Caster totally whacked after drop brackets

Man, I never though I'd say it but I'm really getting sick of posting new threads here. In the past month or so I've done a heavy amount of modding and now I feel like it's all catching up with me. Totally feel like "that guy".... Tried searching too but everyone was just kinda openly speculating.

Anyways, I installed my RCX drop brackets a few weeks ago. It rides like a champ, but the steering is trashed. I can tell the caster is WAY off. Wanders all over the road, no return-to-center at all, and generally feels very sloppy. Then I started thinking about it, and it doesn't make sense. I have fixed RE lowers that measure exactly 15 15/16" bolt center to bolt center. JUST shy of 16". After looking at some of the charts online spec'ing lengths with drop brackets, there's no way their measurements are correct. If they were I would have TONS of positive caster. I also have Rokmen HD uppers with frame-side JJ.

Did an alignment tonight for the first time since the brackets, and was amazed at what I found. Lowers are just shy of 16", uppers are a half turn from all the way it (the eye's wouldn't line up all the way in), so they're at 15 1/16". My caster is now at 1.3 degrees!!!!

Do the drop brackets scoot the upper arms an inch forward or something? My axle is already as far forward as I want it to go, so adjustable lowers are not gonna happen, nor are caster shims. Is my only option ordering shorter uppers, or cutting my Rokmen's shorter? This geometry is really confusing me.

Here were my before and after specs. Very pleased with the camber. Means my axle isn't bent like the last one lol. Also pleased with how close I was able to get the toe, and the fact that my steering wheel is finally somewhat straight. But that caster... that's gotta go. Quick. My thrust angle isn't looking too good either.

well if im not mistaken, you need more positive caster (7.5 degrees i think is spec). in which case all you need to do is lengthen your lower arms to get that.

you should try reading the WHOLE post before replying

Yes the brackets push the arms forward.

You need shorter uppers.

I dealt with this earlier this year.

Cali your reading comprehension skills are much appreciated lol.

Cutting up $300 arms? That's what I'm all about. How much do you think I should start with?

I dunno who came up with the measurement chart, but that ish is obviously cray.

Rather than cutting up a set of fixed arms, you could always sell them and put on a set of adjustables.

The lowers are fixed, it's the uppers I would be cutting. I was thinking about taking a half inch or so off them, allowing the joint to screw in farther.

Can you post of pic of how the UCA and LCA are mounted on the frame side with the DB's? The drop brackets SHOULD move both upper and lower CA's in a fixed relation to each other - not push one forward without pushing the other the same amount as well.

I have the same problem after I installed my RC Brackets, however I have adjustable lowers and stock uppers. I can tell you that the brackets drop down the arms an equal length (I believe 4") and maybe move them forward 1" at most if I am not mistaken. Point is that they do move both upper and lower arms at the same time.

Now, I noticed mine wanders al over the road too and after adjusting the LCA and aligning, it improved a bit since my caster is the same as yours.

But know that I see that I need 7.5 degrees, I need to lengthen my LCA so it drives straight.

You can either cut your upper arms or get adjustable uppers. As long as you can get the proper angle, do what it takes and is best for your wallet. How much lift do you have?

DanMan2k06 said:

I dunno who came up with the measurement chart, but that ish is obviously cray.

Click to expand...

:roflmao:

My 2001 is at 4", running dropped brackets, adjustable UCA and LCAs and a LP D30.
When the front driveshaft's forward u-joint is set to have 1 degree, or less, of misalignment, per the FSM, it ended up with 3 degrees of caster.

I installed a set of adjustable ball joints and gained 2 degrees of caster, which brought it to an acceptable 5 degrees of caster.
The only way for my XJ to gain more caster is to increase the u-joint misalignment, which causes vibes, or to cut, rotate and re-weld the Cs.

I have fixed RE lowers that measure exactly 15 15/16" bolt center to bolt center. I also have Rokmen [adjustable] HD uppers with frame-side JJ. My axle is already as far forward as I want it to go, so adjustable lowers are not gonna happen, nor are caster shims

Click to expand...

in which case all you need to do is lengthen your lower arms to get that.

Click to expand...

Rather than cutting up a set of fixed arms, you could always sell them and put on a set of adjustables.

Click to expand...

You can either cut your upper arms or get adjustable uppers.

Click to expand...

This thread is full of win...

I'm at exactly 5" lift in the front using the 'dirty' method.

AeroSync said:

I have the same problem after I installed my RC Brackets, however I have adjustable lowers and stock uppers. I can tell you that the brackets drop down the arms an equal length (I believe 4") and maybe move them forward 1" at most if I am not mistaken. Point is that they do move both upper and lower arms at the same time.

Now, I noticed mine wanders al over the road too and after adjusting the LCA and aligning, it improved a bit since my caster is the same as yours.

But know that I see that I need 7.5 degrees, I need to lengthen my LCA so it drives straight.

You can either cut your upper arms or get adjustable uppers. As long as you can get the proper angle, do what it takes and is best for your wallet. How much lift do you have?



:roflmao:

Click to expand...

he has adjustable uppers, but they are bottomed. he has fixed lowers and has stated he doesnt want to push the axle any further foward with the lowers

woops, my bad. missed the fixed lowers part. i dont really see how putting the adjustable lowers on and adjusting for proper caster is going to push it forward that far. but you arent going to do it so, i guess you are screwed! time for a 3 link!

i dont think the brackets push the arms forward, as much as they put them horizontal... which is what your trying to do. if the arms were angled before, the radius they are moving in will inevitably change your specs.

if the castor adjustor on the drop brackets is maxed out... your only option is adjustable arms.

How much adjustment is needed here to get it back into spec? If we're talking like some 1/4" shims on the back of the LCA's then I'm not worried about it. I just don't want my axle moving forward another inch blah blah. I've already had to gratuitously trim my from bumper end caps because of the drop brackets.

Yea my bad I misread the adjustable UCA part.

Maybe try spacing the shims like you say by half an inch and see how it drives? That should make a difference.

DanMan2k06 said:

How much adjustment is needed here to get it back into spec? If we're talking like some 1/4" shims on the back of the LCA's then I'm not worried about it. I just don't want my axle moving forward another inch blah blah. I've already had to gratuitously trim my from bumper end caps because of the drop brackets.

Click to expand...

If you maintained the alignment blocks in the LCA pockets, then it is pretty easy to loosen the LCA bolt at the drop bracket, slide the LCA forward with a crow bar and slip some shims in there to see if you can affect it enough to get it into spec. I think I have around 3/8" of shim on my fixed LCA's on my MJ (at around 6.5" of lift). Its never been aligned and it might be overkill, but it solved my floating wheel problem. I would start with 1/4" and check it on your alignment rack again.

Have you thought about getting adjustable lower control arms?












































:shiver: or maybe some adjustable balljoints

I messed around with it some more tonight. Before, my lca's were slid to the very back of the adjustment bracket. I pushed them all the way forward (maybe an inch?) and got it to 4.8 degrees on both sides. I'd like a little more but is a LONG way from where it was. The difference in handling is amazing. I'm going to call rokmen tomorrow and find out how deep their threads go. If there's room, I'll shorter them. Otherwise I'll start looking into adjustable balljoints.