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Steering wobbles


disco_al

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Are we sitting comfortably, good then i shall begin.....

It started last weekend after changing the steering damper on my disco for a nice shiny new one :). After changing it i noticed that whenever i hit a bump in the road at anything over about 40mph, the steering would develop a severe "shimmy", similar to the effect you get when the wheels are out of balance. I knew that the n/s shock was a bit suspect, as it had always felt that the wheel was double bouncing over potholes, and that the wheels were not out of balance as they were fine before changing the damper, and i checked the suspension bushes last week, and all appeared fine there too.

No problem thinks I, pair of new HD gas shockers required :) so i got some in and fitted them last night, quick road test later and it was still shaking after hitting a bump. I jacked the NS front up (it's that side that seems worse) and gave the wheel a wobble, nothing at 12/6 o'clock, but a bit of play side to side, so after checking the steering joints i found that the drop arm ball joint had some play in it, and after checking Rave, found that the drop arm joint can cause steering "shimmy" .

Tonight i have changed the offending item, and the wobble is much less pronounced, but it is still there :angry:, the rest of the steering joints appear fine, no up and down movement to be found, although you can twist the track rods/drag link around their axis. The swivels are fine, as are the top and bottom swivel bearings, wheel bearings are fine as well, no play there.

So, does anyone have any ideas as to where i should check next? would a new damper highlight the play axial twist in the other steering joints?

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preloads were fine when i replaced the top and bottom bearings (and o/s cv joint) earlier this year, it just seems strange that it started after changing the damper. i will have to check the damper mounts and change the TRE's tomorrow (if it stops raining long enough)

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preloads were fine when i replaced the top and bottom bearings (and o/s cv joint) earlier this year, it just seems strange that it started after changing the damper. i will have to check the damper mounts and change the TRE's tomorrow (if it stops raining long enough)

Hi my guess would be your preload's or poss a mix of preload's and loose or worn wheel bearings.

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right - update time. changed both the n/s track rod end and the drag link end, re checked the pre loads and made a slight adjustment to both sides, which appears to have made a slight improvement.

but, it still has a shake when i hit a bump. could it be the hockey stick bushes and the panhard bushes causing a problem? there is some side to side play, but no more than you would expect from a rubber bush

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Hi my guess would be your preload's or poss a mix of preload's and loose or worn wheel bearings.

Good morning Disco-Al,

I went through the same pains, and eventually found the source to be the "dead-ahead" free play on the steering box. My Disco I 300 Tdi's steering box has an adjustment bolt on top of the steering box. This adjuster is locked with a nut. The top of the adjuster takes an Allen key. The Haynes and land Rover Manuals describes the "hand-on" method to do the check and adjustment.

I followed the instructions, and no more shimmy. :rolleyes:

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I went through the same pains, and eventually found the source to be the "dead-ahead" free play on the steering box. My Disco I 300 Tdi's steering box has an adjustment bolt on top of the steering box. This adjuster is locked with a nut. The top of the adjuster takes an Allen key. The Haynes and land Rover Manuals describes the "hand-on" method to do the check and adjustment

Did that last night - and it still shakes when you hit a bump in the road (and if anyone knows Herefordshire roads they are all bumpy)

Any more ideas guys? it's getting annoying now :(

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the damper i fitted was a brand new monroe unit, that i was given by a friend who fitted it on his RRC, which never actually saw the road. i still have the old one, so will refit that one and see what happens, as it was only since changing it that the wobbles started.

keep us updated as mine has the same tendencies.

i will keep things updated as i go along, i will solve this one - somehow.......

i think you are only about 20 mins away from me.....

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I have had the same issues recently. I've added a second, relocated steering damper, the original is still on but is completely useless. I've had a big improvement by polybushing the radius arms - it's still there at speed but different in character. Less a shimmy and more a shake - it now feels lots less scary and out of control when it starts but I'd like to eliminate it completely.

I'll have to work down the list as you have I think.

Good luck and let us know how you get on, Stu.

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I take my previous comment back, polybushing the radius arms has had no positive effect on my steering issue at all!

I had a major moment on the M6 this morning, a series of bumps in the middle lane at 70mph set me shaking all over the place - the worst one yet. It seemed like about 10 seconds of really bad shaking and bouncing, I had to slow down to 40mph to get it under control.... too scary.

The poly bushes have improved general road manners but tightening up the axle to arms must have made the component(s) that is really at fault more stressed/isolated when the shaking starts.

I'm going to go have a good wrench on all my bushes and joints etc to see if I can find any play - this has got to be sorted, I use the truck every day to get to work!

Stu.

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It seemed like about 10 seconds of really bad shaking and bouncing, I had to slow down to 40mph to get it under control

that is exactly what mine does. everything is fine below 45-50mph, but hit a bump at anything over that and it shakes better than shakin' stevens ever did

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Hmmm. Nothing obvious mores the pity. Looks like I'll have to do the swivels.

I'll replace the panhard rod bushes while im at it, that should narrow down the possibilities if it doesn't solve the problem.

Can anyone reccomend a quality make/supplier of swivel service kits?

Stu.

