New vibes after 2¨ lift

[bill van snorkle]

I don't understand your logic on this at all.

Putting a lift in raises the nose of the diff.

If you look at the second picture, which was taken level with the door tops, the ruler indicates that the diff nose is too high.

By that logic, the nose needs to be lowered

You must bear in mind that the transfercase out put is not parrallell with the vertical door lines and it is more important that the universal joints are close to equal than being parrallel with any other part of the vehicle.

The different geometry between the trailing arms and the A frame is not perfect at maintaining equal universal joint angles throughout the suspensions range of vertical travel, and neither does it need to be because the angles are set at the design stage to suit a given height, and any alteration to that height require that the angles be reset.

I thought my suggestion to cure your problem was an ideal one to make to an Irishman as t wouldn't cost you any money to try , and as Pete has already mentioned it has been known to work. Automotive design doesn't always conform to standard engineering practice or logic. A good example of that is the front end in that the drive flanges at the diff and front output of the transfercase are not even close to parrallel, but at opposite angles. To be parrallel the diff pinion would be almost dragging on the floor and the universal joints would be operating at a very severe angle indeed. The solution LandRover chose was to tilt the diff higher so that the universal joint angles are still more or less equal, but opposite instead of parralell. This method together with changing the UJ phasing still works to cancel vibration and gives lower opreating angles to allow for a wider range of suspension travel.

Bill.

[Bush65]

Just to add to Bill's posts, by way of explanation as to why the rear suspension does not maintain parallel u-joints when the suspension is lifted.

If the upper and lower suspension links were equal length to maintain parallel u-joints, there would be an unwanted side affect from rising anti-squat. Too much anti-squat causes the rear suspension to hop while climbing a hill, and if the anti-squat rises as the axle droops, the rear suspension hop would be unstable.

As Bill said, it is not necessary for the u-joints to be parallel through the full suspension travel. Only at normal ride height.

Because the upper links are shorter than the lower links, the pinion is rotated down as the axle droops, or when the suspension height is raised. For this reason it is necessary to rotate the pinion up as advised, when the suspension is lifted.

As Bill said, you should compare the angle of the pinion flange, to the angle of the flange/brake drum at the t/case. Within 2 to 3 deg of each other is usually acceptable.

[Gromit]

All very interesting reading, I understood most of it .

So, I tried Bill's suggestion and moved the bushes on the chassis to the front side of the bracket. This lifted the flange of the diff by 15mm.

The vibrations are still there, but might be slightly improved.

Here's what it looks like now. Bear in mind that the camera angle skews it somewhat.

The angle at the diff is almost straight, while the t'box end has a fair angle on it.

So, given both theories so far, I'm at a loss as to what to do next.

Pull the diff up further so that it's straight, or lower it so that ends of the prop shaft are parallel.

As bill says, that's going to be pretty low.

[SteveG]

So, I tried Bill's suggestion and moved the bushes on the chassis to the front side of the bracket. This lifted the flange of the diff by 15mm.

The vibrations are still there, but might be slightly improved.

Excellent!! Bush, flange and vibrations - all used within two sentences

Steve

[western]

Excellent!! Bush, flange and vibrations - all used within two sentences

Steve

Hmmm, think we all know what you were thinking about

[western]

Gromit, Just taken these of my 110 on OME 754 rear springs, , thought these would help as a comparision.

1st the lower flare edge is 36inches above the ground & from centre of the hub cap to flare lower edge is 20.5 inches [with 400kgs of kit in the back, this is normal use conditions]

2nd rear diff/prop uj angle

3rd diff flange bottom from ground

4th transferbox uj angle

5th diff uj

6th rear axle taken from gearbox looking backwards

hope they help

[Guest diesel_jim]

You can buy a kit from LR for rovers (althoug i think it's for 90's) fitted with HD suspension.

it consists of some spacers that mount by the triangle chassis bush to space it out a bit.

part # IPV 000010

[western]

Spacer also listed in EPC but different part number [maybe earlier version] KVX000010

[Gromit]

Ralph,

Thanks a million - I really appreciate you going out and taking pictures

I´ll do a comparison in the morning and decide where to go from there.

[Gromit]

Just realised my sliding joint is at the other end

I thought the bolt pattern was different at each end.

[bill van snorkle]

Just realised my sliding joint is at the other end

I thought the bolt pattern was different at each end.

That could make a difference, particularly if the slip is loose and can wobble a little. Failing that you may have to get or make one of those A frame ball joint relocating brackets and arrange it to tilt the diff higher. I missed the fact that yours is a LWB. Moving the bush to the front of the bracket makes a more dramatic difference to uj angle changes.

Bill.

