Intermediate shaft run out

[IainP]

I acquired a Sprint last year. I’ve just stripped the rear suspension, bushes a bit worn,and have taken the time to go through all the components. One intermediate shaft has approx 1.5mm of concentricity. Having read Buckland, he suggests checking between lathe centres….hence I know the concentricity. What he doesn’t say is how to fix it? Can I just machine the shaft to true it up? This side of the vehicle did suffer from vibration issues, which I thought was the wheel, but is possibly the shaft?
Many thanks

[MACCA.GLM]

Hi

If you have a lathe you need a catch plate and centres fitted instead of a chuck with a suitable drive between the plate and the shaft
As it’s as you say about 1 1/2 mm it should clean up ok.

If you haven’t got a lathe a good engineering company can do that for you.

Other alternative is to put some solid drives or uni shafts which do away with all of the rotoflexes and and intermediate shafts.I did that and a worthwhile upgrade in my view
As no worries about flailing rotaflexes which can cause serious damage to the body and chassis if not checked regularly

Regards
G

[512BB]

Welcome to the board Iain. Vibration on Elans can be caused by many things and is certainly very irritating, but I am not sure that taking 1.5mm off the inter shaft is the way to go. I have never cut one in half to see how thick the tube is, but 1.5mm is quite a chunk of metal to remove. I think you would be better off finding one that was true and I have several that you could try.

Whilst you have the rear suspension broken down, I would put the outer drive shaft in the lathe to see what the 3 ears are like, as this is a known hotspot for vibration if they are not running true.

Should you ever get the opportunity to remove the propshaft, be sure to get that properly balanced, even if it has weights already on it. I had a propshaft fully refurbed by a firm, inc. new u/js. The difference was like night and day, and it appeared to have been previously balanced.

Good luck with it.

Leslie

[englishmaninwales]

+1 on Leslie’s comment above on getting the propshaft refurbished and balanced - as he says, the difference is like night and day!
Malcolm

[IainP]

Very helpful comments gents, the prop shaft will be out soon, diffs on the bench now. The outer drive shaft will hopefully be out tomorrow, the bearing is rumbling so that needs sorting. Any recommendations for bearing suppliers? I always try to use genuine Timken on my Tr3.
Iain

[snowyelan]

The centers aren't necessarily concentric to the axis of rotation. If you have the tools, I recommend you check that the 3 (per end) rotoflex mount holes are equidistant from the centers first. I'd avoid turning any material off the tube. One for strength reasons, but also because you will now have created an imbalance due to tube wall thickness variation.

[IainP]

I’ll do that Scott.
Iain

[RichardHawkins]

Ian,

From your posts you appear to have a lathe. If so you need to check everything. What Scot said is precisely what I found. At risk of upsetting someone, a lot of lotus engineering was poor, add to that, accident damage and previous owners not being able to afford correct service and repair.

In my case, when I took the differential apart there was very little oil and quite a lot of broken pieces of metal. The three eared flanges/spiders that attach to the rotaflex couplings were all out of true in some way or other. I had more or less decided to adapt to constant velocity joints, and the damage I found made my mind up.

Having a tendency to technical arrogance I thought I could make my own CV driveshaft adaptors. I have, but the amount of work makes me think it was a mistake. On the plus side I was able to compensate for the concentricity errors that I found on the three eared spiders.

Hope this helps,

Richard Hawkins

[IainP]

Hi Richard, the sum of the comments above reinforce my original thinking, “ whilst it’s apart check everything” which is what I will do. I’ve been around old cars for 40 plus years and am too aware that fixing one bit and not checking everything else is only a short term gain.
Many thanks for all the comments I’ll report back and clearly seek more advice, as a newbie to Lotus ownership
Iain

[512BB]

Your Sprint Iain, should have an Issue 18 ali housing which uses one narrow and one wide bearing. My bearings of choice are RHP and SKF. I don't think Timken make bearings for that application and RHP are very difficult to find now, so its SKF, which are top quality, so long as they are not counterfeit. 000's of bearing suppliers on line, inc Simply Bearings, and probably someone near where you are locally.

Post up some pictures of your car in the INTRODUCE YOURSELF SECTION, and tell us about it. Everyone wants to know

Leslie

[IainP]

Hi Leslie
Yes it has issue 18 bearing housings. I’ll go with SKF from a local bearing factors.
Iain

[Andy8421]

Iain,

At the risk of igniting an old controversy, I wouldn't bother trying to true up the shafts, I would put them in the bin and treat myself to a couple of CV driveshafts. Given the price of new Rotoflex couplings, the step up in cost to CVs isn't terrible.

If you choose to stay with Rotoflex, there is every chance the couplings are out of true by more than 1.5mm.

Good luck,

Andy.

[IainP]

[smo17003]

Iain,

Not sure how far you are with taking it apart but be very careful when removing the rear hubs. Although they might appear quite substantial they can easily distort if not removed carefully, and with the correct tools. There's plenty of advice on here with good suggestions, and things you shouldn't do. Good luck.

This topic has the bearing numbers viewtopic.php?f=42&t=52640&start=15

Mike

[IainP]

Mike

Thanks for the link and reminder re the right tools. Yes I’ll be making a hub puller as per Buckland/ Robinshaw and others. ( knock on)
I’ve decided to use Susan M for the bearings this time.
Iain