EDIT: Reading through the tech archive article on replacing the swivel I've noticed that there is no description of how to set the pre-load. Can anyone point me in the direction of a how to? If I can just reset them rather than replace for the time being that would be ok. Cheers.

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Get yourself a spring balance

Spring_Balance.jpg

Disconnect the TRE and use the hook in the hole in the arm on the swivel. Pull on the balance in line with where the steering arm was so as to move the swivel. Just before the swivel moves (or after initial resistance is over come) the balance should read 4lbs without the swivel oil seal fitted, or in your case 12lbs with the oil seal fitted.

I would start by removing the thinnest shim first. Also support the hub with a jack so that the weight of the hub doesn't cause the seal around the swivel to open up and let the oil out................but then if you are using one-shot grease.......

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Get yourself a spring balance

Disconnect the TRE and use the hook in the hole in the arm on the swivel. Pull on the balance in line with where the steering arm was so as to move the swivel. Just before the swivel moves (or after initial resistance is over come) the balance should read 4lbs without the swivel oil seal fitted, or in your case 12lbs with the oil seal fitted.

I would start by removing the thinnest shim first. Also support the hub with a jack so that the weight of the hub doesn't cause the seal around the swivel to open up and let the oil out................but then if you are using one-shot grease..

been there done that - along with drop arm joint, track rod ends and drag link ends, steering box free play adjusted and steering damper replaced (going to put the old one back on to eliminate that as being faulty) as well as two new front shocks (HD gas ones)

just soime superpro bushes to fit now and then hopefully problem solved

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I would start by removing the thinnest shim first. Also support the hub with a jack so that the weight of the hub doesn't cause the seal around the swivel to open up and let the oil out................but then if you are using one-shot grease.......

Thanks Andy, good advice there. If I could just get you to clarify though, where are these bloody shims??

Thats the only bit I'm not sure about, I've stripped both fronts down including removing the stub axles in the past to change bearings/remove welded on remains etc and filled both with one shot grease after spilling EP90 all over the drive but cant recall ever seeing anything "Shimmy" (No pun intended :rolleyes: )

Stu.

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Get yourself a spring balance

Spring_Balance.jpg

Disconnect the TRE and use the hook in the hole in the arm on the swivel. Pull on the balance in line with where the steering arm was so as to move the swivel. Just before the swivel moves (or after initial resistance is over come) the balance should read 4lbs without the swivel oil seal fitted, or in your case 12lbs with the oil seal fitted.

I would start by removing the thinnest shim first. Also support the hub with a jack so that the weight of the hub doesn't cause the seal around the swivel to open up and let the oil out................but then if you are using one-shot grease.......

Must one remove the calliper, as the flexable brake fluid hose must shurly have an effect on the force required to move the swivel?

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Thats the only bit I'm not sure about, I've stripped both fronts down including removing the stub axles in the past to change bearings/remove welded on remains etc and filled both with one shot grease after spilling EP90 all over the drive but cant recall ever seeing anything "Shimmy" (No pun intended )

the shims are under the top swivel pin - remove the two bolts that hold the top pin in place (and the brake pipe bracket) and they should be under there.

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Guest DiscoTD4

Are you sure you have fitted the steering damper correctly as it does seem the cause and affect are directly related to the changing of the steering damper, so I think you need to concentrate your efforts there ?

As you know there are two bushes/washers at each end of the damper suds, I think the washers need to be fitted the correct way round as from memory one of them has a top hat to fit inside the mounting bracket on the trackrod / anti-roll bar. If they are not fitted correctly or too loose then there may be play in the system.

In which case the damper will be rendered useless, as it's main function is to arrest small resonant movements in the steering. It's desinged to elimninate the symptons your experiencing.

I'd go back and take a good look at how the damper is fitted, checking for free play with levers etc. It needs to be really snug.

Good luck and keep us posted

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Refitted the damper as per the instructions in the RAVE manual, so should be ok. Will have to double check it again to be sure though (the old measure twice - cut once comes in here, although no cutting involved - yet)

Definately no free play in it either - done up nice and tight, checked the mountings too and they are tight as well.

I will substitute the old damper when i get five mins, just to make sure it's not a faulty replacement, which would be unusual for a monroe item.

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Well, I managed to set the pre-load on one of the swivels and it was way out to start with. Unfortunately, due to a spinning, knackered track rod end I couldn't do the other. It was too late in the day to get a new TRE so cutting it off wasn't an option. I think there has been an improvement but I'll need to get some new TRE's (All goosed) and do the other swivel to eliminate them from the equation.

Glad I did the job though, I discovered my O/S wheel bearing was using orange grinding paste for lubricant so got that cleaned up and re-greased. I've found a nick in the mating face of the stub axle so I think theres alsorts of mud and water getting past the seal into the bearings. Looks like a new set of bearings and a new stub axle will be required.

Seems like every job spawns another two!

Stu.

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Guest DiscoTD4
Refitted the damper as per the instructions in the RAVE manual, so should be ok. Will have to double check it again to be sure though (the old measure twice - cut once comes in here, although no cutting involved - yet)

Definately no free play in it either - done up nice and tight, checked the mountings too and they are tight as well.

I will substitute the old damper when i get five mins, just to make sure it's not a faulty replacement, which would be unusual for a monroe item.

How did you get on - any different ?

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