U-Joint issues, early Lotus Seven S2

[Gearbox]

When the simple becomes a PITA. Not one of my favorite jobs, but never really had a problem with U Joints. Working on a 1962 Lotus Super Seven, Anglia 105e 977 gearbox and Standard 10 rear. I assume everything is original to the car including the prop shaft.

 

Restored my drive shaft (prop shaft), got a new set of U joints from Bean, and pressed the old ones out. And of course, they were a nasty mess, so I tossed them. Then I noticed that the new U joints were too wide to allow the circlips on both sides to seat. Ok, pressed them out and started to measure. The U joints were the standard 0.937" cap diameters and outside cap to cap compressed was 2.41". But when I measured the dimension of the yokes, inside to inside between the circlips, I get 2.31", or about a full 0.100" difference. I measured all 4 yokes, and they all measure the same give or take a few thou.

 

My first reaction was that I got the wrong U joints, but after talking with DB and searching the world for a U joint that would be close, they aren't any. Now I'm thinking that the yoke got squeezed together somehow when I removed the old joints, but it doesn't make sense as the measurement is the same 2.31" from the base of the yoke to the top. You would think the top would have squeezed in more if it distorted. Plus these yokes are cast iron, I would think if you moved them by 0.100" they would crack or something.

 

So what am I missing here? I'm thinking I may have two options, either spreading the yoke or possibly milling off 0.050" from each tips of the spyders. I'm not crazy about spreading the yoke as that may crack the yoke or at minimum mis-align both sides. The milling would allow the caps to sit lower and it looks like the needle bearings will still have enough on the spyder for full contact, but the grease seals would be a bit squished. None of these are in any way close to optimum, but at a loss on what to do. Any ideas, or am I missing the obvious? Thanks Allan

Edited January 30, 2015 by Gearbox

[DeanG]

I had a similar issue with my series 1. I had mistakenly assumed that the correct U-joint was from a sprite. A local drive shaft shop was able to find a replacement.

 

I see 3 from http://www.machineservice.com/products/universal-joints/universal-joint-dimensions-parts-catalog/

 

50701000XMS OSR 0.938 2.411 61-B OR 1100 50701000

5-101XMS OSR 0.938 2.411 1100 5-101X, 1-0300, 340, CP101X

5-111XMS OSR 0.938 2.411 1100 5-111X, 1-0300, 341, CP111X, 5-101X, HS194, GU500, 114-581

 

1 from http://www.drive-lines.com/ujs/bpujs.php

 

It seems unlikely that all 4 were squeezed the same amount. Good luck.

Edited January 29, 2015 by DeanG

[Gearbox]

Hi Dean;

 

Those were exactly what I found, anytime they had a 0.9370 or 0.9380 dia. cap, it immediately goes to 2.411" cap to cap. Seat one side with the circlip, and the opposite side cap blocks the circlip groove. The 0.970" by 2.411" is the standard U joint for the Anglia and everybody tells me that should be the correct joint, so I am still confused.

 

As for the second source. I see that they have a 0.938 by 2.280". which is 1 thou larger in cap diameter, but too short by 30 thou side to side. I called them up and they told me that the 30 thou play was too much, and I brought up the possibility of shims, and they dissuaded me from that. Next step is to make custom joints, but would really like to know what drive shaft I have and was it a Lotus part.

[Paul Hill]

Been down that road...the LOG event at Gettysburg the rear u/j decided to give up almost as soon as we dropped it out of the trailer Thursday, took til Saturday to find the right joint.

 

All part of the fun of Lotus ownership!

[Gearbox]

Just to wrap this thread up, I am still unable to find the correct U joint. Bean sent me a couple of standard joints, and again they were .100" too wide side to side. So without any other options I decided to mill down each side of the cross by 0.050". The roller bearings still had enough race surface on the cross and it seems to work. Really hate jury rigging like this, but had no other option. Hopefully one day someone will tell me what I missed, but for the life of me, I have no clue what it could be.