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Propshaft Repair – How to Replace a Universal Joint


Warning! In this video I will be saying, nipple, flange
and I will tell you to grip your shaft and grease your nipple! But it’s OK, it’s Educational. Hi, Matt here from educational mechanics. Today were going to show you how to change a universal joint on a prop shaft. Universal joints articulate through a Hooke joint and use needle roller bearings and cups, and they are greased through a nipple. They are quite often over looked with lack of grease and with normal wear and tear, especially
in on off road vehicles, they fall victim to excessive wear and premature failure. If the Universal Joint comes apart when you’re driving it can cause severe damage to the vehicle
and injury to the people inside. So it’s important to keep on top of your prop shaft maintenance. You can easily check for wear by hand, as you can see with this one we’ve got in a vice and a firm grip on the shaft, pulling it in all directions. If you find any wear in the prop shaft universal joints, they do need to be replaced. Before you start, make sure you’ve got the right UJ kit for the job. Your parts supplier should be able to give you the right part with just giving him your registration number, as all vehicles are now on a database. But it’s always worth checking that you have got the right one before getting your hands dirty. We’ve checked our bearing part number, so we’re sure we’ve got the right one. So, Remove all the circlips that are there to retain the bearing cups. Hit the prop shaft with a mallet or soft hammer. The Hooke joint will act as a kind of slide hammer and this should shock the first cup out, do this until there is enough of the cup showing to clamp in a vice. Clamp the cup in a vice and work it out by
turning backwards and forwards. Using a mandrel, which is a special tool made for the job, press the Hooke joint through the yoke, again press it far enough so the
cup can be gripped in a vice. If you don’t have the right mandrels, you can use a couple of sockets, one small enough to press the
cup through and another one on the other side big enough for the pressed out cup to go through. Holding the mandrels can be a bit fiddly, so you might want to get someone with really hairy arms to give you a hand. Clamp the second cup in a vice and work it out. Once the cup is out, remove the Hooke
joint from the yoke of the prop shaft. and try not to drop the needle rollers all over the floor. Repeat the same sequence using the vice and the mandrels or sockets, and remove the bearing cups from the flange Remove the Hooke joint
from the flange and put it to one side. Don’t throw it away just yet. Have a look at the yoke holes where the bearing cups sit. Give them a bit of a clean-up and check for any damage. If there are any slight burrs, you can buff them out with a bit of abrasive paper. Do this for the yoke holes in the prop shaft and the flange. Take the new Hooke joint out of the packet, along with the new circlips and if there is a grease nipple fitted, take it out and put it somewhere safe. Have a look at each cup and its needle roller bearings, making sure they are all there and are new and complete. If you put a little bit of grease in the cups
over the needle rollers, it’ll help to keep them in place when you’re rebuilding the joint in the prop later, and prevent you from searching for them when they all drop out. Now, take the nicely greased new joint to where you’re rebuilding the propshaft and remove all the end caps. Put an end cap into the bottom of the yoke, then insert the Hooke joint firstly through
the top hole, then sliding it carefully into
the bottom cup. Make sure that you’ve got the grease nipple hole on the prop shaft side of the joint facing away from the flange. If you put it on the flange side, you won’t
be able to get a grease gun on the nipple
to carry out your maintenance. Carefully fit the top cap, making sure the needle rollers sit nicely over the shaft of the joint. Put the assembled yoke into a vice fitted
with soft jaws, and slowly squeeze it together, checking the joint is going nicely into the cups and needle rollers as you go, by wiggling it. If it won’t wiggle, stop and check the position of the roller bearings. When you’ve pressed both cups in as far as they can go into the yoke, take it out of the vice. Using a mandrel or socket use the vice to press the end cap in, press it bit by bit, and keep checking until the circlip groove is fully visible. Put the flange in the vice and fit a circlip, if you put one finger on the circlip its less likely to ping off and either you in the eye, or make you get on your hands and knees and spend 10 minutes looking for it. Again for the other side, using a mandrel or socket use the vice to press the end cap in, press it bit by bit and keep checking until the circlip groove is fully visible. Put the flange in the vice and fit a circlip. Now, put the prop shaft into the vice, with the yoke holes top and bottom. Put an end cap into the bottom of the yoke, then insert the Hooke joint firstly through the top hole, then sliding it carefully into the bottom cup. Carefully fit the top cap, making sure the needle rollers sit nicely over the shaft
of the joint. Put the assembled yoke into a vice fitted
with soft jaws, and slowly squeeze it together, checking the joint is going nicely into the
cups and needle rollers as you go, by wiggling it. If it will not wiggle, stop and check
the position of the roller bearings. When you’ve pressed both cups in as far
as they can go into the yoke, take it out of the vice. Using a mandrel or socket use the vice to press the end cap in. press it bit by bit and keep checking until the circlip groove is fully visible Put the flange in the vice
and fit a circlip, remember, putting one finger on the circlip. Again for the other side, using a mandrel or socket use the vice to press the end cap in, press it bit by bit and keep checking until the circlip groove is fully visible. Then put the flange in the vice and fit a circlip. Fit the grease nipple to the joint and with a grease gun, pump in grease until it is seen coming from the cup seals. Wipe off any excess and revel in your own glory, as you have successfully replaced a
prop shaft universal joint, and you’ve saved yourself a bit of money and learnt something new. Thanks for watching.

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