VZ V6 Sedan Wheel Castor Adjustment

[vc commodore]

I think they look like the standard Holden bushes. Pic 1 is from the Holden manual & Pic 2 is from the Nolathane website. The Holden mounting plate has 4 mounting points & the Nolathane ones have 6. Or are these perhaps older style Nolathane bushes?


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The ones fitted to the car are nolathane branded ones...The nolathane branded bushes have extra washers (3 per side extra), of 3 differing thicknesses, which are placed in a particular position to move the wheel backwards or forwards, depending on the caster readings. Factory bushes don't have the extra washers to allow this adjustment

 

[Growley]

Seeing you can fit 4 fingers on the left and 3 on the right, this indicates to me, the caster is fine....this is providing you placed the fingers between the rear of the wheel and the mudguard.

If you have an alignment report, post this up, as it might be a camber issue causing the pull.

Another thing to check is tyre pressure....Are they even? You could also swap the front tyres left to right and see if that solves the issue

Finger placement was at 3pm or 9pm depending on which side was being tested just above the mudguard. I don't have an alignment report & didn't realise I could ask for one. Tomorrow I'll check tyre pressure, whether or not both sides have the same number of washers on the Nolathane bushes & swap the tyres around. Thanks for everybodys help thus far.

 

[vc commodore]

Finger placement was at 3pm or 9pm depending on which side was being tested just above the mudguard. I don't have an alignment report & didn't realise I could ask for one. Tomorrow I'll check tyre pressure, whether or not both sides have the same number of washers on the Nolathane bushes & swap the tyres around. Thanks for everybodys help thus far.

Little bit of insite into caster.....Caster is the angle between the top balljoint or it's position (as your car doesn't have one) and the lower balljoint, looking front to rear....The left front caster angle is larger,(further forward) do counter act the road camber (angle), as roads slope to the left, to drain water into the gutter when it rains.

You have proved that your left front wheel is further forward than your right, using the finger test (ancient, but effective), so the washer placement is obviously correct, otherwise you'd fit more fingers in the right.

So this can only leave 2 things...The camber or tyre wear....

Tyre wear.....If an edge on 1 tyre is worn more than the opposing tyre, it will cause the car to go that direction....It's similar to rolling a ball.....Roll it on a flat surface, it'll go straight....roll it on an angled surface, it'll roll down the angle....The exact same principal applies to a flat tyre....Hence why I suggested tyre pressure and tyre swapping.

Once you have done the tyre swap and pressure check, let us know how you have faired and if you still have an issue, we will look at the camber

 

[diysv6]

I replaced my oil filled front z bar bushes with a Nolathane kit.
I have attached the excel sheet which describes where the thick, medium and thin washers fit on the driver and passengers' side.
Maybe this can help when you check what washer is where.


View attachment Z Bar Bush 48166 Nolathane Caster Washer kit.pdf

 

[Immortality]

Interesting.

Wasn't it typical to just use a little more toe in on the passenger side to account for the camber on the road surface?

 

[vc commodore]

I replaced my oil filled front z bar bushes with a Nolathane kit.
I have attached the excel sheet which describes where the thick, medium and thin washers fit on the driver and passengers' side.
Maybe this can help when you check what washer is where.

This would be a rough guide.....To get it correct fairly quickly, you need a before caster reading, so you know what thickness washer goes where.....You can "play" around, placing them in various positions to get them right, without the before caster reading but it can take a while to get it correct.....Then you have the issue of the toe being incorrect, as caster does effect the toe reading.

 

[vc commodore]

Interesting.

Wasn't it typical to just use a little more toe in on the passenger side to account for the camber on the road surface?

Nope.....You can add a little more toe, to help prevent premature tyre wear, when the camber is a little on the excessive side. Caster is one of the main things that help a car drive straight

 

[Immortality]

Caster helps the wheels self centre, I get that and modern cars run a lot more caster but I'm fairly sure my old Commodore (1983 model) has stuff all caster with zero adjustment, stuff all camber correction which only really leaves the toe adjustment?

I was just thinking, he said his measurements were 3 and 4 fat fingers, I would take a fat finger at 10-12mm, the factory setting is +4mm which according to the PDF above equates to about + 0.5##° caster on the LH side. If indeed his fat finger is 10-12mm than we are looking at a difference of about +1° to +1.5° caster.

I know for certain that after fitting new bushes on the family wagon (VX Calais) the difference was about 1/2 a finger.

 

[vc commodore]

Caster helps the wheels self centre, I get that and modern cars run a lot more caster but I'm fairly sure my old Commodore (1983 model) has stuff all caster with zero adjustment, stuff all camber correction which only really leaves the toe adjustment?

I was just thinking, he said his measurements were 3 and 4 fat fingers, I would take a fat finger at 10-12mm, the factory setting is +4mm which according to the PDF above equates to about + 0.5##° caster on the LH side. If indeed his fat finger is 10-12mm than we are looking at a difference of about +1° to +1.5° caster.

I know for certain that after fitting new bushes on the family wagon (VX Calais) the difference was about 1/2 a finger.

Part of the reason modern cars run high caster numbers, is due to power steering being a factory fitament....The higher the caster, the harder it is to steer at lower speeds.

Earlier commodores (VB through to VP) had camber and caster adjustment....You turned the strut.....the strut top was offset.....However you couldn't just adjust one, without it effecting the other. Unfortunately not too many people knew this, or could be bothered turning the strut tops, to get a car driving straight, or standing wheels up. Or in laymans terms, stuff the customer, we'll get them reaching for their wallet.

I do know, K-mac supply aftermarket strut tops, which can be used to fine tune either camber or caster. Most lazy buggers will try and flog these off to the unsuspecting person, to "fix" there car, because they can't be bothered helping the customer...The only place these really have is for a race track, where caster and camber adjustment is imperative

The radius rod on the earlier commodores were slightly different, left to right....the left had more of a Z, when compared to the right....This was to give it more caster on the left.

Toe.....This is the adjustment to shorten or lengthen the distance between the front wheels, when looking at the 9 o'clock and 3 o'clock positions....so it can't be used to get a car driving straight, without effecting tyre life.

 

[Immortality]

Yeah, I know about turning the strut top, still only very limited adjustment really.

Can't say I ever noticed a difference between the radius rods either and I have had em off laying next to each other at some stage. Might have to take a closer look next time I have an early girl apart.