Land Rover Discovery Rotoflex to U-joint Driveshaft 
    Conversion

  by Bill Gill
  
 
  

   

After I lifted my 1996 Discovery 
    about 2" with OME suspension, my rotoflex couplers started failing. I replaced 
    the rotoflex driveshaft with a stock rear driveshaft and stock 4-bolt pinion 
    flange from a 1998 Discovery. 
  
 To convert from rotoflex to u-joint, 
    you not only need a u-jointed shaft, you also need the proper 4-bolt pinion 
    flange (the rotoflex utilizes a 3-bolt pinion flange). Here are the two different 
    flanges:  
  
  
  
 Here's a comparison of the loosely 
    assembled pinion flange ends of the two different driveshafts - you can see 
    that the 4-bolt pinion flange (foreground) needs a spacer ring (holding it 
    in my fingers) to match the depth of the 3-bolt pinion flange. The spacer 
    ring is available from several vendors, I picked mine up from Atlantic British 
    for $10. 
  
  
  
 Remove the six 19mm nuts and remove 
    the rotoflex coupling. You have to compress the driveshaft as much as possible 
    to free up enough space to get the rotoflex to drop out. Try using a screwdriver 
    or pry bar as a lever to compress the shaft. 
  
  
  
 You'll probably find that your 
    centralizing peg is stuck in place. There is a special Land Rover tool (really 
    just a puller) to remove a stuck peg. You should be able to think of a creative 
    way to pull your peg off if it's stuck. Luckily, mine was loose. 
  
  
  
 Here's a pic with the peg removed. 
    The pinion nut is 24mm. 
  
  
  
 There is also a Land Rover special 
    tool to remove the pinion nut - the problem is that as you torque the nut, 
    you are in effect torquing the pinion, which engages the differential and 
    axles. Jacking the rear end up to create a little working room further compounds 
    the problem (rear wheels just spin). The special Rover tool secures the flange 
    as you torque the nut. I didn't have the tool, and my pinion nut was stuck 
    on there tight. I was able to get it off by securing a piece of steel between 
    the flange and garage floor, and I also used a little creative wheel chocking 
    - I jacked the back end up about 3" and jammed pieces of 4x4 under the rear 
    wheels. 
  
  
  
 Here's a pic with the flange removed. 
    You can see my original pinion oil seal and the pinion itself. I've put the 
    spacer ring on the pinion in this photo: 
  
  
  
 Unfortunately, I broke the pinion 
    oil seal during this project, and I had to fit a new seal. Here's a pic with 
    the seal removed. You can see the bearings - Timken #M88046: 
  
  
  
 …the new seal installed ($10 from 
    Nathan at Discount Rovers): 
  
  
  
 Here's the 4-bolt flange installed 
    and a new pinion nut (M16 x 2.0 nylock from Copper State Nut & Bolt, $0.50): 
    
  
  
  
 Here's the finished project - I 
    used four 1.25" x 3/8" grade-8 bolts with nylock nuts  
  
  
  
 Vibe-free up to 85mph, which is 
    about as fast as I ever want to go in the White Whale…