P38 DIY wheel alignment.

[PeterH]

I've been noticing a slight pull to the left while driving, it's not bad, but I would like to get it sorted.
On my classic Rangie I had a length of wood with a screw in both ends, was able to measure the toe in/out by placing it at front and rear of the rims.
Is this possible on the P38 as well?
The only adjustment is toe in/out, and is adjusted on the track rod.
Has anyone used this method successfully?
Or would I be better off just going to a proper place to have it done?
I've also seen laser kits on ebay that might be worth looking into, would be interested to hear if anyone has tried these.
Thanks, Pete.

[d2dave]

Toe in/out has no effect on a car pulling. This is caused by caster which in your case is not adjustable.

I would suggest that your pulling might be caused by tyres. Try swapping left to right.

Have you also tested it on a very flat road as a lot of roads have a camber on them, which will cause a car to want to veer left.

[PeterH]

Thanks Dave, interesting, didn't know pulling was not toe in/out.
I had the same thought about the angle of the road surface, but it does seem to do it on most roads. I'll try driving on a flat surface tomorrow and see what that does.
I'll try swapping the wheels over, does changing the direction of the tyre rotation have any ill effect on the tyres?

[d2dave]

Some tyres are directional. They usually have an arrow or something to determine direction.

I have never seen these on a 4x4 though.

The reason toe in/out won't cause pulling is that the toe is always equal on both wheels.

You can adjust just one side only but when you drive they will both point straight ahead, just your steering wheel will be off centre.

Whereas on a car that has adjustable caster, each side can be individually adjusted to different settings.

In the old days on Falcons sometimes after an alignment it might still pull a tad. I would take a spanner on the test drive and it was easy to adjust caster on the side of the road.

[poleonpom]

Could be worn ball joints. Mine is doing the same and has also become a little vague in the steering dept. A good poke around revealed worn ball joints.

[PeterH]

The upper ball joints were replaced a couple of years ago, the lower ones were fine, but I'll check them on the weekend, thanks for the suggestion poleonpom.

[TheTree]

Mate

You can pretty easily check your toe in/out with the chalk and string method there are plenty of videos on how to do it.

But it won't stop drifting or pulling to one side as has been said

Steve

[Hoges]

Hi Pete it's caster issue. Normally if you drive in the rh lane on a freeway which drains to the median strip the road camber will normally cause the vehicle to slightly veer to the right..

Re. Laser measuring devices for toe-in.... i have used a TrackAce. It's very good
Cheers

[blindin]

Have you checked the tyre pressures? As mentioned, there are so many things which can cause the steering to pull. It could even be a flexi brake hose starting to collapse and hold the brake on slightly. If your tyres are wearing even then your alignment is probably ok. I haven't been on the tools for years now, but have done many alignments, with lots of different methods, including setting up race cars, now a days I just do mine by eye, I know it is not accurate, but I haven't had a set of tyres wear for quiet a few years. I would be checking over every thing, no matter how silly it may seem if you are concerned about it. Try to see if it pulls on certain roads, under acceleration, if it drifts the other way when you ease off. You may be able to narrow down your search.

[RR P38]

The link arm doesnt need very much free play to cause a problem.
Nor does free play on the steering arm off the power steer unit.
Minimal movement has caused me to feel the RR is not tracking well.
It is actually fairly hard to see the slop its much easier to feel it as some one rocks the steering wheel for you.
The link arm seems to be a hit and miss replacement I have had less than 10,000km out of some and others have lasted 80,000km......variable quality of parts?

[PeterH]

Thanks for all the replies, gives me some good places to start looking.
I've checked the front tyre pressures and they are exactly the same, 30 psi each side.
I swapped the front wheels over and it made no difference.
As far as I can see there is no unusual wear in the front tyres.
I noticed when I brake, it seems to pull left a bit harder, I can watch the steering wheel move to the left while braking.
Going over a speed hump, I noticed a slight movement in the steering, might be a bit of slop in the steering box.
Would it be worth tightening the steering box slightly?
I'll have a look underneath and see if I can spot any movement in the steering components while someone moves the steering wheel for me.
As I said, it's not very bad, but it is annoying, I'd like to get it sorted.
Will keep you posted!
Thanks, Pete.

[wayneg]

Going over a speed hump, I noticed a slight movement in the steering, might be a bit of slop in the steering box.
Thanks, Pete.
My previous P38 had a tendency to wander, cured but tightening the allen bolt in the top of the steering box 1/3 turn

[TheTree]

The steering box can be adjusted and I have done mine to great effect.

I couldn't find it in RAVE but I knew what do to from my series one steering box :cool:

Release the 17mm lock nut and tighten the Allen key set screw until you just feel resistance, then while holding the set screw in place, tighten the lock nut.

