Front control arm contacting shock mount

[Gordon Land]

Hey folks,

Got a quick question. About six weeks ago I installed new rokmen front control arms. I've noticed that the lower control arms are making contact with the back lip of the shock absorber mount. I'm thinking that I might grind that lip on the shock absorber mount to create more clearance between the arm and the lower part of the shock mount to eliminate the contact. The jeep has a 4.5" lift with short arms.

Before I go and do something stupid, is there any reason that it would be a bad idea to remove the material at the contact point? The way I see it, repeated contact may eventually lead to something cracking. Flip side to that is that it was built that way for a reason. Thoughts?

 

[Jerry Bransford]

Can you post a good sharp well-lit photo of the problem Gordon?

 

[Chris]

Yes, I agree, a picture would be very helpful.

 

[Gordon Land]

Took this one this afternoon. Apologies for the lighting. Look for the shiny spot over the arm, you should see the deformity

 

[Jerry Bransford]

That photo is so dark I can't see anything, please use a flash. What little I can see doesn't seem like the control arm is anywhere near the shock but the photo is so underexposed I can't tell for sure.

 

[Serbonze]

Are you taking about this spot?

 

[Jerry Bransford]

Oh gotcha, thanks. What is your current caster angle? A high caster angle would make it more likely for that bracket to rub the shock. 5-6 degrees is optimal for a 4" suspension lift, 7 degrees is the factory caster angle.

 

[Gordon Land]

Are you taking about this spot?

View attachment 4981

Yes... That is the spot. Believe it or not it was taken with a flash. The iPhone just didn't do a good job of illuminating it. Thanks for lighting it up!!

 

[Gordon Land]

Oh gotcha, thanks. What is your current caster angle? Did you tweak it up pretty high, maybe with the use of manual hubs so the resulting steep pinion angle didn't cause vibes? If the caster angle is where it should be and can't be reduced which would add more clearance between the shock and control arm, I think I'd add a little clearance at the bracket where it's rubbing the shock with an angle grinder.

Thanks Jerry!!! My apologies for the crappy picture. It was taken with a flash, iPhone just couldn't cut it. Thanks to serbonze for lighting it up!! I'm not sure what the caster angle is, bought the jeep lifted and haven't changed any geometry. Basically when I changed the arms, I measured everything before I took it out, and restored it to the same configuration with new arms. Based upon your reply, it sounds like you agree that removing material from this location shouldn't do any harm. Not putting you on the spot, I take full responsibility for my own actions and mistakes, just being clear. Thanks again!!

 

[Jerry Bransford]

I'd certainly have the caster angle measured to make sure it's not way off from the suspension lift. Your control arm lengths are likely adjustable which means the caster angle could be tweaked if it's high enough to be the cause of that rubbing. I also edited the information I wrote in post #7 above.

 

[Gordon Land]

The CA's are definitely adjustable. That's why I replaced the ones that I bought it with. I'll have the alignment done and the caster checked. Thanks again!!

 

[Serbonze]

Out of curiosity, what kind of control arms were in there?

 

[Gordon Land]

Rokmen adjustable

 

[Serbonze]

You said you replaced the control arms with Rokmen. So my question again, what control arms were in there?

If they were OE arms, I'm trying to figure out how you have 4.5" of lift on there without other issues.

 

[Gordon Land]

Sorry misunderstood you. Uppers were stock, not sure what the lowers were. They were part of the lift that was on it when I bought it, the bushings were going so I decided to replace them.

 

[Serbonze]

I saw one of your earlier posts about vibrations, but I don't think you mentioned that you are on a 4.5" lift with only front lower adjustable control arms.

Does the Jeep have a transfer case drop or a Slip Yoke Eliminator and a double cardan rear drive shaft? Are the rear upper and lower arms adjustable?

 

[Gordon Land]

The jeep is on a 4.5" lift. At the time of the previous post I had not changed the control arms yet. But it did have an SYE and double cardan rear drive shaft. When I posted about the vibrations I had just rebuilt the front DS. Still working on that. Not my dd so I dont drive it that much.

The configuration NOW is 4.5" lift, adjustable upper and lower fronts. Just changed the front springs (didn't change the height just changed the springs to metal cloak dual rates). Haven't driven it since I put them in last week. Will be installing adjustable rear CA's and new springs soon (they're on my garage floor).

 

[Serbonze]

So does the rear currently have the OE arms or are they adjustable from whatever kit was in there when you bought it?

It sounds like you have a good plan set up to move forward, I'm just trying to wrap my head around how it's currently set up.

Did you buy Rokmen rear lowers too? They certainly may have changed, but from what I remember they don't adjust shorter than OE so getting your pinion angle correct could be a problem.

 

[Gordon Land]

Current situation (rear only). It is as I bought it. (Aftermarket lowers, stock uppers, aftermarket springs).

I bought rokmen adjustable uppers and lowers and metal cloak dual rate springs. I have replaced front springs and arms. Will be replacing rear springs and arms shortly. All four corners will be consistent.

 

[mrblaine]

Hey folks,

Got a quick question. About six weeks ago I installed new rokmen front control arms. I've noticed that the lower control arms are making contact with the back lip of the shock absorber mount. I'm thinking that I might grind that lip on the shock absorber mount to create more clearance between the arm and the lower part of the shock mount to eliminate the contact. The jeep has a 4.5" lift with short arms.

Before I go and do something stupid, is there any reason that it would be a bad idea to remove the material at the contact point? The way I see it, repeated contact may eventually lead to something cracking. Flip side to that is that it was built that way for a reason. Thoughts?

It is common for larger diameter arms to contact that lip on the shock mount. It is not common to have the contact anywhere near ride height but only when drooping the axle to pull the front springs. If you have contact or almost contact at ride height, the caster angle is too high (axle leaned back at the top), lift height is too tall for arm length, arms are too large, or some combination of the above.

I clearance that spot frequently when the rig has good travel in the shocks so there is no or minimal contact at full droop or so I can easily remove springs without dropping one end of a control arm.