Lotus Elan

cv replacement

PostPost by: collins_dan » Fri Dec 05, 2008 8:20 pm

I'm about ready to reassemble and reinstall my cv jointed driveshaft. Everything on it was loctited together, which has made it a real pain to take apart to replace a simple torn boot. I'm wondering if I really need to loctite the inner joint to the drive shaft, it has a circlip to keep it from coming off? Should I loctite all 12 bolts, inner and outer? I was thinking of bolting everything back on, then taking it for a drive to make sure everything worked OK, then maybe just loctiting every other bolt? Finally, what torque setting should I use on the bolts? Thanks for the advice. Dan
User avatar
collins_dan
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1153
Joined: 09 Jan 2006
Location: Baltimore, MD

PostPost by: RotoFlexible » Fri Dec 05, 2008 8:51 pm

FWIW - when I installed the kit last spring, I didn't use Loctite anywhere. Lacking a torque figure, I tightened the black socket-head bolts "pretty tight" but not "really tight." After driving the car a short distance, I snugged them up (didn't take much). On subsequent checks, they have shown no signs of loosening. I will check them again while the car is up in the air this winter.

The bolts furnished with my kit have radial serrations under the bolt head that act as integral lockwashers. This may be sufficient to hold everything together.
Andrew Bodge
'66 Elan S2 26/4869
I love the sound of a torque wrench in the morning. Sounds like... progress.
User avatar
RotoFlexible
Fourth Gear
Fourth Gear
 
Posts: 681
Joined: 01 Sep 2005
Location: Eastern Massachusetts

PostPost by: rgh0 » Fri Dec 05, 2008 11:22 pm

A small amount of loctite medium strenght thread locker on a couple of threads of each bolt will help ensure the bolts stay tight and will not effect these ease of removal. You do not need it anywhere else. The inner cv to shaft spline joint should be a light push fit and does not need loctite and is retained by the circlip as you observed.

cheers
Rohan
User avatar
rgh0
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 7491
Joined: 22 Sep 2003
Location: Melbourne, Australia

PostPost by: memini55 » Sat Dec 06, 2008 12:26 am

Dan the three sets we are using all do not have loctite but do have the type of bolt Andrew discribed. They are all torks head and are tensioned to 15 ft lbs. We check them from time to time and have never found any bolts loose.

Mark
User avatar
memini55
Third Gear
Third Gear
 
Posts: 474
Joined: 09 Jan 2004
Location: Mount Vernon, Iowa

PostPost by: 66S2 » Sat Dec 06, 2008 5:34 pm

Circlips = Yes.
Loctite = No.
Problems = Zero after 20 years.
66S2
First Gear
First Gear
 
Posts: 25
Joined: 10 Oct 2003

PostPost by: ecamiel » Sat Dec 06, 2008 11:48 pm

Every nut or bolt on all my projects has either anti seize or some grade of thread sealer or locker. It just makes life so much easier later on.
Blue locktite is great stuff for sealing threads so they don't rust together but leaves them easy to take apart.

It is particularly important when using dissimilar metals such as plated bolts, stainless into aluminum, anything into magnesium etc.
User avatar
ecamiel
Second Gear
Second Gear
 
Posts: 218
Joined: 02 Oct 2003
Location: Ct. USA

PostPost by: collins_dan » Mon Dec 08, 2008 10:37 pm

Alright, everything is back on the car and when the temp gets above freezing, I will take the car for a ride. How will I know if everything is working properly? Any odd noises or feelings I should be sensitive to? Any disaster checks, like going over a speed bump on an angle that will truly test the system at a safe speed.

My concerns comes from the fact that while all parts seemed in good order, I repacked both joints dry and they moved very freely, occasionally hanging up, but I wrote it off as me over-rotating and the joints being dry. Once packed with grease, they seemed better, but would still get stuck when rotated certain ways, likely far more than they would in real use.

So now I've got myself overthinking everything. Wondering is the ball bearings should have been centered in the ovals... no one ever mentioned it, but one more thing to worry about if you're overthinking.