Do not overtighten the set screw just tigthen it enough to take up any slack

Steve

[TheTree]

Mate

Sounds as if you have a couple of small issues; pulling the left when braking indicates a brake issue ... pads on one side maybe?

Steve

[PeterH]

Thanks Steve, I've never touched the steering box before, will follow your instructions.
I have done a bit of work on the brakes, new rotors 6 months ago, pads are all in good shape, just changed all 6 brake hoses and 2 full bleeds.
I checked and lubricated all the caliper pins last time, so while brakes are a possibility, the pull is always there, just more noticeable while braking.
I just drove on the right side of a road with a steep angle to the right and it did want to go right, which is causing me to think it's a steering component, I think you might on the money with the steering box tightening.
I'll have a crack at the steering box first, and also see if I can spot any movement under there.
Thanks again!

[d2dave]

A loose steering box should not cause a car to pull, just wander.

If you had a car that didn't pull, put it on a very flat area and completely disconnected the steering box, the car should still drive straight, just you would not be able to steer it.

[TheTree]

A loose steering box should not cause a car to pull, just wander.

If you had a car that didn't pull, put it on a very flat area and completely disconnected the steering box, the car should still drive straight, just you would not be able to steer it.

This is true, the issue it fixed on mine was the vibration death rattle!

Still good to check it's adjusted ok though

Steve

[blindin]

As above, steering box won't pull to one side or the other, just sloppy steering.
Have you checked your suspension heights? If it is not level it will pull, that would also be noticeable on braking too.

[TheTree]

T the pull is always there, just more noticeable while braking.


Since it pulls all the time, it is something in the steering/suspension geometry for sure

It may be worth taking it to a wheel alignment shop to get it checked. Whilst only the toe in is adjustable, they can give you a full report on all of the alignment settings

What shape are your front end suspension bushes in?

SuperPro make a set of correction bushes

Range Rover P38 Front Radius ARM 'Pull Correction' Bush KIT Superpro | eBay (http://www.ebay.com.au/itm/Range-Rover-P38-Front-Radius-Arm-Pull-Correction-Bush-Kit-SuperPro-/231382802780)

Steve

[RR P38]

30 PSI is very low pressure. (For the road)
I would only run that if I wanted an extra soft ride while ferrying a granny about.
On the road 36 minimum and mostly for highway I will run 38-40 PSI
On a track with a reasonable surface I would run 30.

What sort of tires are you using?
Same front and rear?
Standard size?


Thanks for all the replies, gives me some good places to start looking.
I've checked the front tyre pressures and they are exactly the same, 30 psi each side.
I swapped the front wheels over and it made no difference.
As far as I can see there is no unusual wear in the front tyres.
I noticed when I brake, it seems to pull left a bit harder, I can watch the steering wheel move to the left while braking.
Going over a speed hump, I noticed a slight movement in the steering, might be a bit of slop in the steering box.
Would it be worth tightening the steering box slightly?
I'll have a look underneath and see if I can spot any movement in the steering components while someone moves the steering wheel for me.
As I said, it's not very bad, but it is annoying, I'd like to get it sorted.
Will keep you posted!
Thanks, Pete.

[TheTree]

I run factory pressures in mine 28 front and 38 rear

It actually states in RAVE that over inflated tyres can cause steering issues

Steve

[PeterH]

I have the same tyres all round, Michelin standard 255/65/R16, they are all fairly new and in good shape.
I always thought 28 seemed low in the front too, but as Steve already pointed out, that is the factory recommended pressures, so that's why I have them (close to) that pressure.

[d2dave]

I have the same tyres all round, Michelin standard 255/65/R16, they are all fairly new and in good shape.
I always thought 28 seemed low in the front too, but as Steve already pointed out, that is the factory recommended pressures, so that's why I have them (close to) that pressure.

A lot of car manufactures have a recommended pressure which is lower than what tyre manufactures would like.

This lower pressure is ok, just not optimum. It is a compromise to try and get the softest most comfortable ride.

[TheTree]

In the longer term the tyre wear pattern will show you if your inflation pressures are correct.

Steve

[PeterH]

Steve I've never touched the radius arm bushes, they are probably the original ones, I'd guess they would be in need of replacement for sure.
I tightened the steering box slightly, while it is definitely tighter steering feel, it is still doing the same thing.
I might have to check the calibration of the air springs, maybe do the radius arm bushes as well.

[TheTree]

Checking the spring calibration sounds like an excellent idea!

Steve

[RR P38]

They are the best tires for a P38 as far as im concerned.
I have had 4 maybe 5 sets of them over the years try 38 PSI all round, If you are doing motorways a lot 40 is a good number.
I have over 350,000km on my P38 all the bushes in the front end that I replaced (original) where not too bad as far as I could tell.


