Severe Vibration!

   I took Degsy out for a shake down down run before annual MOT. Shaking was what it did. As soon as I got aboove 20mph Degsy started shaking like mad. Enough to make it hard to hold the steering wheel and double vision inducing. Where had that fioble come from? As I slowed down the vibration reduced with speed. It was not a steering issue like unbalanced wheel. The vibration was definately emminating from the back of Degsy. I imediately thought the rear differential was giving up but it was not whining and the vibration built smoothly as I accerated. I wondered what it might be as I drove the short distance home. Time for a think.

   I mentioned the vibration to my neighbour who saw me looking at Degsy in a puzzled manner. "Universal Joint" said Roger. He told me how the check for play in the UJs (Univeral Joints). Sure enough play could be felt as I rolled the drive shaft backwards and forwards. It was not much but it was there.
 
   Right then, I quick look in the manual for an exploded view of the area in question, then on to Craddocks website for the items. It seemed simple enough, a UJ kit which came with circlips. Click HERE to see the items I also bought a set of replacement nuts and
bolts. £12 bought the lot.

   A few days later, whilst I waited for delivery I decided I would loosen the bolts to be ready for a quick install when the parts arrived. It was then I discovered one requires a special tool to get at the nuts. The forks of the UJ make it a tight fit for a standard socket so a slim version is required. Back to Craddocks, another purchase and another wait.
  

   A suitable Saturday rolled around and the weather was nice so I set about the job of replacing the rear UJ. Explanation of the replacement was pretty thin in the manual and on Youtube which, should have been a warning. Degsy has good ground clearance so having chocked the wheels as well as applying the handbrake and selecting first gear I was ready to get under Degsy. The slim 9/16 socket make good contact with nuts. The thought I having to extract a rounded nut in that position did not bare thinking about. As prescribed in the manual I undid the nuts securing the UJ at the forward end of the propshaft first. Getting at the rear UJ was a bit of a struggle so I jacked up degsy and removed the offside rear wheel. That made access much better. These nuts and bolts where harder to undo. Probably because of the resticted area to work in. However they came off without further ado. Once the propshaft was on the floor the fun and games really began.

  


   The manual says remove the circlips, one retaining each fork of the UJ. They were very grimey but they out fairly easily. Then use a drfit to press out each fork of the UJ. This is where things got tricky. Drift in the from and socket that fitted over the fork end ...check. Lump hammer...check. With a couple of preliminary taps I could see little movement. OK, usual procedure soak everything in 3 in 1 penetrating oil and have a brew. The next set of hammering made the UJ slide through the yoke. But now do you get the UJ out of the yoke. Its too big. More tea and more thnking. The manual was no help at all. Whilst fiddling with the new UJ I discovered the ends came off revealing a set of needle rollers bearings. The shaft within the bearing was shorter. AH HA! With some sublte hammering I pushed the bearing caps on each opposing end and the room was created for the cross piece to be removed. The caps with rollers were drifted out separately.

UJ Crosspiece with spigot parially in bearing cup.

  Now for the installation if the new UJ. I cleaned up the four bearing surfaces of the yoke and the circlip groove. I now knew the cross piece had to go in without the bearing caps. Luckily the needle rollers were held in place by thick grease. The first bearing cap slide in the yoke and managed get the spigot of the cross piece into the  bearing cap. The other end was not nearly so easy. The bearing cap would not go all the way in. I wrestled the cap back out to discover half the needle rollers had moved out of position and prevented the spigot seating. I lined the rollers up again offered the cap to the spigot, but the needle rollers moved again. Three more times I did this procedure until I was able to press the caps home without fouling the rollers. The second pair where just as bad but with newly learned dexterirty I only had to repeat the process twice. I tapped the caps so they appearred to be equi-destance from each set of circip grooves. The new circlip were set in place.The propshaft was ready to reinstalled

   Putting the propshaft back in place was a doddle. The UJ at the forward end fits onto studs protruding from the gearbox so is supported. The rear end of the propshaft slid into place against the input shaft for the diffential. Nuts and bolts secure the two together. Four nuts secure the forward end. That was the renewal complete.

   Whilst I had access to the differential a decided to check the oil level in the bevel box. After cleaning away 20 years of oil and dirt I was surprised at how easy the filler plug came out. I could see no oil. I put my finger in the hole.....nothing. I had 750ml of EP90 gear oil handy so I put as much as it would take...all of it in fact. I refitted the filler plug. It was no surprise to find the gears in the bevel box where quieter when I moved the wheel around. I refitted the road wheel with a generous smear of copper slip. The wheel nuts were very tough to get off. but went on much more easily. I dropped Degsy off the jack and prepared for a shake down drive around the block.

   I have to report it went very well. None of the violent vibration, the rear tramission was quiter. It is surprising what some oil will do. Next job is to get a grease gun and get some grease in to the greasing points. The lack of greasing was at partly the cause the the UJ failure. Having said that the UJs were new with the vehicle 30+ years ago. Time to book an MOT.