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BreckBJ44
11-25-2009, 06:25 PM
I need to find or buy a set of castor correction shims for a 1981 40 series. I have 2.5 degree and need 7.5 degree if such a thing is possible.

Anyone know who can make some of these?

Thanks!

J Kimmel
11-25-2009, 08:20 PM
search around, there are a couple places that make them iirc, the best wAY really is buy some new perches and rotate/weld new ones on at said angle.

DaveInDenver
11-25-2009, 08:34 PM
search around, there are a couple places that make them iirc, the best wAY really is buy some new perches and rotate/weld new ones on at said angle.
For a couple of degrees shims seem OK, but you're probably right on about 7.5 degrees.

MDH33
11-25-2009, 08:41 PM
7.5˚ does seem really extreme. How did you determine your angles? maybe your measuring method was off?

4 Crawler (http://www.4crawler.com/4x4/ForSale/Shims.shtml) makes custom steel shims. :thumb:

BreckBJ44
11-25-2009, 09:21 PM
I had the caster measured by computer at a shop. The rig was showing -3 degrees. I currently run a 2.5 deg shim during the test. Stock (or better) is from +1 to +2.

The springs are from alcan and I am ready to have him remake the F$%&ing fronts... He already had to do the rears again once...

MDH33
11-26-2009, 08:57 AM
I had the caster measured by computer at a shop. The rig was showing -3 degrees. I currently run a 2.5 deg shim during the test. Stock (or better) is from +1 to +2.

The springs are from alcan and I am ready to have him remake the F$%&ing fronts... He already had to do the rears again once...

When you say stock is +1 or +2, are you referring to the pinion pointing 1 or 2 degrees down from horizontal?

Hulk
11-26-2009, 11:24 AM
The 2.5 and 4 shims are really easy to come by. You could buy a set of both and stack them, just to see if it makes your steering work as you think it will.

I bought my set of 4 shims for my 40 at Off Road Ltd (http://www.offroadltd.com/homeorig.htm) over on Colfax.

15899

Red_Chili
11-26-2009, 12:57 PM
Eek, careful with shims in the front! Especially stacked. Unless you are using them temporarily as a check, which it sounds like you are doing.

+1 4Crawler shims. If they aren't right he will take them back and send you a different set. I would recommend welding them to the axle perch in the front.

Remember, the math is not 'simple' if rotating for pinion angle, because of the rotation of the pinion in an arc around the axle centerline (if you want to move the pinion 5* up... a 5 degree shim will overshoot). But it sounds like you are measuring simple caster and could care less about pinion angle.

BreckBJ44
11-26-2009, 07:22 PM
For the +1 - +2 caster angle, that means that the steering arms are pointing up at 1-2 degrees. A negative angle causes wandering and wear on the center arm. With a -3 that I am running, she wanders a lot and reacts oddly at bumps. I drive too much road to deal with that. Maybe going to a 4 degree shum will help a bit more, but I would prefer taking the springs off only once. ;-)

As far as pinion angle goes, it should put the pinion at the same angle as far as I can tell so the pinion and output on the tranfer are the same right? Any correction or input on this would be awesome!

rover67
11-27-2009, 08:59 AM
Dig around of 4 crawlers site, he has a lot of good info there about pinion angles.

I'd post it but it's just easier to look over there... he goes into really good detail about it.

BreckBJ44
11-27-2009, 01:30 PM
Looks good! Especially since I Really don't want to have to swap center pins. I have taken the rears off and on twice, did two primary installations (and then had to swap shackles), and am just done with messing with it too much. I think a 7 or 8 degree shim would be perfect.

Stock caster is +1 but I have heard that going to +2 makes it even more stable. Anyone try this?

60wag
11-27-2009, 05:19 PM
This is a stupid question but I have to ask, which way are your current shims installed - fat end to the front? You are spring under right?

BreckBJ44
11-28-2009, 03:28 AM
Fat end front and Spring under. Alcan just builds the spring so that the pin is the same diatance from the pin eye as stock instead of moving the center of the pack to the bottom of the arch. ugh.

P.S. Already contacted the shim guys Marco. Thanks! They seem to know thier S#%t.

K