Any thoughts or reassurances appreciated. Dan
User avatar
collins_dan
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1153
Joined: 09 Jan 2006
Location: Baltimore, MD

PostPost by: rgh0 » Tue Dec 09, 2008 1:43 am

The balls and cages naturally self centre so you dont need to worry about that.

3 things to check on assembly

1. No significant backlash in the joints i.e the only backlash you should be able to see or feel should be in the diff itself
2. The drive shafts should be able to freely end float in the cv's and the bellows clamped on the shafts so that the shafts end float is approximately centred by the springyness of the rubber bellows at normal ride height.
3. At full droop the shafts can turn without any binding in the cv joints and there is still a little end float left in the shaft. Any binding can be felt as a small resistance as you turn the wheel when a ball in the cv joint gets to the end of its travel in its groove

If all the above Ok then you should have no problems in use

cheers
Rohan
User avatar
rgh0
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 7491
Joined: 22 Sep 2003
Location: Melbourne, Australia

PostPost by: collins_dan » Tue Dec 09, 2008 2:07 am

1 & 2 seem OK, but on 3, there is a slight resistance at a couple of points of rotation, but its not much. Could it just be air in the system? I reassembled dry and then packed from the outside, a little grease came through, so I packed the inside. What do you think? Thanks. Dan
User avatar
collins_dan
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1153
Joined: 09 Jan 2006
Location: Baltimore, MD

PostPost by: rgh0 » Tue Dec 09, 2008 2:47 am

The slight resistance at a couple of points of rotation at full droop is probably the cv's binding due to much deflection. Try jacking up the wheel a little to reduce the droop to see if the binding goes away. If it does you need to reduce the droop with a limiting cable.

regards
Rohan
User avatar
rgh0
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 7491
Joined: 22 Sep 2003
Location: Melbourne, Australia

PostPost by: collins_dan » Tue Dec 09, 2008 3:19 am

Thanks. When I installed them, I jacked the wishbone up, so that it would be easier to install the driveshaft and didn't notice any resistance in that position. Why do you think I am having resistance at the end of the groove with at least one of the ball bearings? Appreciate your help. Dan
User avatar
collins_dan
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1153
Joined: 09 Jan 2006
Location: Baltimore, MD

PostPost by: rgh0 » Tue Dec 09, 2008 6:45 am

At maximum deflection the angles adopted by the tracks the balls run in leads to the balls binding under torque load. This is what sets the maximum limits a cv joint can deflect to. Generally the design of the cover that bolts onto the cv joint that the shaft comes out of also matches that maximum angle so the shaft starts to bind on the cover at the same point.

No fix for it just limit the angular deflection as needed for the cv's you have. Only typically a problem in droop as bump angular defelction substantially less.

Some CV joints will accept more angular deflection than others due to their detail design . The genuine Lobro CV joints for the VW combi were the best in this regard I believe.

regards
Rohan
User avatar
rgh0
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 7491
Joined: 22 Sep 2003
Location: Melbourne, Australia

PostPost by: paddy » Tue Dec 09, 2008 8:51 am

I fitted Col Croucher's CV driveshafts (with lobro joints) and on one side got a very slight binding on full droop, but the wheel could still easily be turned by hand. However, after a few miles driving the joint had loosened sufficiently and there was no perceptible binding at all.

If the resistance you're feeling is very slight, I'd be inclined to see what happens after things have bedded in.

Paddy
1963 Elan S1
User avatar
paddy
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1190
Joined: 27 Oct 2008
Location: Woking, Surrey

PostPost by: collins_dan » Tue Dec 16, 2008 7:31 pm

1st drive was uneventful. I'll check everything over again before my time out. Now, its on to engine, gearbox and differential mounts. Dan
User avatar
collins_dan
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1153
Joined: 09 Jan 2006
Location: Baltimore, MD

PostPost by: cocky » Wed Dec 17, 2008 8:25 am

I recently fitted Kombi CVs and had no resistance on full droop. They are a little larger in diameter (approx 9mm) and seem to have greater angular deflection.
Cheers,
Chris
1964 S1 (Now sold)
cocky
New-tral
 
Posts: 14
Joined: 02 Jun 2008
Location: Melbourne

Total Online:

Users browsing this forum: No registered users and 7 guests