Gentlemen,
I replaced my control arms (all four)on my stock '94 XJ. I'm measuring my castor with the level app on my phone which shows 10 degrees aft on the passenger side and 10 degrees aft on the drivers side. I don't believe I have enough adjustment to have much effect with the current arms. My questions are
is this method of measurement somewhat close?
can I put adjustable control arms on a stock vehicle ?
would I need to replace upper and lower or can castor be adjusted with just the lower arms.
what is the angle I need to get to?
Thanks for any info,
Bob D

 

I have those apps on my phone too. Sort of accurate. However something is off with yours. I also have a digital angle finder that seem very accurate and a analoge one that works within about a degree. But to get your results, your axle would show a severe twist.

 

I thought that was very strange also so I checked again. Both are angled aft. I have a few shims on one side and some room to move the other back as far as the hole will let me.
do you know if the angle I'm looking for is 7 degrees?

 

7 degrees is OK. 5 degrees is factory

 

where did you measure Castor ?

across the top of the top balljoint, with the grease zerk removed is where I have been told

In theory, you should be able to adjust Castor with just LCA

You should compare the exact lengths of OEM and new LCA centres, as some aftermarket stuff is not great

My LCA are wound almost all the way in to get my angle (better), my adjustable UCA are the same length as stock UCA. I have a 3" lift

I have read that the Castor on a D30 is not the same LH and RH side from factory, dont know whether this is true, but it seems to be

You should be on a dead level surface, and use and angle finder, check pinion, driveshaft and castor angle.

The 2 x front machining of the D30 is accurate to get a pinion angle reading

 

That is correct

 

Do you know what the difference is ?

I have nearly finished my front end work (I hope), but I have to drive elsewhere to get a dead flat surface to measure everything very accurately

The main thing is my front driveshaft and pinion angle are now only 1 degree out.

I get different Castor angle readings from LH and RH ball joint top surfaces, I will use a straight edge next time, I think there may be nearly 2* difference ?

Betcha I have more work to do

 

It is supposed to be 1.5 degrees

 

I managed to get it to 7. Thanks all for your input