Adjustable Castor Bushes

[blind_elk]

I used to have the Whiteline adjustable castor bushes installed in my R32 GTS4. I also had the camber kit.

I had a strange combo, where I had too much castor but not enough camber on one side. As the camber was increased, so did the castor, causing a larger mis-match between L & R. I've since replaced the bushes with straight swap Urethane bushes.

The real question here is:

How do you adjust the castor bushes? It seems that it's necessary to pull the rods out to make any sort of adjustment. Very labour (and hip-pocket) intensive.

[Sydneykid]

I used to have the Whiteline adjustable castor bushes installed in my R32 GTS4. I also had the camber kit.

I had a strange combo, where I had too much castor but not enough camber on one side. As the camber was increased, so did the castor, causing a larger mis-match between L & R. I've since replaced the bushes with straight swap Urethane bushes.

The real question here is:

How do you adjust the castor bushes? It seems that it's necessary to pull the rods out to make any sort of adjustment. Very labour (and hip-pocket) intensive.

<{POST_SNAPBACK}>

The crush tubes in the polyurethane buhes have offset holes. So you just undo the front radius rod retaining bolt and rotate the crush tube to adjust the caster. It actually takes longer to type it than it does to do it.

First put the car on the aligner and ascertain the adjustment required. From memory the adjustment is 1.5 degrees, so half a turn is 0.75 degrees, 1/4 of a turn is 0.37 degrees etc. Remove the bolt, turn the crush tube the desired amount, replace the bolt, check result. Any decent wheel aligner will get it spot on in one go.

cheers

[blind_elk]

I was hoping you'd know the answer, SK.

But from memory, the crush tube is inside the chassis mount, and the rods are difficult to extract from that area without undoing everything. Apart from the fact that the bushes are quite a tight fit everywhere (crush tube in bush and bush in housing).

[Beer Baron]

even taking out a whole castor rod and replacing it is only a 10 minute job. that's on the floor in the garage. if it's in a workshop, make that a 5 minute job each side.

[Sydneykid]

I was hoping you'd know the answer, SK.

But from memory, the crush tube is inside the chassis mount, and the rods are difficult to extract from that area without undoing everything. Apart from the fact that the bushes are quite a tight fit everywhere (crush tube in bush and bush in housing).

<{POST_SNAPBACK}>

Yep, the bush in the housing is a tight fit, but the crush tube rotates fairly eaily in the bush. My experience has been 99 times out of a 100 I just rotate the crush tube for max caster and bolt it up. Usually I don't have to adjust it after that, only for bent chassis and then only on one side.

cheers

[blind_elk]

OK, thanks for that. I might give them another go then. Although +/- 0.75 deg castor adjustment isn't such a lot, is it?

[Sydneykid]

OK, thanks for that. I might give them another go then. Although +/- 0.75 deg castor adjustment isn't such a lot, is it?

<{POST_SNAPBACK}>

That's a static measurement, the dynamic caster is much more noticeable as the polyurehane bushes don't deform as easily as worn out standard bushes. So it makes a noticeable difference on the move. Plus you can't go too far as the tyres start to rub on lock.

cheers

[Baz]

Don't mean to hijact thread by just a quick question. Adjustable castor bushes are a cheaper alternative to the replacement adjustable lower control arms. Do these direct replacement's offer much more adjustability than the bushes I am guessing? Is it worth spending the extra buck for one?

[satanic]

So adjustable castor rod and lower control arms are the same thing?

Also, would you guys reccomend putting in adjustable castor rods at home if it only takes 10minutes? How much chance is there that something could go wrong?

[blind_elk]

So adjustable castor rod and lower control arms are the same thing?

No. Castor rods control fore / aft movement of the suspension - they generally align with the length of the car. Lower control arms connect the suspension / hub to the cross-member - they are perpendicular to the length of the car.

Also, would you guys reccomend putting in adjustable castor rods at home if it only takes 10minutes?  How much chance is there that something could go wrong?

<{POST_SNAPBACK}>

Not recommended. The positioning of the offset affects wheel alignment, therefore handling. You will need to have the car hooked up on an alignment machine so that the bushes are adjusted correctly / evenly.

Edit - The other problem is you need a press to remove the rubber bush and fit the new urethane bushes.

[Duncan]

Or put them in at home and drive straight to the alignment shop.

A car with random toe out is *extremely* unstable to drive.

Baz I've never tried the control arms, but bushes can give you up to about 5.5o of caster which is a fair bit

[satanic]

Yeah I was thinking I would replace them with adjustables and drive straight to the wheel alignment. Problem is that I need to get my hands on a press (if what you are saying is correct)

Will give it some thought, sounds easy enough and the wheel alignment place is 5 minutes away

[Nebuchernezzer]

Edit - The other problem is you need a press to remove the rubber bush and fit the new urethane bushes.

I've generally just used a vice on most urethane bushes before and hand pressure on some that are pressed in from both sides (which i presume these aren't).

Did a set of control arms from a R31 the other day and it's not real hard to do at home.

By the way how much are you getting urethane bushes for? I looked at Noltec and Whiteline ones for a mate and they are either as expensive or more expensive then a bolt on rose jointed castor rod.

[Sydneykid]

Yeah I was thinking I would replace them with adjustables and drive straight to the wheel alignment.  Problem is that I need to get my hands on a press (if what you are saying is correct)

Will give it some thought, sounds easy enough and the wheel alignment place is 5 minutes away

<{POST_SNAPBACK}>

If you are doing the aadjustable caster bushes versus adjustable arm think, have a read of this thread, it should answer your questions;

http://www.skylinesaustralia.com/forums/in...showtopic=91064

cheers

[blind_elk]

Just had a look at the kit again - the steel offset rods are a very tight fit in the bush (although I haven't greased them up or anything). Should they be that tight (probably where I got the idea that they would be difficult to adjust).

And I still can't figure how you would make an adjustment with the whole bush assembly wedged inside the chassis mount.

[Duncan]

Ahh that bit is easy, the hole is not in the middle of the metal tube. So as you turn the bolt you move where the middle of the bush is relative to the chasis

If the hole is in the middle of the metal tube you have non-adjustable bushes....

The metal tube in my bushes went in with either hand force or a light tap....but definately didnt require belting with a hammer (sorry I mean didn't need a press)

[Sydneykid]

Just had a look at the kit again - the steel offset rods are a very tight fit in the bush (although I haven't greased them up or anything). Should they be that tight (probably where I got the idea that they would be difficult to adjust).

And I still can't figure how you would make an adjustment with the whole bush assembly wedged inside the chassis mount.

<{POST_SNAPBACK}>

No grease is not a good idea, they will squeak. My suggestion would be to remove them and grease them up. Then you can easily adjust them.

cheers

[RB30-POWER]

Fairlysure you have to use a lithium grease too on suspension bushes.

In order not to damage the rubber/poly.

[blind_elk]

No, the kit is not installed (I removed it and swapped for "standard" urethane replacements).

I've greased up the inside of the bush, greased the rod and shoved the rod into the bush - and there is no way that that rod will rotate inside the bush!

The bolt goes all the way through the rod (not like the adjustable camber bushes). So how on earth do you adjust them once installed?

[Duncan]

OK I'll try and show off my paint brush skillz

The first pic shows maximum caster, the second is minimum caster. As you can see moving the mounting point in the bush changes the length of the caster rod.

The bolt and tube have splines that lock the together, you may even need some gentle bashing since the bolt is so tight in the tube.

Once its in the bold and tube are locked together. Turning the bolt turns the tube in the tube in the bush. You use a lock nut over the normal but to keep the caster in the set location.