Thread: Double Cardan Gone again!

Originally Posted by wardy1

About March last year my double cardan shattered whilst driving through Parramatta on my way back to Melbourne. Well I almost got caught again

Luckily this time I did get some warning that it was on its way out. Got some vibration and accelerating caused a bang on auto shifts. Got underneath and the whole thing looked like it was about 10 degrees out of square.
Getting a greasable job put in, cant stand having that worry hanging over a trip anymore.

Can anyone explain what the perceived 'advantage' was in this design, or is it just anothe LR **** up?

its to do with the achiveable "flex" available to the shaft

from memory it was either Toymotor or Nissan who did it first in automotive 4x4s.

Double cardan joints are used where the angles of the driveshaft to the diff are not equal and opposite, so that the speed differential of each joint do not cancel each other out.
The Universal joint has a quirk in that unless straight, the output vs the input slows and speeds up 4 times each revolution. ie the diff flange would change speed relative to the driveshaft.
In a double joint, the pulses are greatly reduced,virtually cancelling each other out.
So the Disco 2 probably has the axle flange pointing straight at the transfer, and the major angle out of the transfer case, where the double joint is.
Without it you will get more vibration, unless you changed the diff flange angle, so that the angle at the axle end is "equal but opposite" as possible to the angle at the transfer end.
Regards Philip A

From what other have reported with Disco II's, condensate from the air conditioning drains onto the double cardan joint.

If this happens with yours, you might divert it to one side.

Thanks guys. I will have a look at the aircon outlet once I get it back.

My freelander has a CV on the propshaft to deal with this sort of issue - wouldn't it have been easier to do the same on the D2.

Originally Posted by garrycol

My freelander has a CV on the propshaft to deal with this sort of issue - wouldn't it have been easier to do the same on the D2.

The double cardan joint is far stronger than the Rzeppa joint (both are so called CV joints) used in the Freelander, and is inherently more durable, everything else being equal (which it isn't - the angle in the Freelander drive train is far less). Although it seems that there is a detail design problem (that drain).

Toyota and Nissan copied the use of them long after Rover started using them in the Range Rover, where some form of CV became necessary when the nose of the diff was tilted up to point at the transfer case to allow a straight track rod to be placed behind the axle where it was protected better (earlier four wheel drive designs that had the trackrod behind the axle used a bent tie rod so the diff could remain parallel to the transfer case output shaft).

It is another example of the compromises needed in any car design.

In the 90/110/Defender, the use of a double Cardan joint is avoided by mis-phasing the U-joints on the shaft, on the basis that in a utility vehicle more vibration is acceptable than in a luxury vehicle. The problem with double cardan joints is that they are expensive, and the aligning mechanism, if worn, is not repairable.

John

Just out of interest, I recently fitted a D1 front shaft and output flange to a D2 to eliminate the front shaft while looking for a shudder.(Turned out to be the auto trans converter lock up clutch)
Anyway, It had NO more or less vibration, and drove very well.


JC

Originally Posted by Blknight.aus

its to do with the achiveable "flex" available to the shaft

from memory it was either Toymotor or Nissan who did it first in automotive 4x4s.

Ford "F" series 4WD's have had cardon joints since Jesus played fullback for Jerusalam, Bronco's as well, Regards Frank.