Judicious application of a hefty right foot usually. You need decent leather boots on rather than trainers or the like and then you just kick the shit out of one side of the tyre, then the other until it decides to part company with the hub. All done from the outward facing side of the tyre btw not from the back. It's the twisting force between the edge of the tyre and the hub as you kick the tyre that starts to loosen the corrosion. You can't use metal hammers or you'll damage the rim and rubber mallets are useless anyway. The most force you can apply without damaging anything turns out to be with your foot.
I recently struggled for about half an hour with a rear wheel on my Focus which hadn't been off for at least six years until finally phoning a mate for advice and he told me to put bigger boots on and kick it harder. Up till then I'd tried swinging at it from behind with lumps of wood, hammering on lumps of wood with a 4lb lump hammer, levering at it with a crowbar and kicking it with trainers on to no good effect other than hurting my foot. A good kicking with my hiking boots on had it off fairly smartly. As soon as you see it move even 1mm or so you can generally then grab it and wiggle it free.
In the end I did go elsewhere, but even though I was legal, I wanted to avoid the hassle of being pulled in an unregistered car (insured on the VIN) and having to try and persuade them that all was legit, hence wanting to use the nearest place.
Took one of my Rover 45's down to the garage that the ex Rover foreman had set up after they went bust, He put a scale on the floor and pushed the car over it and declared that it was OK. I have not seen one of these scales in more than 40 years, but he was right, the tracking was perfet, except for a slight steering wheel mis- alignment that is not big enough to worry about yet.
He can do 4 wheel alignment, but this was much quicker for him.
With R&P steering if the wheel ends up off centre the tracking isn't correctly done - the geometry will vary as the wheels turn. Unless the steering wheel has been moved on its splines.
Can you expand on that, please? I assume that is because the steering geometry varies from neutral to off set when the steering wheel turns fron neutral, but that the RAP will be in neutral if the steering wheel does not match it, or have I got that horribly wrong?
The rack forms part of the link between the wheels and has balljoints on either end. If it were part of a rigid link - as on cars with a steering box - it wouldn't make any difference to the geometry if off centre. But because it isn't, the geometry won't be accurate when the suspension moves or the wheels turn. May not in practice be a big error, but best avoided. But it requires more accurate equipment - and skill - than the likes of Kwikfit possess.
*If* the tracking is correct in the straight ahead on a level surface, adjusting each track rod end by the same amount to bring the wheel straight should do it. But best to have it checked again afterwards.
Ummm no it won't. The straight-ahead position of the steering wheel has no effect on Ackermann steering geometry which is created by the angles of the steering pivots and tie rod.
formatting link
with tracking set correctly you move the steering wheel slightly off centre and then recheck the tracking. The tie rod ends will now be too long at one side and too short at the other. So you undo the locking nuts and adjust everything until the wheels are straight again. All you've actually changed is to lose a little steering lock on one side and gain a little on the other. The steering geometry hasn't altered. The total length of the tie rod (rack) is still the same, the steering pivot angles are still the same, the wheels are still pointing straight, the steering wheel and pinion have just moved relative to the rack is all.
A rack and pinion system has a completely linear mode of operation. A little logical thought ought to make it apparent that it can't be the movement of the pinion relative to the rack or their initial starting positions that creates a non-linear steering output on opposite sides of the car which indeed is created solely by the movement of the rack relative to the steering pivots.
Unless the
Again utterly irrelevant other than you lose steering lock on one side and gain it on the other. I once had a Fiesta XR2 which I ran for years until it gradually dawned on me that if I turned into my driveway from the usual direction I approached the house in I had no difficulty but if I came back home from the other direction which was pretty rare I struggled to get enough steering lock on to make the turn. In normal driving there was no other apparent fault or difficulty. After pondering this for a while I started checking everything and finally found that from the straight ahead position I had a lot less steering lock on one side than the other. In fact after marking the steering wheel with a bit of masking tape and counting the turns either way to the stop I calculated that I had one third of a turn more on one side than the other which was a massive error. Turns out that at some time in the past the steering wheel had been taken off and moved round a notch on the steering column which had a hexagonal fitting rather than a spline on this model. So I'd lost a sixth of a turn on one side and gained a sixth on the other.
Checking the tie rod ends one side was indeed wound almost fully in and the other side almost fully out. God knows how anyone had managed to screw this up so badly and not realise. The garage I'd got the car from was run by complete numpties though so that probably explains it. Anyway, with the steering wheel back in the right place I had to make a massive tie rod end correction and finally got everything back as it should have been. However at no time was there any unusual tyre wear or strange steering or handling behaviour. The steering wheel position simply makes no difference to this.
BTW it should also be apparent from the above that just because the car tracks straight and the steering wheel is in the right position while it's doing that is no indication that everything is correct. Before checking the tracking you need to check the turns lock to lock either side of the straight up position. If this is the same both ways then the steering wheel is on correctly and the rack is properly centred. If not then the steering wheel needs to be moved on its spline before the track rod ends are adjusted to set the tracking.
On modern cars the steering geometry changes by design. I can't see how the steering rack makes any difference though. Its controlled by the top and bottom bearings of the hub and the direction the wheel is facing, not how much rack is hanging out of each side. What you do get is different turning circles on LH and RH corners but even that doesn't effect normal driving.
That's not quite true! If the links from the ends of the rack to the steering arms on the hubs are of unequal length, there is a strong likelihood of bump steer. When correcty adusted, those links should shadow the wishbones - allowing the wheel the move up and down without steering. But if you make one too long and the other too short, that no longer applies.
