Thread: Defender swivel preload value?

The preload is not particularly critical. It needs to be enough to ensure there is no free movement and a bit of damping, but it takes quite a bit more to be enough to cause a problem - which would show up as poor self centring. So if it steers OK I would say it is OK. (I don't have any books with me) Note that the preload figure quoted is without seals, so you have to add a bit if the seals are in place.

Some fears have been expressed about shortening bearing life if too tight - but the preload is very small compared to the vehicle weight or shock loads on bumps, so I discount this.

From memory, late Defenders have a roller bearing top and bottom, and this will affect the specified figure.

John

Thanks for the response I think you have nearly responded to all questions re wobbles.

My defender is a 98 and has the dual tapered bearings just as you thought. Does this centre the swivel ball better than old designs?

Originally Posted by MinniTheMoocha

Thanks for the response I think you have nearly responded to all questions re wobbles.

My defender is a 98 and has the dual tapered bearings just as you thought. Does this centre the swivel ball better than old designs?

I don't have enough experience of the double roller bearings to answer that question. I suspect the change was to allow the fitting of ABS units to the swivel rather than to make any improvement to the steering.. It will also mean that there is relatively little damping compared to those with the top bush, making these vehicles more susceptible to wobble.

John

Originally Posted by MinniTheMoocha

My Defender suffered from slight wobbles especially when hitting bumps in the road particularly on the right hand side.

Previously I suspected wheel alignment but had that done about three times and the guys were sick of seeing me.

Checked front bearings and tightened them up a smidge which improved the situation. Installed a new steering damper, radius arm bushes, steering arms, panhard rod and each of them seemed to improve the situation. (These were all done progressively for other reasons not just to improve the wobble! eg. bent steering rod, bushes perished etc)

Well the other week I had to get one wheel swapped over as I had a dent in the rim and would rather the dented one as my spare.

The tyre guys swapped over the tyre to my good rim and away I go. Between 0 - 90km/h no problems so I don't detect it for a few days until I hit the freeway. As I go from 95-100km/h I get the nasty wobbles happening and back it off. I was thinking it was wheel balance had the wheel checked and it was fine so the problem persisted.

Using the search tool on Aulro I located a heap of discussions about this type of problem to check the swivel preload as well as panhard rod bushes, radius arm bushes, steering damper, tie rod ends etc. Now I had done nearly all except the preload.

I read up on Rave and it says the preload should be between 1.5kg and 2.5kg which is what the swivel appeared to have using the spring scales. In the hand however it felt a little loose to me with no real drag/resistance, you could flick it and it would just flop over.

I decided to remove one of the thinnest shims (I had four fitted) and it now has 3.5kg - 4kg preload using the spring scales. In the hand it felt smooth, no notchiness and not overly tight.

Went for a blast down the freeway and no wobbles at all, especially when hitting the sweet spot of 95-100km.

Tomorrow I should be able to give it a good run and hit a couple of bumps that I know upset the front end and report back.

So my questions are is this too much preload? And should the other side be matched with approximately the same preload? Note swivel seals were still in place when tested.

Thanks

I have the same problem, see my post Death Wobble visits me. Will be checking the swivel preload and take it further.

Hi MtM,

You may have already resolved this but for what it's worth....

My 08 Defender also developed identical 'wheel shimmy' problems at 95 - 100kmh on the freeway when down in Perth after 12 mths with no problems in the sunny Pilbara.

Had front wheel balance done (they said it was out) and as with you still had the shimmy at precisely 95kmh. Took it to 'specialists' (they said first mob hadn't done it right) and had balanced again - still shimmy. Took it to dealer, they re-balanced in own premises (said previous mob hadn't done it right) and still shimmy. They said probably lop-sided tyre.

Swapped front wheels to back, rear to front and still shimmy at 95kmh.

All other steering gear OK, vehicle steady on road, no wandering.

A friend suggested I ask to have swivel pre-load checked (never heard of it before although 5th Defender!) Pre-load was out and had to be shimmed & problem vanished.

If you have a look at a thread on 25/10/10 "Front diff/hub oil capacity" post #2 by Jock the Rock shows a page from a Defender TD5 on-line workshop manual. Point 47 reads "Check & Adjust Pre-load on Bearings. Resistance after initial inertia is overcome should be 1.16 - 1.46kg. Adjust by removing or adding shims to top swivel pin".

Hope this helps. Good luck!
Keith H.
Karratha
landroverwa

Interesting thread!
I may have the same problem. Could someone please tell me how much dismantling has to be done in order to check this? I looked in the Haynes but it shows the procedure as part of a complete strip down...

Ta!

Originally Posted by markyc

Interesting thread!
I may have the same problem. Could someone please tell me how much dismantling has to be done in order to check this? I looked in the Haynes but it shows the procedure as part of a complete strip down...

Ta!

Checking whether it is a problem is quite simple - jack up the front axle (on stands) and remove wheels (can be done one side at a time, but easier to do both at the same time); disconnect the tie rod (and the draglink on the left side) - this will require a suitable puller or usually judicious use of a hammer on the side of the eye will work; then use a spring balance to measure the force needed to turn the swivel after getting it moving. Since it has the seal in place, add 1-2kg to the book figure, although usually there will be no doubt if it is too loose - it will just flop from side to side with no effort at all.

To adjust the preload is a little more complex. Remove the nuts holding the top swivel pin; remove the bracket holding the brake pipe - to avoid having to disconnect the brake hose, it helps to convert the hole to a slot. Place a jack under the bottom of the swivel housing and then pry up the top swivel pin. Remove shims, retighten, check preload, repeat until you get the right figure. Ideally you need to unbolt the seal, but this will get oil or one-shot everywhere. A shortcut is to remove the entire stack of shims, tighten to the desired load, use feeler gauges to measure the gap, and then a micrometer nor vernier caliper to make up a stack of shims this thickness.

If you find that the preload is significantly less in the straight ahead position, or is not smooth through the full range of movement, then the full strip and replacement of at least some parts is indicated.

John.

Originally Posted by landroverwa

Hi MtM,

If you have a look at a thread on 25/10/10 "Front diff/hub oil capacity" post #2 by Jock the Rock shows a page from a Defender TD5 on-line workshop manual. Point 47 reads "Check & Adjust Pre-load on Bearings. Resistance after initial inertia is overcome should be 1.16 - 1.46kg. Adjust by removing or adding shims to top swivel pin".

Hope this helps. Good luck!
Keith H.
Karratha
landroverwa

Hi Keith,

Thanks for your comments, you may have missed in my notes that I did find what the official figure should be but my scales were showing that mine were within the 1.5kg - 2.5kg range. Although I had the swivel seals
in place and as John (JDNSW) says it can add 1-2kg to the reading. To add to the reading I had also left the brake calliper and brake line attached which I am sure affects the force required to move it.

I was worried it might be a little too much preload which is why I posted the question but having read the latest post from John (JDNSW) I am pretty comfortable that it is not excessive.