25 replies to this topic

[tofly308]

G'day fellas,

 

Hoping for your help with the Torrie.

 

It's a LX. It's been off the road for a while (engine issues) but on it's first drive back on the road, after about 20 mins driving it developed a steering shake. It initially felt like a wheel balance issue but it quickly developed into a violent shake to the point where I had to stop the car. Get out, check car, all seems ok. Start driving and no steering issues. Maybe 10 or 15mins later, the same thing again. It starts out as a slight shake and increases to a violent shake over about 30seconds.

 

After a few times I realised that if I hit the brakes as it is shaking, that the shaking disappears. Each time I have been at cruising speed of about 100kmh and had been holding the same speed for some time before the shake starts. I have not tried holding a slower speed to see what happens.

 

Before the car came off the road I had the steering rack rebuilt by Wilkinsons suspension but it drove fine on the way home which is a 45min drive. I have jacked the frontend up and checked for any tie rod movement, wheel bearing play and a general check for any excess play. The steering rack mounts are tight as well. I haven't checked the steering rag joint yet. It was replaced at Wilkinsons when they did the rack recon. While off the road, all that happened was engine out for about 5 months. Nothing else was touched on the car in that time.

 

What has me nervous is the fact it disappears when I hit the brakes. If it was a wheel balance issue it should happen consistently at a certain speed and not only after cruising at that speed for a particular time frame.

 

Any help/ideas would be appreciated.

 

If I don't reply in quick time, apologies as I'm on nightshift.

 

Cheers,

Adam

[S pack]

 Caliper dragging slightly causing a rotor to overheat and warp?

Can you try swapping the front and rear wheels around?

[Heath]

I'd try and different set of front wheels to see if you can isolate the problem.

 

I had an aggressive shake in the front end of my Chaser after one of the front calipers seized up and was dragging a bit as Paul suggested above, but I don't remember the exact conditions.

[Rockoz]

Check your wheel bearings again. Did you check them with the wheel on or off?

[rexy]

Wheel nuts are tight?
Caliper bolts tight?
Wheel turn easily and evenly by hand?
Any witness blueing or heat marks on discs or pads?
As above, check tyres for focal bulges and get balanced. When they do this any wheel buckle or other major problem should becone obvious.

[yel327]

Rear wheels out of round? Had this happen on a hatch years ago and it was the rears.

[orangeLJ]

If you lightly apply the brake, does it continue?

[axistr]

G'day Adam,

 

Its not  easy to explain and covering this subject in two or three sentences so I will try an keep it simple.

 

This problem is more common than many people realise. I have seen this problem hundreds of times and is very common in trucks & 4x4 vehicles with solid steer axles, but can also occur in independent front suspension vehicles as you have found out first hand.

 

I referred to this phenomenon as wheel slap because that is basically what it is. If you could see the front wheels when this shake starts both front wheel continue to slap left & right. I have seen some vehicles wheels slap from side to side by up to 6". it looks very scary from the outside to. I have experience its effects first hand on many occasions and one that almost killed me in a truck, so savage that it leapt from one lane to another on a back road almost breaking my keg as it through me out of the seat several times.

  

The shaking generally occurs at speeds over 60-70kph, and when the shaking starts backing off the throttle seems to make the problem worse till the speed is reduced to about half of the initial shaking speed. As you have also mentioned the shake is quickly reduced by applying the brakes, this is due to the front wheels loading up and possibly also toeing the wheels out eliminating the side ways slap. It just takes the right conditions for the slap to occur and that's why you can drive if for half an hour or more before the problem starts. The problem also occurs more often on smother roads rather than really rough roads.    

 

The initial slap is started when one or both wheels deviate from the centre line position either by a bump or the tyres trying to follow a small rut in the road, then the wheels kick to the opposite side and very quickly the violent shake/slap starts.       

 

There are quit a few things that can contribute to this problem or a group of faults that all add up to the end result of wheel slap.

 

Any movement in the steering rack laterally or steering column free play will allow the front wheels to freely move left or right from the steering centre line. (shake starts) out of round tyres can cause the same result causing the wheels to deviate.

 

The five common areas we carried out repairs to eliminate this problem are, listed from most common to least.

