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jam nut question for control arms

D

dirt machine

NAXJA Forum User
Location
Davis, CA
I am going to get new adjustable control arms from Rusty's tomorrow. I know Rusty's has some junk, but the lower adjustable control arms seem like a deal for $169.

The jam nuts are another $26. Do I need these? Will I see a difference on road? Will the arms wear out sooner without the jam nut?

I am mainly concerned with having a suspension that is too flexy on road and dangerous. Let me know what you think.

Thanks!
 
You won't notice a difference on road and probably not offroad but i'd buy the jam nuts

Also, Are these Jam nuts gold plated of something? Jam nuts in the 1.5" variety go for like 5 bucks. TOPS

Nevermind, he's probably just adding 11 bucks for shipping the nuts. Figures.
 
I'm a little curious too? how would it be offroad and on without the nuts?
 
I guess i never understood the purpose of jam nuts on something that's oppositely threaded AND attached at both ends - its not gonna rotate....

now the ones on my tie rod, I understand, because its threaded the same on both ends - that way, if the rod spins, it stays the same length no matter what. The jam nuts just keep it from spinning.
 
I have jamb nuts and I keep them tight, would backing them off allow the arms to rotate providing better flex? huh I'll have to try it.
 
Without jam nuts there will be slight play on the threads which over time might start wearing out a little. My jam nut on the adjustable trackbar loosened the other day and although there wasn't a noticable amount of extra play in the steering it did make a rattling noise.

Some control arms like the JKS ones are designed to pivot on the thread rather than a flex joint and thus don't utilise a jam nut, but their design also runs on a bearing on the inside and they're also filled with grease to dampen the movement on the thread.
 
lowrange2 said:
Also, Are these Jam nuts gold plated of something? Jam nuts in the 1.5" variety go for like 5 bucks. TOPS

Nevermind, he's probably just adding 11 bucks for shipping the nuts. Figures.
Click to expand...

I picked up a used RE adjustable control arm, but it was lacking a jam nut for the heim. I was looking at RE's site last night. Their 3/4"-16 thread jam nut is only like $2, and then shipping was $15! needless to say, i'll be looking around locally to find something.

Are jam nuts uncommon enough to not be sold at hardware stores or Home Depot/Lowes?
 
I've ran Rusty's adjustable upper and adjustable lowers for going on 3 years now. I do not run jamnuts. I've had zero trouble with them. I do keep them full of grease. Everytime I'm under the Jeep, I'll put a couple of pumps in them. I don't have any clunks, looseness or anyting that shouldn't be there.

Not running jam nuts will allow the arms to twist, which in turn will allow more flex. With the nuts on, it would not allow the arm to twist. I have seen where guys run the nuts and when they wheel, they crawl under and loosen them. WHen they're done wheeling they snug them back up.

HTH

Hale
 
i have RE super flex arms and keep the jam nuts tight. i let the RR joint do the twisting and not the treads. as with rustys arms, get a joint at the axle end that twists and keep the jam nuts tight. the threads on the arms can get sloppy over time if there is no jam nut.
 
We need to clarify this before people get confused.


Rusty uses ACME thread.

ALL other arms use SCREW thread.

Please read those if you are confused about the subject. In the nitty gritty.... ALWAYS keep your jam nuts tight if you run screw thread. ALWAYS. If your running ACME, ditch it for some real control arms.
 
Last edited:
LOL...nice cut on Rustys....

IntrepidXJ - thanks for the edjumication :) makes sense now!
 
So this means that the control arms are junk? It looks like ACME threads were good on the website.

Furthermore, they are cheaper, so I would expect they would be of lesser quality. However, there is no reason to go super overkill if the ACME threads will be alright.

Lastly, can I get jam nuts for acme threads at the hardware store? They are $26 PLUS shipping.
 
89xj said:
i have RE super flex arms and keep the jam nuts tight. i let the RR joint do the twisting and not the treads. as with rustys arms, get a joint at the axle end that twists and keep the jam nuts tight. the threads on the arms can get sloppy over time if there is no jam nut.
Click to expand...

opps, i meant RE joint, not RR.

the flex arms have the RE sperical joint(forget the name, similiar to jonny joint)
 
Haleyes said:
I've ran Rusty's adjustable upper and adjustable lowers for going on 3 years now. I do not run jamnuts. I've had zero trouble with them. I do keep them full of grease. Everytime I'm under the Jeep, I'll put a couple of pumps in them. I don't have any clunks, looseness or anyting that shouldn't be there.

Not running jam nuts will allow the arms to twist, which in turn will allow more flex. With the nuts on, it would not allow the arm to twist. I have seen where guys run the nuts and when they wheel, they crawl under and loosen them. WHen they're done wheeling they snug them back up.

HTH

Hale
Click to expand...

How much lift do you have on your XJ? I too had no problems until I went up to 5" of lift. When I did I started to get a dull clunk off and on when accelerating, decelerating, turning.... Since I had less thread engagement I was starting to get some play. I ponied up for rusty's gold plated jam nuts, installed them, and it resolved the issue. Sometimes after a trail ride I'll hear the clunk again on the way home and sure enough one of the jam nuts has come loose. Tighten it back up and viola, problem solved again.
 
Interesting...

Okay, so now my $169 control arms are up to $195 control arms, plus shipping.

I can get the non-adjustable arms for I think $130. Are the adjustables really necessary. I mean, let's say I go up in lift or something, maybe an inch. I don't think that the .1 of an inch is going to make a difference.

Can anyone tell me though a cheaper place to get jam nuts? Or good $200 control arms that have a jam nut on them? Thanks.
 
xjmatt said:
How much lift do you have on your XJ? I too had no problems until I went up to 5" of lift. When I did I started to get a dull clunk off and on when accelerating, decelerating, turning.... Since I had less thread engagement I was starting to get some play. I ponied up for rusty's gold plated jam nuts, installed them, and it resolved the issue. Sometimes after a trail ride I'll hear the clunk again on the way home and sure enough one of the jam nuts has come loose. Tighten it back up and viola, problem solved again.
Click to expand...

5, 5 1/2, somewhere around there. I haven't measured since the addition of the winch and bumper. It was at 5 1/2 before with no issues.
 
Haleyes said:
5, 5 1/2, somewhere around there. I haven't measured since the addition of the winch and bumper. It was at 5 1/2 before with no issues.
Click to expand...

Dunno then. I'm sitting at the same lift and mine definitley clunk when the jam nuts are loose. Passenger side lower is always the first to loosen up and let me know.
 
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