Need some input from the collective wisdom…. I just purchased a CV axle setup for my ‘67 DHC 45/7190 restoration from Ray at RD Enterprises. Issue 16 housings, if that matters. Beautiful piece of kit. But I find that the hole pattern on my stub axles (both sides) doesn’t quite fit the outboard end of the CV axle. Ray hasn’t run into this before - has anyone else? I could enlarge the holes slightly and make it fit; would that be acceptable?
Joel
Not sure by how much the hole size differs but when I fitted mine I used a drill of exactly the same size as the bolt (7/16 from memory ! ) just to clean out the holes in the stub axles and diff output shafts. This just removed any corrosion / dirt that had accumulated over the years without changing the original size of the hole.
Hi Joel,
I bought mine from Kelvedon Lotus and had the same snag. The screws in the CV joint did not quite line up with the holes in the shafts. But it was only a little misalignment and was soon corrected with a file. I have heard of this before. I think the accuracy did not matter as much when bolting to a rubber component. I think it will be fine.
Cheers
Eric in Burnley
`1967 S3SE DHC
It’s possible someone had replaced the outer axle with an early type, which has a slightly different
PCD.
I struggled to get CV studs into my half shaft holes at hub and diff ends..Looks so straightforward when Ed China taps 'em in on the Wheeler Dealers Elan episode ! Noone tells you the manufacturing tolerances are variable and I was nervous to open the holes, but the tolerances are variable and some fettling is often necessary, beyond just cleaning and derusting the holes..
I drilled out the holes with a 11.2mm bit, a dremel and to finish, a 29/64 hand reamer (I was amazed this stuff even existed !); this was enough to get a snug sliding fit..The nominal size of the 7/16 bolt is of course 28/64 and I read a post on our forum of someone using an 11.4 mm drill bit..so it’s all in that ballpark..Tony
Fitted mine last year. No issues. Wonder if the issues lie in the lotus parts as there was perhaps more tolerance afforded by the rotoflexes than the CVs?
Tim
I think Eric Bushby is correct and that the error is with the original Lotus components not needing to be precise as they bolting to a rubber coupling. Being a fussy old bugger I measured the error and found that the worst of the four was out by 0.025”. Whether this matters I do t know, perhaps someone has knowledge of acceptable levels of eccentricity for drive shafts.
Richard Hawkins
Interesting that my enlargement of the nominal 7/16 holes to 29/64 ie. 1/64 is 0.017" ,in the same ball park as Richard’s 0.025" measured tolerance variation…Tony
Thanks everyone for your responses. Very reassuring.
Joel
Hi,
I had this problem as well with the kit from Kelvedon, they claimed they had never had it before! It was out by miles.
But they sent me a new set of the bell ends with the studs so I had to disassemble my brand new (‘and not cheap) shafts and refit the substitute new ends. It worked but then the shank of the stud would not pass through my equally new diff and hub shafts without emery clothing down to fit. A job I had thought would take me half a day ended up as 8 days.
It is a very common problem as the PCD tolerancing on the Lotus components was very loose as the rubber donuts could accommodate the variation. You need to ream out the holes a little until the bolts fit. Bending of the arms over the years does not help either
The Elantrikbits design allows for this issue with a small degree of movement in the captive bolts rather than using rigid studs
Any supplier who says they have never seen this before is talking BS
cheers
Rohan
The “loose tolerance” idea makes some sense, but I have checked the spacing on all the hub shafts and axle shafts I have and they’re all exactly the same.
Out of curiosity, I had checked the fit of my to-be-discarded halfshafts with the CV joint stud plates and they fitted well..this implies likely they were both properly centralised, so the problem was the holes in the brake disc/hub and the diff output shafts..As I said earlier, reaming the holes, and not being squeemish to do so, was the answer..Tony
And ream I did…. now just under 29/64ths and there’s still a long way to go. My guess is they’d have to be 15/32nds at least; I’m not comfortable going that far. I checked the stub axle fit to the new brake discs and they’re perfect. I’m convinced the outer end of these CV axles just aren’t right.
I agree. Are the struts issue 16 or issue 18? Early car with issue 16 struts used a slightly larger pcd for the ‘tripods’ (diff output, half shaft and hub shaft), and if you have early shafts I’d definitely replace with modern billet items.
Issue 16, but not early
Hi
Issue 16 were l used on early cars up to S3, but the large pcd shafts were phased out early in S2 production, but are a direct fit in issue 16 struts, and have 2 identical bearings per hub unlike the issue 18 struts which use a wider inner hub bearing. You may well have some v early shifts. I certainly did on my S1 and had the same issue when fitting CVs.
I don’t think so. From what I can glean about the PCD, these are the later ones.
Thet should fit then..
Measure up precisely the PCD on the CV bolts , the brake disk and the hub shaft and report the measurements. That will tell you where the problem lies.
regards
Rohan