Lotus Elan

Rear bearing housing removal (having problem CV's installed)

PostPost by: stugilmour » Thu Aug 30, 2012 4:08 am

I have removed the rear bearing housing and shock tower from the left side of the car. Having problems with the right side.

I have removed the wheel hub, spring and outside wishbone bolts. I can't get the assembly to release from the bolts in the RD supplied CV's. The nuts are off and the brake rotor is free.

Do I have it right that the CV should just pull free of the outboard drive shaft with no sweat? The bolts in the CV that attach to the three spider arms on the outboard drive shaft and brake rotor are pretty long to get free of the whole assembly. With no Rotoflex to remove there is not a lot of play to shove the CV shaft inward in order to get everything out. Looking over the stock setup in the Parts Book, the CV setup is a bit different as the bolts are attached to the CV and are not removable. Thinking I may have to split the CV to get the bearing housing on the bench to see what is going on, but thought best to ask first.

The right side looks like it has spacers on the outboard drive shaft so that the inboard CV shaft lengths are equal, but otherwise the same as left side. I didn't seem to have a problem with the left side, but this right side is just not freeing up.

Any suggestions welcome. Was getting tired, so dropped the tools this evening before I wrecked something.
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PostPost by: UAB807F » Thu Aug 30, 2012 5:09 am

I think (note "think" ) that the last time I removed my CV setup I took off the lower A-frame completely from the carrier & chassis and then undid the CV at the inboard end. I was doing a complete strip down so removed the damper as well so the whole unit (spring, damper, hub carrier,disc) came away from the car.

My set up is the Sue Miller one but no doubt very similar to yours. The design has fixed studs in the CV adapter plates and is also very tight to either fit or remove. I've fitted it twice, removed it once and never had to do anything to the CVs themselves, they're still as they came from Sue.

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PostPost by: AussieJohn » Thu Aug 30, 2012 6:22 am

When you do get it apart it is probably that the 3 eared bolt holes on the original half shafts are not very accurate, I had a mate machine about .008" off the shoulders on the studs fitted to the cv adaptors, much better to remove and assemble.
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PostPost by: stugilmour » Thu Aug 30, 2012 4:28 pm

Thanks guys, very helpful. Sounds like I am on the right track but the fit to the outboard bearing shaft is just tighter than expected.

John, I had forgotten how tight the CV captive studs were to the bearing shaft spider. That is probably what is hanging up. I now recall I had to relieve the holes on the three armed spider to fit the CV's originally; I imagine they are off enough that removal is a bit of an issue. To prevent damaging it I guess I may have to do like Brian and remove the CV shafts to get some working room on the bench.

When you mention machining the shoulder of the stud, is this to slightly reduce stud length to give more clearance? I'm not quite getting what you mean. My studs to the bearing shaft spider are countersunk into the outer CV flange and can be backed up with a 1/4" socket head to get the Nyloc nuts off. However, the countersunk head edge is slightly under the CV housing, so the stud cannot be moved back in it's hole. The whole outer CV, CV shaft, and inner CV have to be compressed / pushed back to gain clearance behind the spider. Figured bearing carrier removal would be easier with the outer wishbone bolts removed, but I just managed to get the left side off with the wishbone still attached. Right side may be different though as I think I see spacers behind the brake rotor.

Brian, not sure but I think the critical difference between the RD CV kit and the Sue Miller design is the shafts into the diff. I understand the Sue Miller design uses the stock three armed spider diff output shafts and the inner CV attaches with studs to the spider in the same way as my outboard CV? The RD kit comes complete with replacement splined diff output shafts with a round flange face looking out (to replace the three armed spider on the diff output shaft). This flange appears to connect directly to the CV housing with several socket head screws. I believe this is the CV I split during the original install, but can't remember for sure. I will take a close look and report back.

