Increase caster angle mod.

[UK67]

Found this mod on a US forum to improve on the non existent self centering of the Borgeson PAS. Remove the top control arm and slot the cross bar mounts 1/4 inch. This means you can move the bar rearward and so increase the caster angle to about 4 degrees. The top control arm assy can be easily removed by first compressing the coil spring and then breaking the top ball joint. You will need to find someone to mill the slots though! May be useful on standard PAS as well but not sure.
Haven't driven far but definitely an improvement and gives a more relaxed drive without continual steering adjustments

 

[Forrest Gump]

I like the idea of getting more caster with your slot mod, it just worries me that it might weaken them?

Ive added more caster by putting most of the shims at the rearward mount. It doesn’t look too pretty, but the extra caster certainly makes a big improvement to the steering.

 

[UK67]

I like the idea of getting more caster with your slot mod, it just worries me that it might weaken them?

Ive added more caster by putting most of the shims at the rearward mount. It doesn’t look too pretty, but the extra caster certainly makes a big improvement to the steering.

Just about maxed out on the rear bolt shims so it was either this mod or spending £500 + for some Global West arms. I also had the concern about weakening but it appears a common mod on both C2s and C3s in USA without any negative feedback. Some plug the unused part of the slot to prevent any chance of the rod moving.

 

[Forrest Gump]

Its hard to know how much load goes through the spindles. I expect they're well over-engineered so still fine when slotted.....I'll probably follow suit!
Are you still keeping extra shims on rear bolts as well as the adjustment via the slot?
I've seen set-up specs suggesting going up to 7 or 8 degrees of caster where adjustable arms are fitted.

 

[UK67]

Yes still kept the shims and both wheels now measure 4 degrees using a cheap caster/camber level gauge. Would like more but this would mean 1/2 inch slots - not recommended or expensive adjustable arms. Apparently over time the frame sags under the weight of the engine meaning the suspension geometry changes! You can get offset spindles which reduce the shims required but this won't help the caster.

 

[Forrest Gump]

Yes still kept the shims and both wheels now measure 4 degrees using a cheap caster/camber level gauge. Would like more but this would mean 1/2 inch slots - not recommended or expensive adjustable arms. Apparently over time the frame sags under the weight of the engine meaning the suspension geometry changes! You can get offset spindles which reduce the shims required but this won't help the caster.

Your shimming is similar to mine.
I think offset spindles would be needed for when camber is still too great with all shims removed. I’ve never heard of anyone needing them but someone must buy them. I was initially hopeful they were for increasing caster - but no!