A gentle steering wobble under braking

[chadr]

I've been following Ryan's thread on similar symptoms with his 80 and thought I would post this here, rather than hijack his thread;

I've been experiencing a gentle steering wobble under braking for a few hundred miles/weeks now - as I say it is relatively gentle, sometimes no more than a constant tremor - but certainly one that is noticeable. It's always under braking only and if anything, seems more pronounced under gentle braking rather than hard. The steering is otherwise spot-on.

So some background;
The tyres are all good with plenty of tread and even wear.
The tracking and alignment is spot on and was done only a few months ago (not aware of any bumps or "accidents" to have made it change).
The brake discs were changed all round to Mtec grooved and dimpled discs, along with OEM brake pads about 4k miles ago, when all 4 brake calipers were also refurbed. Braking was certainly improved and still work very well, apart from this steering wobble of course.

I might get the wheels swapped front to back, just in case one of them has gone out of balance. I also haven't had a chance to take a look at the pads but will check those too and see whether there are any obvious pointers.

Reading Ryan's thread, it seems that (worn) front bearings might also be part of the issue? My truck has done 172k miles and is 19 years old. Apart from the lower ball-joints, which were replaced last year, I'm pretty sure that none of the other front components have been replaced, so all OEM.

Thanks in advance.

 

[silvercruiser]

if you have been through all the other bits it could well be a wheel bearing. have you jacked it up and felt for any play?

 

[chadr]

No, not yet Joe.

However I seem to vaguely recall Trevor or Ed mentioning something about the bearings when I had my lower ball joints replaced. (Though it could well be my imagination! ).

Do you know what's involved in replacing them? Is is a big job?

And while I'm at it, is there any other preventative maintenance work that might be useful to get done at the same time?

 

[silvercruiser]

i will admit i have never done a wheel bearing on the landcruiser.

 

[BobMurphy]

i will admit i have never done a wheel bearing on the landcruiser.

Oh but I have . . .

They are monsters and I'd be surprised if they are worn (mine weren't, but I replaced them anyway).

You have to remove the steering knuckle (e.g. remove trackrod, ABS wiring, Brake hoses) separate hub from drive shaft (one nut), Undo top and bottom Balljoints, remove circlip and press the hub + bearings out of the knuckle.

The hub then has to be pressed out of the bearings.

Some have found the assembly to be very tight, requiring a 25 ton press. I have a 30-ton press but mine only needed around 10 to 12 tons to shift ( Only ).

I made up a very heavy-duty support for the knuckle while the hub was being pressed out.

Before suspecting the wheel bearings - check the track rods and steering links for play, particularly at the steering rack end.

Good luck .

Bob.

 

[chadr]

Thanks Bob.

The track rod ends and sterring rack bushes etc. were all replaced in 2012 @ 150k - so 4 years/23k miles ago, when the truck was failed on an insecure steering rack (online MoT History is great isn't it!!).

This weekend I'll start with the wheels, steering links etc. and a visual inspection of brakes and take it from there..........

 

[Beau]

What about inner tie rods? I need to replace mine as there's slight play which is causing a similar pull/wobble when braking hard. 190k miles so it's about time really...

 

[whitemr2gt]

I have the same symptoms on mine. I've recently been replacing a bunch of items, outer tie rods, lower ball joints, new rack bushes. I have a new pair of inner rack joints there to put on, but last I looked, i think the play I have (which isn't much, but subtle enough to notice) is in the steering rack shaft itself. With the front wheel (drivers) jacked up when I shimmy the wheel I can see a tiny bit of up/down movement on the shaft. My inner joints look OK. So I'm interested in whatever else you discover, otherwise the next thing I was going to look at was to replace the rack - which is otherwise fine, it has no leaks..

Sent from my Nexus 5 using Tapatalk

 

[whitemr2gt]

Have to slide you rack boot out of the way to check for play. So have a zip tie handy or a spare metal band to refasten it.

Sent from my Nexus 5 using Tapatalk

 

[Shayne]

It may be worth mentioning while your investigating that worn panhard rod and trailing arm bushes caused handling issues on my truck that i can't even begin to explain , i replaced them a long time ago so can't remember if braking was involved i just remember feeling the truck was somehow unbalanced

 

[Helijock]

I changed the front disks and the shimmy went.

 

[chadr]

That's what I'm afraid of - I hope they haven't warped or whatever as I only changed them last year/4-5k miles ago.

 

[Valli]

I recently started to notice this in my 95 series so I called a good friend how is a car mechanic and they do a lot of work on Prado's. He told me to look at the steering rack, remove the boot on the drivers side and have someone gently and slightly move the steering wheel from side to side, if the output shaft moves up and down the steering rack needs replacing, Look like I will be replacing it shortly.

 

[chadr]

H'mmm not good news - for either of us I suppose. Hope replacing the steering rack resolves your problem. I'll have to have mine checked out soon.

Haven't been driving the truck so much lately, so these issues have been put to the back of my mind.

 

[clivehorridge]

If the vibes are only on braking, I wouldn't rule out a warped disc (rotor) even if they have been replaced. The proper way is with a dial gauge, but I'm sure you could rig up a jig to support a steel straight edge or something similar to detect if they're out of true.

Caliper pistons too can seize or go tight even when recently replaced, it's worth checking them too.

Sorry if you've done all this, just ignore me !

 

[chadr]

I haven't done anything TBH.....other than ignore it for the time being.

Must arrange a visit to Freedom4x4 soon for a bit of investigation, cuppa or two and a natter!

 

[Shayne]

The rack is held with 3 bushes which many on here have replaced and i would look at them first .

The big D is the only one clearly visible but if it looks tired i'm inclined to think the other two do more work .

 

[chadr]

Thanks Shayne - though I had all 3 of my steering rack bushes changes a few years ago. Probably only done 30-40k miles on these new (poly) ones.

TBH it looks more like a brake issue, as recently I've started to notice a slight "grabbing" sensation from them too - not all the time but every now and again.

 

[Shayne]

Sorry Chadr i'm sure you were already aware of the bushes my comment was in response to Valli's post .

 

[Valli]

Yes .... I have changed out the brake disks and pads, all ball joints etc... but the funny thing is the steering vibration started soon after I replaced the disks and pads in the back, I think this is only a coincident. Earlier today I ordered the steering rack from a local supplier so hopefully I will find time to do the installation this weekend.

It was recommended to me to use the poly bushings ...... what do you guy's think about that ? are they to stiff ?