I have the same tyres all round, Michelin standard 255/65/R16, they are all fairly new and in good shape.
I always thought 28 seemed low in the front too, but as Steve already pointed out, that is the factory recommended pressures, so that's why I have them (close to) that pressure.

[TheTree]

The factory pressures would have been arrived at after many 1000's of Kms of testing by LR, I doubt the tyre manufacturers did much testing on the actual vehicle.

They are a compromise between comfort, handling, wear and safety.

Over inflated tyres are less safe and do not handle as well because less of the tyre is in contact with the road so personally I stick close to what LR specifies

Steve

[blindin]

Hi Steve.
Regarding the pressures, there has been extensive testing done on tyres, and lots of good information readily available regarding tyres & pressures. I also work in the driver training industry. A tyre with a slightly higher pressure would be safer compared to one which is either at, or below the manufactures recommendation, of course there is lots of different situations, and this may be adjusted depending on that. You are correct in the fact that land rover would have done lots of testing, and the pressure they have come up with is a minimum safe cold pressure, for slow, and short trips without any additional weight. As mentioned, there is lots of info around, I am happy to give a few reasons more, but thought I would just mention it. Not saying that land rover is wrong, I'm just saying it is a minimum cold pressure.

[TheTree]

More than happy to hear the reasons for sure.

Also i usually run just above factory pressures and of course I air down when offroad or even more on sand , and add some pressure, especially to the rears, if I am going on a long trip carrying a load.

Not convinced by the tyre guy who told me to run 40PSI all around though !

Steve

[Hoges]

there's a big difference between highway-biased tyres and D94 A/Ts. I previously had cooper H/Ts and ran them at the recommended 28/38. The Dueler D94s being light truck A/Ts have very different characteristics and need an extra 6psi in the front (as I found out one afternoon on the Macquarie Pass albeit at less than 40km/hr).
(I used ride up/down "the Pass" on a pushbike in the early 60s about 5-6 times a year;))

[benji]

My pressures mainly depend on load. Normally 32/40. But 35/45 on trips. When towing a car etc I'll put the back up to 60, as I do prefer a bit of weight on the back of the car.

Sent from my GT-I9305T using AULRO mobile app

[blindin]

Most tyre failure is caused by heat, which in turn is caused by the flex of the tyre, the lower the pressure, the more flex. As already mentioned, as more weight is added, and there fore more flex. Also, the factory pressure where probably worked out in a cooler country, and despite most people understanding, as the temperature rises, the pressure should increase too, this is to counter the additional heat. Most tyres have maybe about 10 psi range where they will keep the optimum footprint on the road. tyres which drop below this by only a couple of psi are now starting to get dangerous. less control of the car, less braking efficiency, high chance of failure, and of course less fuel efficient. If you are over inflated, the tyre will start being less effective, but at a much slower rate. The chance of the tyre failing will be minimal, ( these things take a huge amount of pressure before they are at any damage of blowing out from pressure, a lot more than any compressor can give you ) and also under braking, the weight increase to the front tyres will increase by a huge amount, and then the extra pressure will be of benefit. Now thinking about this, and then how and when we check them, or inflate. most people will pump them up when they are warm, so already giving approx 4 psi higher reading any way, then the non calibrated gauges, these could also be out, and if we weren't checking them frequently, or we were to pick up a slow leak. These are just some reasons, not trying to be a smart arse, but this is some stuff I talk about quiet often. There is so much info around now, compared to 10 years ago, as mentioned, there is never a one size fits all pressure, and really depends on the situation. Oh, also, if the tyre size has been changed, then the factory pressure mean very little, also if they are a different tyre than what they came out with. An l/t tyre will warm up quicker, and higher as it is thicker, so therefore will require a higher pressure. I run mine between 40-50 psi.

[deano2469]

i ran 32 psi all round for a year or so after i bought my truck. Three out of the four tyres developed a bubble under the skin and made for a bumpy ride.They were Hancook tyres, and also appeared to wear the edges out first. My brother who was a tyre fitter has advised me to run 40 to 45 psi all round. As such the four new tyres have all been wearing even and no dramas. I drive highway 90 % of the time and asleep the other ten...no not really but steers and turns well at these pressures.

[davidsonsm]

When doing a defensive driving course they reinforced the benefits of running higher pressures i.e. the 40 to 45 psi range.

[TheTree]

So do people run the higher pressures all round or do they keep the 10PSI difference that LR specify?

Steve

[d2dave]

I personally think 10 is a bit high, although as stated it is ok. I go around +6 for the rear and +4 for the front.