Jam nut importance ..

one bad dakota · Jul 13, 2016

I was having a discussion with a buddy on jam nuts. On my RK 3 link it states using loctite and failure to keep tight will void the warranty and damage threads. My old RE stuff said to use antiseize. Is this that big of a deal? If only one end of the control arm is threaded with a jam nut, I don't see how their can be much movement of the control arm length other then some minor back and forth movement at the joint end.
I certainly won't be careless about it, but it is a ZOMG moment?

akendal4 · Jul 13, 2016

If the jam nut comes loose you will get movement in the threads and wear them out. This can cause the joint to rip out of the arm.

Ronbo · Jul 13, 2016

akendal4 said:
If the jam nut comes loose you will get movement in the threads and wear them out.

X2.

VAhasnoWAVES · Jul 13, 2016

as said... youll wear out the threads, and it can fail.

I use anti seize and check regularly. I also mark my jam nuts with a paint pen so that they are easy to check at a glance.

xcm · Jul 14, 2016

Anti seize in the joint to prevent (you guessed it) seizing.
Loctite to prevent the jam nut coming loose.

Minor back and forth movement becomes massive movement.

ROBZ95Xj · Jul 14, 2016

I have all my jam nuts tacked in place

Teephphah · Jul 14, 2016

Wait until one gets loose. They can make a lot of noise for something you wouldn't think would move at all.

I had an adjustable lower control arm with a jam nut that loved to come loose from time to time (before I got a clue and finally added some lock-tite). Based on the noise it would make alone, I can't imagine it did my control arm any good when it was loose. Took me forever to track it down though, because, like you, I didn't think it was really possible for there to be an issue when both ends of the arm were, essentially, fixed.

I was wrong! Still not sure about the physics that allow that to happen, but I can definitely say that it DOES happen!

dan1977p · Jul 14, 2016

Teephphah said:
Wait until one gets loose. They can make a lot of noise for something you wouldn't think would move at all.

^ This. I don't know how anyone could drive around with one of them loose. I forgot to tighten down the jam nut on my passenger side LCA and it sounded like someone was beating the unirail with a sledge hammer every time I hit a bump.

whitexj98 · Jul 15, 2016

I had a big clunk from under my jeep from a loose jam nut on my TNT kit. I check them often now.

cal · Jul 16, 2016

I've never had the threads get so tight i couldn't unscrew them, unless something was bent (and therefor trash anyways).

I have had them come loose. I loctite everything now.

Trouble · Jul 16, 2016

The jam nut takes the load off the threads as threads weren't designed to be a rotating assembly, even though there are manufacturer arms that use threads as their flex point. Loose nut can work harden the threads quickly and lead to failure

EricsXJ · Jul 19, 2016

If your jam nuts are coming loose, you aren't getting them tight enough. Think about how big the shank and nut is? I don't know exactly what the torque capacity would be, but it would be near impossible to over-torque them.

I always use anti-seize on all control arm threads. That applies to the jam nut also. Why? Because it is adjustable and I aim to keep it that way. Years ago I had one of those RE adjustable track bars that were known to seize up, and mine did also....

On my current setup I haven't had a jam nut come loose at all and that is 14 jam nuts on the control arms alone. Get the jam nuts tight enough and you won't have any problems.

Just an opinion.

ehall · Jul 19, 2016

My UCAs have jam nuts. I tried packing them with grease to immobilize and it worked for a little while (couple of weeks) but eventually had to tighten the nuts (and again and again). I don't like using them.

kippo1 · Jul 21, 2016

This post saved me from going insane. About 2 months ago mine developed this awful racket on small bumps. It sounded like the suspension had so much slop the thing might fall apart.

I tightened my jams nuts on install and rechecked them after 500 miles or so. Read this post last night checked them this morning and 2 had loosened up. Tightened them back and checked the others. Jeep feels like a totally different ride now.

1-tonxj · Jul 21, 2016

Long time ago my xj had a Rustys front radius arm set up ,and those arms had joints with no jam nuts...now that suspension lived in another xj for years before the owner built the xj in 2008 that I bought in 2010 So those arms had around 8 Years on them running up to 38s on tons then I ran it for a year on 40 boggers before linking the jeep the arms were fine and given free to another xj owner and ran on itty bitty axles and 35s ...I know what the nut does but seems it's not the end if the world not running them .

VAhasnoWAVES · Jul 21, 2016

the threads on the rustys arms are very different. they are more like the ways on a mill than they are the threads on a rod end..

xcm · Jul 22, 2016

Not all threads are created equal, those are ACME threads.

Its not the end of the world to not run jam nuts on a conventional joint, only the end of that control arm/etc's useful lifetime.

You cant ignore details, nice try.

1-tonxj · Jul 22, 2016

VAhasnoWAVES said:
the threads on the rustys arms are very different. they are more like the ways on a mill than they are the threads on a rod end..

The jam nuts on my 2.5 jjs are always loose I think it is over flex of the joint that works them loose , but they are fine after 5 years ...going to put the New style in on my new arms they have have 30 degrees of miss alignment

lawagoneer · Jul 22, 2016

On several of our larger tractors where we have jam nuts on arms for attachments we run 2 jam nuts, one to set the arm and a second to ensure the first doesn't loosen. I would try that if I had jam nuts on my control arms. (Running RC fixed length lower control arms with my 3" lift)

VAhasnoWAVES · Jul 24, 2016

xcm said:
Not all threads are created equal, those are ACME threads.

thats the word i was looking for.

Jam nut importance ..

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Member #616

NAXJA Member

NAXJA Forum User

NAXJA Member

NAXJA Forum User

NAXJA Forum User

NAXJA Member

NAXJA Forum User

NAXJA Forum User

Similar threads