165,000 miles at least (that's the mileage on the Wag.).

 As a review on the proper way to grease them: Use Extreme Pressure (EP)
grease that isn't too thick. Don't use lithium based grease unless you've
changed the joints and used it initially. Not supposed to mix greases and
Jeep
used EP grease at the factory although, I've found that any grease is better
than no grease.

 A good grease gun is required and you'll need a "needle" adapter for the
end
of the hose in addition to the standard zirk adapter. The needle adapter
will
attach to the end of the hose and they look like an oversized needle. You
should be able to find one at a automotive tools or a good size auto parts
store.

 You can use the needle adapter to grease all the fittings if you don't want
to crawl out and swap them when you run out of standard zirk fittings. But,
a
manual grease gun with a needle adapter requires either ingenuity or three
hands to operate. One hand to hold the needle tight in the hole, one to hold
the grease gun and one to pump the handle. However, I have done it with a
manual gun and only two hands in the past and if I can figure-out how; you
can
too.

 Luckily, I now have a air driven grease gun as well as a good manual one
and
I use the air gun for the hard to reach fittings (read the Double Cardan
joint).

 I start at the back and work my way up front. You can start anywhere you
want. My garage floor is flat and I can roll the Jeeps along to expose the
zirks/cups but, you may have to jack yours up so you can turn the drive
train.
Jack both ends if it's Full-Time FWD.

 Take a rag or two along when you dive under there. If you can gain access
(you can't always), clean each zirk/cup fitting off with the rag before you
grease the fitting.

 On the rear drive line, you'll have three fittings to grease (unless you
have
a LWB truck with an intermediate shaft...in that case more fittings). One
zirk
each screwed into one of the saddles on the cross of each U-Joint. Just pump
the grease gun until you hear a "pop" noise or you see grease just starting
to
emerge from the cups. The "pop" is the air being displaced by grease.

 The third zirk on the rear shaft is on the slip joint. Connect the grease
gun, and then pump while watching in the saddle of the "U" at the very end
of
the tube. Essentially looking through the U-Joint at the beginning of the
driveline. When you see grease start to come out of the vent/overflow hole
at
end of the tube stop pumping. Then stick your finger up in there and plug up
the hole (oops...three hands with a manual gun again) and continue pumping
until you see grease start to emerge around the splines at the slip joint.

 Do the very front U-Joint and the front drive shaft's slip joint the same
way.

 Now the Double Cardan: This is the fun part. First, if you don't know what
a
Double Cardan cross is just crawl under there and find the single driveline
joint that looks totally different from the rest. It's a constant velocity
joint and it is essentially two U-Joints in one.

 Don't skimp on this joint! Especially if you have a Borg-Warner Q-T. If you
ever loose that joint at highway speeds, it'll take your transmissions case
with it. You'll find yourself at the junk yard asking for a new case. The
junk
yard owner will know why your there and charge accordingly. He's seen a lot
more like you in the past.

 The Double Cardan has three grease fittings. At least one of them will
probably be the cup style. The cup style fittings are "cup" shaped and the
have the steel check ball right at the bottom of the cup. On my Cherokee,
all
three are the cup style. I've seen others in the past that had regular zirks
on the crosses and the only cup was the one in the middle.

 These three fittings can be hard to find (especially on the BW Q-T FSJs).
It's tight around the joint. They get covered with grease and dirt and it
always takes me a little searching to find them. A good light is a
necessity.

 Grease the fitting on the crosses just like the other U-Joints. Until you
hear a "pop" or start to see grease coming out of the cups at the end of the
crosses. I should've better defined "grease coming out of the cups" before.
I'm taking about the cups at the end of the crosses in the U-Joints that
contain the needle bearings and not the cup shaped zirk fittings.

 The rear most cross in the Double Cardan is the hardest fitting to find,
clean and grease. On my '79s (BW Q-Ts), I can usually get it using the
needle
while it is at a 45-60 degree angle from straight down. But the zirk/cup
pointing straight down is not out of the question though. You may be able to
get at it through one of the holes in the cross member (which are intended
for
this very purpose).

 Right in the center between the crosses, there are two holes 180 degrees
apart. At the bottom of one of those holes will be a cup type fitting. You
will (unless you are an Ape) have to position the fitting so it points
straight down and then push the needle & hose through one of the holes in
the
cross member. You'll also need to get your head in just the right location
to
be able to see the fitting while your greasing (I believe you'll be looking
through another hole in the cross member). You have to be able to see the
cup
to be able to tell if you have the needle seated properly. If it's not
seated
just so, you'll pump a bunch of grease into the middle of the joint and it's
hard to clean it out of there. Pump until you see grease emerging elsewhere
in
the joint (not around the cup). You are all done.

 The real reason I did wrote this is because i want someone to console with.
I
hate doing this chore every year. I get a little better every year at doing
it
and it pays off in the long run. So, hurry-up and do it so you don't all
have
to live vicariously through me and my miserable experiences.

 BTW, I learned the proper greasing technique from an old guy at my favorite
tranny shop a few years back. Mainly the part about plugging the hole with
your finger so you can force grease up to the spline.

 -- Michael Baxter, 74172.1164@Compuserve.com
 http://ourworld.compuserve.com/homepages/MBaxter
 From Reno, NV USA on 21-Apr-1997 at 13:00:54 PDT