 

1) Movement/free play in steering rack: (lateral play).

 

2) Out of round wheel rims or tyres, (at speeds the tyres start to partially hop off the road surface initialising wheel slap): check tyres for lumps & bumps at the tread area, buckled rims and deformation of tyre or band separation, excessive out of balance wheels from inner to outer rim beads. 

 

3) Excessive play in steering column from steering wheel to rack input shaft. (double check steering shaft unis, lock pins, rag joint and steering wheel nut.

 

4) Excessive movement in suspension bushes or components. (also check if you have any wheel bearing movement that   the outer bearing cones aren't loose in the hubs or spinals worn at bearing mountings position). 

5) Wheel alignment: (high caster angles can contribute to the problem but this shouldn't be a problem in a Torrie.

 

I would first get someone to move the steering wheel 6 inches from left to right and check for any free play in any components with the vehicle on the ground.  Next only move the steering wheel from side to side to see how far the steering wheel can be moved before the front wheels start to turn.(very important) 

 

Jack up the car and check for any movement in components and run your hand around the tyre tread area and check for deformation of the tyres case. Spin the front wheels and check for run out at the tyre contact to road area. Checking for either side ways or up and down run out. Putting a block close to the tyre and spin the wheel and check the gap is the easiest.

 

We notice this problem occurred sometimes after a wheel alignment because the vehicle now runs true down the road without scrub or load on the steering that some ruts or bumps can set it off. In most cases just adjusting the play out of the steering box or drag rod was all it needed to eliminate the problem. If that didn't cure the fault we than carried out a on vehicle wheel balance which included run out checks. The two above procedures cured around 75% of the affected vehicles. 

 

Lastly fitting a power steering rack wouldn't go a stray. LOL.   

[tofly308]

Everyone, thanks very much for all the ideas and advice. When I get home next week i'll be running through all these checks.

 

A couple of people have mentioned caliper dragging on disc or similar. And someone asked if I can spin the wheels freely. My front have always been harder to spin by hand than any other vehicle I have owned. It has a hoppers front kit fitted that was on the car when I bought it in 2006. I have previously noticed that with the calipers removed, I can spin the hub/wheels freely but with the caliper mounted it seems a fair bit harder. It was like this well before the shaking issue.

 

I feel like calling wilkinsons suspension and asking if they've encountered this after rebuilding any other racks and/or replacing steering rag joint on the torries. They have a good reputation so I'd rather do some other basic checks before taking it back to them.

 

Cheers again for everyone's input, I will let you know what I find and how it was resolved.

 

Adam

[ls2lxhatch]

It's been off the road for a while (engine issues) but on it's first drive back on the road, after about 20 mins driving it developed a steering shake. It initially felt like a wheel balance issue but it quickly developed into a violent shake to the point where I had to stop the car. Get out, check car, all seems ok. Start driving and no steering issues. Maybe 10 or 15mins later, the same thing again. It starts out as a slight shake and increases to a violent shake over about 30seconds.

 
Like a few have said I would be looking at the brakes first. It sounds like something is overheating and then cooling down then overheating again. If it is the brakes then you should find that it is harder if not impossible to push the car forward once the shake has developed. You may be able to see evidence of overheating on the disk.
 
It wouldn't be the first time that a caliper had developed issues when a car wasn't driven for a couple of months. It also isn't the first time that the calipers used in the Hoppers kit have had problems out of the box.
 

Problem solved, 2 more new calipers later and the wheels are turning free.
Problem was the caliper housing was either not machined deep enough for pistons, so I could just get the calipers over the pads, but there was no clearance for the pistons to release any more so they were constantly on, til you would wear the pads down.
Or the pistons are slightly to long for the caliper body, had everyone stuffed but there going back to PBR.

Edited by ls2lxhatch, 09 April 2016 - 12:40 PM.

[rodomo]

Tyres/wheels/wheel balance is my tip.

[tofly308]

Righto, plenty to check out when I'm home next week.

 

First thing will be a wheel balance and check tyres for run out. Then discs for heat stress and I might just repack my wheel bearings and eliminate bearing play, although I checked for bearing play last week.

