U-Joint Replacement

I replaced one of the UJs in my '85 XJ6 Sovereign about a year ago. It was one of the ones in the rear transverse half-shafts, but the same priciples apply to all (seven?!!) UJs downstream of the transmission.

I didn't need any special tools, but sometimes it is necessary to press out the ends of the driveshafts from the rear hub-carriers. There is a special tool to do this (quite expensive - the Jaguar Enthusiasts Club here in the UK sells them), but I'm sure something can be rigged up based on an ordinary puller or something. If you're just doing the main prop-shaft (not the half-shafts) then you wont need this tool anyway. Mine came apart with just hand pressure in any case. THE SYMPTOMS: I posted to jag-lovers on this topic a few weeks ago:- I began to notice a nasty "CLACK" noise that would sometimes come from the rear suspension area on pulling away and sometimes also (less often) on decelaration. It very soon got worse and began to sometimes give a whole sequence of them "CLACK-CLACK-CLACK_CLACK!" which seemed to mostly occur on right-hand turns when accelerating. THE DIAGNOSIS: A buggered UJ in one of the rear drive-shafts. (Thanks to all who helped with this especially Jullian Mullaney and Johann Orn Hedinson). I jacked the rear of the car up and had a feel around but not much play was evident. However, there was some squeaking and groaning from the shaft as I rotated it and the torque required seemed to vary rather a lot in the course of one rotation. With the hemi-spherical sheet steel joint covers loosened and slid clear I tried again and noticed a bright jagged edge where a piece of one of the inboard needle roller bearing cups had broken away! - definitely a UJ in it's death throes! THE DESIGN: A brief bit of background The Jag independent rear suspension uses the driveshaft as an upper wishbone. The rear brake disc is at it's inner end. Two dampers and springs go on either side to give it room. It's a brilliant design which is very compact and cuts out the weight of both a brake disc AND an upper wishbone from the unsprung mass. However, it DOES mean that not only does the drive torque get transmitted through the UJs in the drive shaft but so does the braking torque AND the weight of the car. That doesn't matter though 'cause they've got to be nice and beefy anyway. I don't think they fail very often (mine's got about 105000 on it). THE TREATMENT: Drive-shaft removed, new joint put in, then replaced. I put the rear of the car up on axle stands and removed the rear wheel. I then removed the big stub-axle nut on the end of the drive shaft which holds it in the matching spline in the rear hub. A split pin has to be removed first, mine was corroded into it's hole and had to come out in pieces. The splined end of the driveshaft needs to be pressed inwards out of the hub to allow the aluminium hub carrier casting to swing outwards pivoting on the lower wishbone. In practice I found that the shaft was loose in the splines already at this stage so it could be done by hand and I didn't get to have any fun with the makeshift puller that I'd rigged up to press it out! Remove the grease nipple from underneath the hub carrier before you swing it clear otherwise you might crush it or break it off. Next a shock absorber/spring unit needs to be detached from the bottom wishbone and swung clear so that you've got enough room to get the shaft out. Actually, I found it convenient to detach both units. The pin on which the lower end of the shocks sit is a sliding fit in both the wishbone and the shocks themselves. Mine was seized in the rear shock though, - needed a bit of penetrating oil and light tapping. Note that with the rear of the car jacked up the shock/spring units are fully extended so there's no need for spring compressors or anything like that. The next job is to undo the four 7/16 UNF nuts that hold the inner flange of the driveshaft to the brake disc. I found that the easiest way to get a good grip on these was with a socket and an extra long extension going in from the wheel arch over the top of the drive shaft. You can rotate the wheel to bring each nut in turn to the top and then use the handbrake to lock it. You will need to remove the grease nipple on the inner UJ spider first otherwise you can't get the socket on one of the nuts. Alternatively you could use a ring spanner from underneath the car - but apart from greater leverage, the socket has the advantage that you can use a torque wrench when you do them back up again. You can now withdraw the drive-shaft, collecting the shims that are trapped between the inner flange and the brake disc to set the camber ...there were four on mine, some a bit rusty so I cleaned them up with wire wool To remove the offending UJ you first reomove all four circlips and then tap one of the bearing cups inwards until the opposite one is 3/4 of the way out. Then you grab it in the vice and twist/pull the driveshaft off it. Then you tap the end of the spider until the first cup is most of the way out and then remove that too. You repeat this process with other two bearings. The bearings that had failed were the ones in the main shaft section of the inner joint. They were completely annihilated! - on the worst one the unsuppported outer skirt had begun to break up and only brown, rounded, broken-off fragments of needle roller remained. It looked like quite a lot of roller fragments had actually been spat out, the grease seal being in tatters. On both bearings the spider was badly indented. Before dis-assembly the bad bearings felt a lot stiffer that the others rather than having any discernible play. The replacement UJs come with a complete new spider, four new bearing cups with all the rollers, and new circlips and a grease-nipple. They are quite cheap, I got mine for 17 pounds Sterling from my local Jaguar garage although you can get them cheaper by mail order. I'm glad I read Micheal Neal's notes on UJ fitting (on the web-page) before driving the new bearings in - strongly recommended! Basically, the idea is that you always have the new spider partially inserted into each bearing as you tap it in, that way the rollers are held in position and can't fall out in a jumble making you start again. Follow Micheal's instructions and it is easy. I cleaned up the bores in shaft and flange with wire wool before fitting to help minimise the force necessary to drive the new bearing in. With new circlips in you're ready re-fit. (Don't put the new grease nipple in at this stage like I did because you'll have to remove it again to get access to one of the shaft/disc nuts :~) The only other thing I did was to drill out the split pin hole to remove the last corroded remains of the old pin. Replacement is the reverse of removal (I can't believe I said that! - do I have to pay a royalty to Haynes?) I used new 7/16 UNF lock-nuts and a new split pin. I also wire -brushed all the threads and cleaned up the splines before smearing on a little anti-seize paste (paranoid?, - moi?) THE RESULTS A nice smooth evenly-turning drive shaft and no more nasty noises from the rear end! Hoorah! It was a very cheap job (who started the "expensive-to-maintain" myth?) and not a very difficult one:- perfectly feasible with no covered garage and no pneumatic tools. kind regards,