I did also say the rack had to be central too. Which it will usually be from the factory with the wheel in the straight ahead postion.
That might be true if the ball joints on the end of the rack were exactly in line with the suspension pivots. But move it to one side or the other and the geometry changes with suspension movement, as you're moving that pivot point.
Sorry but you're wrong.
You're forgetting that the rack isn't rigidly connected to the track rods. If it were you'd be correct.
Think again of the action on the road wheel position as the suspension moves up and down. The rack cannot move up and down with it so there is a pivot at each end of the rack and of course the track rod end. If everything else remains static the wheel will turn in slightly at either end of the travel under the influence of the track rod. Using strut suspension as an example where the wheel moves up and down in a straight line. If you alter the length of that tie rod the effect will be more or less apparent - depending on whether it is longer or shorter.
Just how much it matters in practice varies by suspension design.
Yup. I'd also expect heavier tyre wear if things are miles out.
It is actually quite critical on my SD1. The rack on that has a centre finder - an indent in the rack that a bolt fits into to lock it in the central position. No need for that if it weren't important.
The effect of a slightly off centre steering wheel on the relative lengths of the tie rod ends at each side of the car is not large enough to make any significant difference to bump steer or any other steering input. Cars simply aren't made to that level of accuracy. I bet if you take a tape measure to each side of your car and measure the wheelbase from front to rear wheel centres you'll find it's nowhere near the same. 1/4" inch out is not unusual and if the wheels aren't located to within a fraction of a mm anyway then a similar sized error in the lengths of bits of steering rack isn't going to affect them either. Similarly camber and caster can vary each side, both of which affect track rod end settings.
If the suspension moves up on one side and not the other it changes the track slightly. It does this under normal conditions. I doubt if it will be out of spec even if you do move the rack ends over by an inch or so. You get a similar movement when you load the car but on both sides.
You need equal length tie rods from the rack ends to the hub links. Otherwise wheels will slightly turn more one way than the other when the suspension rides a bump.
HOWEVER a good thump can actually move the WHOLE RACK sideways. That makes a nonsense of the statement here:If you are doing the job properly, the first thing to do is line up the rack again.
Yuyp. I bought a second hand XJS that had been in a smash..and fixed. Well I drove it for two years through to its SECOND MOT after I bought it before they discovered that the actual kingpin was bent, and this had been taken out with extremely offset track rods and a few other adjustments. A fast corner on an undulating surface had it squirreling like mad! You get the same with a lot of McPherson strut type suspension layouts as standard.
When I used to drive Spridgets madly, and Spitfires, I could always tell when there was any unevenness or play - well below MOT failure levels - anywhere in the front suspension. You can feel it in a double wishbone system. McPerson's you cant, because they are basically crap anyway..there is more wheel lateral movement from bump steer and it totally swamps the variable tie rod issues.
Indeed. With an unequal length wishbone suspension it also - by design - changes the camber angle - to try to keep the outer wheel more upright when the car rolls when cornering. But what it *shouldn't* do - but will do if the tie rods are the wrong length - is *steer* as the suspension moves up and down.
You can try a little exercise if you have a convenient car to play with. It's been a long time since I last messed about with tracking but from memory let's say the dangly bits either side of the rack that move up and down with the suspension are about 1 foot in length. What we're talking about here is differences in the length either side created by a steering wheel slightly off-centre amounting to the odd mm or two in maybe 300 plus mm. It simply isn't material in how those dangly bits follow the hub as the tyre moves up and down or indeed how the rack moves each wheel in a turn to create Ackermann steering. I bet if you measure any undamaged car that's got its tracking set as spot on as you can get it you'll still find the distance from the track rod end ball joint to the rack end pivot point is nothing like the same on both sides. Production tolerances in chassis dimensions, rack dimensions, mounting points, camber on each side, caster on each side, wheelbase on each side etc etc add up to affect that dimension and track rod ends are made with enough thread length in them to take up those differences.
Like I said with my Fiesta, even the most extreme steering wheel positional error you could imagine, which in fact had used up nearly all the track rod end adjustment on each side, so about 3/4 of an inch or so, still made no apparent or effective difference to how the car drove or how the tyres wore. One sixth of a turn, which was the error in the steering wheel position, is
60 degrees or effectively a steering wheel that instead of pointing to 12 o'clock would actually have pointed to 2 o'clock if it hadn't been moved on its mounting. That's way bigger than any error you'd get from tracking places that don't hold the steering wheel perfectly level when they set things up. At worst they might be an inch or two out at the rim.
Talking on a theoretical level and what actually matters in practice are not even closely related. The average mass production suspension system doesn't have geometry that generates either perfect Ackermann steering or absence of bump steer or scrub anyway. None of that really matters as long as the wheels are correctly tracked in the straight ahead position regardless of where the steering wheel sits. Tyre wear, or at least the vast majority of it, is caused by errors in that straight ahead alignment not errors in Ackermann geometry, bump steer, scrub or any other fault of production tolerances or design. The next biggest culprit is errors in camber and if you go to one of those fancy tracking places you'll get a print out of what the camber is on each side. Not even remotely the same on both wheels I can guarantee you. Cars just aren't built that accurately and they have too much play in rubber suspension bushes to make close tolerances achievable anyway.
On race cars you might strive for higher standards after you've eliminated the play in bushes and linkages but on road cars you're just pissing in the wind to worry about steering wheel position as long as the actual tracking is correctly set.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.