 

Then I'll bleed the brakes and also check the caliper pistons have full movement back inside the caliper body. Being quite old and a car that sits around for lengthy periods at a time I might end up replacing the calipers (sounds like they may be the issue going by 'ls2lxhatch' post). I will soon be fitting a double diaphragm booster and later model master cylinder as well so that would eliminate a faulty master.

 

It is pretty tight in the torrie but I will check out the rag coupling to make sure that was fitted correctly.

 

All in all I'm sure out of all the suggestions, the issue will be fixed.

 

Cheers again for all the info fellas.

 

Will keep this updated with how I go.

 

Adam

[axistr]

Adam it is normal to have brake drag on hydraulic disc brakes after you pull up then jack it and try to turn the wheels. This is caused by the contact and drag of the rubber seal to calliper piston. Drum brakes have return springs to pull the shoes off the drums, disc do not. There is generally more drag in multi piston callipers. Its the slight flex in the hub and disc during driving that pushes the pistons slightly further into the calliper to give the pads clearance from the disc. You might have noticed v8 supercar drivers pump the brake pedal down the straight before the next corner, its to push the pads back out closer to the rotors. Hard cornering causing the hub and rotor to load up, pads clearance to rotors increase and you can end up with a long travel brake pedal with reduced brake efficiency. larger diameter rotors tend to push the pads away further. 

 

If you have constant brake drag during driving the pads would start overheating and smoking in less than 5kms. Some mechanics leave wheel bearings loose in believe this will return the pads back better, old wives tail, all it will does is not allow proper contact with the bearing rollers, quickly show signs of wear in hubs and seal, calliper and slides, wheel alignment issues and tyre wear.

 

To check the callipers after jacking push and pull firmly the top and bottom of the front wheels to try and push the pads in a bit and the wheels should spin freely, this should be done before checking wheel bearing play. If your still not sure take the car for a short drive up the street and  use  the park brake for the last stop if possible. If the foot brake hasn't been used jack the car and spin the wheels you should have no drag. 

 

Anything is possible and can't be ruled out, but in my opinion the problem your experiencing isn't initially caused by the brakes.    

[axistr]

You would be surprised, some mechanics just don't know the correct procedures of adjusting wheel bearings. I have even pulled up so called bearing experts that do not know the correct adjustment practice. I have always loaded the bearing to ensure they are seated, back the nut off then nip the adjusting nut till there is no bearing play or movement in the hub. When the bearings get to operating temp the bearing will expand causing slight bearing preload.

 

We had a Timken bearing tech support man come to our workshop giving us a seminar on bearing fitment and diagnostics after a major bearing failure on a truck which failed after 500km. Trying to side step any warranty.( only the second new bearing failure I have had in 30 years) The tech instructor told my staff that all bearing were not designed to be tightened to preload the bearings and must be checked with a dial indicator to ensure they had .015-.035" movement in the hub or shaft. Obviously this tech support person has never done diff or gearbox bearing replacements. I asked why do Timken make wheel bearing kits for various O.E manufactures which includes a machined bearing spacer that sets specific preload on the bearings. He couldn't answer the question and quickly wrapped up the seminar. Just for the record Timken paid for the $8,000.00 damages to the truck.  

[S pack]

I don't know what your definition of tight is but you should NEVER do up bearings tight.
As you do up the nut, you move the rotor to ensure the bearings have seated, then as you said, the 1 finger spanner trick and call it good.

And if a slot in the castellated nut doesn't align with the split pin hole in the stub then back the nut off until the closest slot aligns so the split pin can be installed.

[76lxhatch]

I don't know what your definition of tight is but you should NEVER do up bearings tight.

 

Unless you have a preload spacer, as Axistr mentioned (and as used on pretty well all diff pinions and carriers). Only bearing assemblies without have play

[EunUCh]

Not sure if it has been mentioned yet ? could a buggered rack end bush (passenger side , the pressed in one) cause a similar 

fault ? , depends what was fitted during the rack reco. but some of the shit that the original styles are replaced with are not what the

originals are supposed to be replaced with...just a thought for what it's worth.

 

i think you would need some serious wheel bearing slop to cause the fault described ?