Just remember that all the U Joints in your Jag will also fit a Chev. The joint for the prop shaft is a Spicer no 5-153X and can be bought at any parts house,Pep Boys, Autozone, Advance Auto, etc, etc.. If memory serves me the 1/2 shaft joint is a 160, also can be bought at Autozone, you just have to get a person to help you who has the brains to look it up. To change them is no different than changing a Chev, now getting the shafts out is another story.

Once the drive shaft has been removed from the car each joint can be removed with two sockets, WD-40 and a large C-clamp (you might need a snap ring remover). The outside diameter of the first socket should be about the size of the diameter of the caps of the u joint (if not a hair smaller). the other socket should be have an INSIDE diameter larger than outside diameter of the cap. the object is to use one socket to push the U joint out far enough to take the caps off and remove it. The smaller socket does the pushing and the larger socket braces the other side of the C clamp opposite the smaller one without getting in the way of the movement of the U joint.

With this being said, place both sockets on opposite sides of the U-joint and the C-clamp on the sockets. Use plenty of WD-40 on the joints to make it move easier. Tighten the c-clamp so that the smaller socket pushes the U joint and it starts to slide toward the larger socket and into the inside of it. At the first opportunity, you take the caps off the U joint. Once all the caps are removed the U joint will come out of the center.

When installing, make sure that all the surfaces where the caps will be sitting are VERY clean and rust free. Some people will not recommend this, but I use a very fine emory cloth to remove the debris. If you change the integrity of the metal, you have ruined the surface and the U joint will fail, so only remove the rust. You can use the C- clamp method to install the caps, always checking the alignment of the cap as it goes into the yoke and the spider as it slides into cap.

Now...this is very important. Please, please, please mark each side of every part of the drive shaft assembly that you remove (i.e. each yoke on a U joint and yoke to pinion flange) with something (white out). It has to go in with the exact alignment that it came out. It is very important to eliminate the possibility of drive shaft vibration.

The last tip.... put the C clamp in the vice and the shaft across the bench.

Jeff XJSC