[western]

happy to help, can't have a 110 feeling ill,try the prop same way as mine before going any further, no vibrations at all on my 110.

[Gromit]

try the prop same way as mine before going any further, no vibrations at all on my 110.

Will do. After discovering this, am tempted to go out and do it now, in the dark. The neighbours might think I was a bit mad though

[bill van snorkle]

Why does the ''Edit'' function keep disappearing on this thread?

Bill.

[Bush65]

I notice in one of your pics that the boge leveler is still fitted. The leveler tries to retain a certain height, but you have lifted the suspension, which rather defeats what the leveler is trying to do.

But returning to u-joint angles. For the rear tail/drive/propeller shaft, the angles should be close to the same to avoid vibrations. It does look like the pinion is angled up too far.

Have you had a good look for any problems around the ball joint for the A-frame (upper links). There is the plate that bolts to the diff housing and the welds of the housing.

[dollythelw]

Im gonna go with the pinion too high camp - I can send you over my inclinometer and you can make the comparison between the transferbox flange angle and the diff nose angle, I'll get some spacers punched out as well

[Gromit]

Bush65, yes the self-leveler is still on, as I can't figure out how to get it off. Anyway, I don't think it makes much difference as it has become a dark green long-necked seabird, what's it called, oh yes, a shag.

Anyway, I've been faffing about with this all day. After a brief forray into landrover engineering I've returned to the conclusion that the diff nose needs to be lowered.

I put the prop on the right way round - no change.

Loaded my ton of blocks into the back - still noisy

Moved the chassis bush back to their correct position (still with the blocks in) - fixed.

So, as per Jez's suggestion, I thought I'd measure the t'box and diff angles and then remove the blocks and remeasure. Unfortunately my setup of a flat edge, spirit-level and set-square (and also a plumb line afterwards) was not accurate enough to record a change in either angle when the load was removed.

Loaded and unloaded showed an angle of about 4 degrees between the t'box and diff. I reckon that it is just on the tolerable limit when loaded, and goes over when unloaded.

So, I'm thinking I'll just shim it and see. I very roughly estimated that 2 degrees at the diff equals 6mm where the trailing arm bolts to the chassis.

Jez, if this makes sense to you, could you make me up some shims, about 6mm? I'll send you some beer tokens.

Lastly folks, don't waxoil your truck if you intend working on it at any point in the future. I'm off now to burn my cloths and tools.

[western]

you can remove the boge strut, needs a very slim open end spanner at the bottom or just cut off the joint complete with the cup from the rear axle mount [see my pics for the lower cup location] & unblot the top mounting from the chassis x-member 4 bolts [can't remember the hex size of the bolt head/nut]

[Gromit]

you can remove the boge strut, needs a very slim open end spanner at the bottom or just cut off the joint complete with the cup from the rear axle mount [see my pics for the lower cup location] & unblot the top mounting from the chassis x-member 4 bolts [can't remember the hex size of the bolt head/nut]

Cheers, yeah, that's what a reckoned, but I don't have a suitable spanner for the bottom at the moment, and the top nuts are a mass of rust and need to be cut off and I can't get the grinder in there. One job at a time! I'll get my bad vibes sorted and then think about the strut.

[western]

IIRC I used a hammer & chisel to get the slim nut moving.

[dollythelw]

Im on the case fella

[Gromit]

UPDATE:

So jez's disco biscuits arrived today.

It took a bit of chockage of the front wheels and reversing to get the rear axle to move back to get the shims in.

Aren't they lovely.

This moved the nose of the diff down by about 7mm.

Before:

After:

So I went for a test drive....

and the vibrations are....

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.....GONE

Thanks to everyone for their advice, and to Jez and Vinny for spinning the shims up on the lathe.

[dollythelw]

sweet

[western]

your back to a shake free drive then, well done for sorting it.

[Andicog]

I wish I'd found this thread a while back,  lifted my 110 using old man emu springs,  +40 mm lift,  had a really bad rattle on neutral throttle,  bought wide angle props,  smoother but still there,  bought kinked trailing arms,  no difference.    The only thing that got rid of the noise was putting a bit of weight on the back.  

Spoke to a few people who are supposedly in the know,  one said lift the diff nose up and the other,  who actually makes adjustable trailing arms said the diff nose angle does not change with suspension movement at all,  even though I asked about the arms being a different length to the A frame he insisted that the angle won't change. . . . 

Then I see this thread . . . Bloody spot on!  I managed to find a pair of genuine land rover chassis to bush spacers,  now all seems quiet and much smoother.  A 10mm spacer moved the nose down 12 mm ish and now the prop u/j angle   at both ends looks much better.  Thanks again guys. See photos.