Thread: Disco 1 Driveline Vibration

Originally Posted by muddy69

LR gurus,

Will a castor correction/wedge kit fix the vibration in the driveline? Does caster correction have any effect on the front diff/driveshaft?

Any help would be appreciated!

In a few words NO castor does not cause vibration! Nor does camber. Castor effects the weight of the steering wheel and or steering effort. Camber if leaning the right way will make for better cornering and some tyre wear. The vibration may be the angle of the diff to drive shaft? Also check all of the bolts on your tail shafts front and rear I could do all of mine up another 3/4 of a turn and has stopped some of my vibrations.

Does this mean I need an aftermarket front/rear driveshaft or some sort of adapter to compensate for out of phase driveshaft/

I have read about other LR owners having to modify driveshafts when the suspension is lifted beyond 2".

Wedges are used for leaf springs, and your bumps stops are still fine, when the axle moves up, it'll move in an arc which will then align it again with the bump stop.

The fix for front shaft vibrations seems to be to fit a Disco2 front shaft which has a double cardin at the transfer case end. They are another story in themselves though. To do this you'll need a DC flange to fit onto the transfer case also.

Slunnie,

Excuse my ignorance, but what is the DC flange. Would you recommend that I could do this job myself (with help of friend) or should I let a driveshaft shop do it?

Thanks for your advice.

Muddy

Now that I look closer at your post, I assume it's a double cardan flange?

Can you recommend where I might get a decent Disco2 front propshaft and DC flange from? (In Melbourne)

Should I have the shafts checked by professional shaft shop to check them properly before changing out.

I have heard from discoweb to take the front one out, lock the cdl and take it for a short drive. This will enable me to work out which shaft is causing vibration. Is it common after 3" lift that both shafts can cause vibration?

Sorry to bombard you.

swapping to the DC flange (Double cardan flange) is a DIY if you know how to twist a spanner and have the appropriate sockets to fit the nut that holds it in.


A double cardan joint is essentially a do hickey that is made of 2 UJs assembled into about an 8 inch space think ultra short prop shaft and your on the right track.

installation is as easy as drop the propshaft, undo the big nut in the middle of the drive flange, pull out the flange, insert DC drive flange and replace the bits you pulled off.

be aware that if you install caster off set bushs the vibration will get worse. the diff pinon will become lower than where it is now. 2 degree is acceptable depending on how the vehicle drives.

glen

Originally Posted by muddy69

...Is it common after 3" lift that both shafts can cause vibration?...

With coil sprung Rovers, the engine and transmission is inclined down at the rear.

For correct alignment of the U-joints of the rear tailshaft, the rear diff pin is angled up at the front - so that it is parallel with the engine and transmission. These angles will remain reasonably parallel when the vehicle is lifted 3" and will not cause vibration in the rear tailshaft.

It was not practical to angle the front diff pinion down at the rear to make it parallel with the engine and transmission.

So the front diff pinion is angled up at the rear, which makes the u-joints out of phase. This would normally cause the front tailshaft to vibrate, but Rover rotated (at the slip joint) the front u-joint yoke out of phase with the rear u-joint yoke, so that the out of phase due to the angle of the diff pinion is cancelled out by the out of phase due to rotation of yokes.

When you lift the vehicle, the angle of the front tailshaft to the engine and transmission increases.

The radius arms angle the diff pinion up more. This is also why the castor angle reduces.

Because of the changes in the angles of the u-joints, the amount that they are out phase also changes. In some cases this is enough to cause a vibration. As Glen said, if you correct the castor angle using offset bushes, you will worsen the tailshaft vibration.

The best solution to front tailshaft vibration (due to suspension lift) is to use a double cardin joint at the t/case end of the front tailshaft.

As others have said, to use a Disco II front tailshaft, you need to also fit the Disco II drive flange to the t/case output shaft. It is wise to replace the oil seal while the drive flange id off.

There have been many posts about a problem with Disco II tailshafts, because they are not re-greasable and fail earlier than u-joints that are greased regularly. The u-joints should be replaced at the 1st sign of a problem - if not they can fail completely and cause a lot of expen$$ive damage (such as smashed gearbox case).