bump stop hitting spring

[racer122]

Ok, perhaps this is the result of my going up to 6" springs on my '88, but suddenly my driver's side bump stop is getting hit by the springs as they travel (hitting the spring on the front of vehicle side).

I have a fixed aftermarket lower control arm (for 3 inch lift...), and stock upper control arms, which is probably causing the problem. Is my diagnosis correct?

Billy

 

[Goatman]

Pull the bumpstop off and grind the lip off of it. A simple cure (hoefully) for a very common problem.

 

[juicexj24]

but your fixed control arms are pulling the coil spring back at the bottom of the coil so it is bowed. You will need to get some adjustable uppers and lowers, or just uppers are the very least. I had the same problem on mine when I first went up to 6" with the fixed arms. Changed the control arms with adjustables and it solved all the problems. Juice

 

[racer122]

Thanks Juice, I thought that was causing the problem. I'll have to hunt around and see if I can find some. I was hoping to fab some up, but I can't find any writeups on projects like that.

Oh well. It's just money. Wish I had some.

 

[XJguy]

Common problem. One way to fix it is to cut the bumpstop tower from back to front but not all the way through., Leave the front part still attached to act as a hinge. then bend the tower so as the two halves you cut make contact, weld it up, paint and your good to go. The blade or wheel thickness of the cut should give you the necessary clearance so that you wont make contact. My .02

XJguy

 

[racer122]

Common problem. One way to fix it is to cut the bumpstop tower from back to front but not all the way through., Leave the front part still attached to act as a hinge. then bend the tower so as the two halves you cut make contact, weld it up, paint and your good to go. The blade or wheel thickness of the cut should give you the necessary clearance so that you wont make contact. My .02

XJguy

Ok, that's a thought for the short term. I'll still want to buy or fab up some upper control arms. Is there any way to calculate how long they need to be, based on lift?

Funny thing is that it only hits on the driver's side. But I guess it's because my track bar is too short now and it's pulling the axle a little bit to the driver's side. I'll have to do a relocate on that too. It's always something, but I guess that's what I like!

 

[xj92]

Just search under control arm lengths.

http://home.earthlink.net/~jeepcherokee/Suspension, Steering, Axles and Brakes/Control Arm Chart.htm

http://www.naxja.org/forum/search.php?searchid=29593

 

[Goatman]

Ok, that's a thought for the short term. I'll still want to buy or fab up some upper control arms. Is there any way to calculate how long they need to be, based on lift?

Funny thing is that it only hits on the driver's side. But I guess it's because my track bar is too short now and it's pulling the axle a little bit to the driver's side. I'll have to do a relocate on that too. It's always something, but I guess that's what I like!

It's going to be an issue no matter what you do with your control arms, unless you have a relatively short lift and long arms. With the added height, the axle swings futher back when it droops, causing the spring to make contact with the bumpstop. Actually, adjusting the upper control arm will do nothing, since the lower control arm is the one that positions the axle. If you want to solve it in the most elegant way, get longer lower arms and do what Rich suggested and slightly cut the bumpstop tower and re-weld it with a slight angle back. On all the XJ's I work on, I just grind the lip off of the bumpstop, which is a simple improvement. Changing to aftermarket lower control arms will allow more droop, so even with an improvement from a longer arm, you can still hit the bumpstop because of more droop.

 

[racer122]

It's going to be an issue no matter what you do with your control arms, unless you have a relatively short lift and long arms. With the added height, the axle swings futher back when it droops, causing the spring to make contact with the bumpstop. Actually, adjusting the upper control arm will do nothing, since the lower control arm is the one that positions the axle. If you want to solve it in the most elegant way, get longer lower arms and do what Rich suggested and slightly cut the bumpstop tower and re-weld it with a slight angle back. On all the XJ's I work on, I just grind the lip off of the bumpstop, which is a simple improvement. Changing to aftermarket lower control arms will allow more droop, so even with an improvement from a longer arm, you can still hit the bumpstop because of more droop.

OK then, I had assumed (and we know how much trouble that can cause) that the bumpstop was at the proper angle). I do have fixed aftermarket lower control arms (I can't remember who made them, but I bought them at 4x4 wholesale in Denver). However, they were for a 3 inch lift and I'm now at 6".

I'll grind down the lip on the bumpstop for now.

Oh, btw, I actually had searched on this topic, but apparently had not done so very effectively! Thanks for all the help.
Billy