I now recall that one of the CV's was miss-assembled and had to be clocked for it all to fit, but details are vague. I remember discussing the issue with Ray and he had never seen this error before and was pretty baffled with my question/problem. :)

Sunny day so will give it another go. Thanks for the help.
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PostPost by: UAB807F » Thu Aug 30, 2012 4:45 pm

Stu,

Your description of my CV kit is right, both ends are Al flanges with studs attached and just bolt to the standard diff output shaft & outer hub shaft in the same way the rotoflex do.

It sounds like the RD kit is quite a bit different and I'd guess the only way to do it is to split the joint as you propose, certainly I can't hink of another way at the moment. Presumably the custom diff output shafts are tougher than OEM lotus and it's designed for more power ?

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PostPost by: AussieJohn » Thu Aug 30, 2012 5:18 pm

Hi Stu, no, I didn't shorten the studs. Do the studs have a shoulder of unthreaded section where it goes through the spider and disc? this is where we reduced the diameter down to the outer threaded diameter [The same as enlarging the holes in the spider] cheers, John.
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PostPost by: stugilmour » Fri Aug 31, 2012 2:34 am

UAB807F wrote:Stu,

Your description of my CV kit is right, both ends are Al flanges with studs attached and just bolt to the standard diff output shaft & outer hub shaft in the same way the rotoflex do.

It sounds like the RD kit is quite a bit different and I'd guess the only way to do it is to split the joint as you propose, certainly I can't think of another way at the moment. Presumably the custom diff output shafts are tougher than OEM lotus and it's designed for more power ?

Brian


Thanks for clarification Brian. I think the RD shafts would at least be equivalent to the later Lotus ones. My stock ones were presumably high strength based in my VIN, but they looked slightly twisted when I removed them.

I ended up splitting both CV's, but for different reasons. While trying to jerk the bearing carrier loose, the flange face on the diff output shaft detached from the shaft. :shock: Turns out it is a spline looking outward and retained by a circlip inside the CV housing. With the shaft separated I was able to remove the whole shebang and take a closer look.

I split the outer CV housing and worked the counter sunk screws out of the spider individually. 20/20 hindsight I should have split this one first. I have re-assembled it and will relieve the spider holes a bit more so that it doesn't jam up.

John wrote:Hi Stu, no, I didn't shorten the studs. Do the studs have a shoulder of unthreaded section where it goes through the spider and disc? this is where we reduced the diameter down to the outer threaded diameter [The same as enlarging the holes in the spider] cheers, John.


Thanks John, I get it now. Yes, my screws that form the stud to connect to the bearing shaft have a smooth portion as well. Unfortunately it is the threaded portion that is hanging up, so a little more relief in the spider holes should fix me up.

A bit of a correction. Must have been tired when I looked at the spider. Both sides are the same, and where I thought I saw a spacer I was just seeing the spider.

With everything out I can fix both upper spring abutment plates, which are worn to round and make it difficult to tighten the shock top bolt. Brake pads and rotors look good, so assuming the slight brake pulsing was caused by the outside bearing failure. One of the bearings was missing half it's balls! :shock: I am going to get the new bearings pressed into place at a shop as I suspect my previous amateur attempt damaged the bearing with excessive side loads. Bearings should be here next week, so hopefully all back together shortly.
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PostPost by: AussieJohn » Fri Aug 31, 2012 2:19 pm

Hi STU, it's worth checking the spider ears on the half shaft to see whether they are true; if you know someone with a lathe get both sides of each ears trued. I didn't do this and had to shim the disc to correct runout. cheers, John.
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PostPost by: stugilmour » Sat Sep 01, 2012 3:24 am

I was wondering about that John. I got the parts today and dropped everything off with the mechanic to get the bearings installed. Long weekend / bank holiday for us here, but will ask Malcolm about what you suggest next week. Pretty sure he doesn't have a lathe, but will know a guy. Bit of a pain as will take a bit longer to get things back, but you are probably right to tend to this issue. The originals are 'machined for rubber', so checking them is probably the way to go. Brain Buckland certainly recommends doing it.

thx
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