240sx ball joints

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DavidM

New member
Me again. I'm going through my list to prep the car for the Road Atlanta race later this month. I put on the list to replace the control arm ball joints since I have no idea how old they are and the boots for the front ones are ripped up pretty badly. I got some Moog replacements and the loan-a-tool ball joint press from Autozone.

I was looking at the joints last night figuring out in my head how this was going to work. Turns out the left front ball joint has been welded into the control arm?!? Not just a little tack weld either. I'm wondering why? Does this indicate that the ball joint was sliding in the control arm? Is this common practice? The right front one was not welded and neither were the rears.

Are ball joints something I should worry about as wear items? I was concerned because the boots are ripped. I could probably just replace the boot if I don't need to worry about the joint itself.

The tool I got from Autozone doesn't seem to have a good sized cylinder for the front control arm either. The one that is big enough for the joint barely fits on the arm and is not flush. I'll see how it works.

I did manage to figure out a wiring issues yesterday. At least I fixed one thing....

David
 
I don't think they're a huge concern on these cars, but I did replace both front joints a year or two ago just because, as you noted, I had no idea how old they were. I remember having to press both of them out (isn't there also a snap ring holding each one in?), so it is kind of puzzling that one was welded in. Sounds like you might have to pick up another control arm? Oh, and I think I just used a couple of sockets and a BFH to tap them out/in. That was before I had the press....

I also got one to try on the rear - as I'm sure you know there is no aftermarket listing (or OEM if I recall correctly) for rear ball joints on our cars, but I did find a few places where people have stated the ones from a B13 will work on the rear the 240. I bought one (confidence is not that high), and if it works I'll replace the other.
 
I got the Sentra ones for the rear as well. The rears don't look as bad as the fronts, but I figured I'd replace them while I was doing the fronts. I found a posting where someone measured the Sentra ones compared to the originals and there was something like .1mm difference so they should fit fine.

The front joints have been replaced at least once as they have the grease fittings on them. There is a circlip that goes around the top, but I guess if the hole is loose the the joint could move some. I have spare control arms, but of course they aren't setup for the spherical bearing. I'd have to get that done. Likely isn't going to happen in the next couple weeks. I could try to grind down the welds to press this one out and then have it re-welded after the new is in, but I'm not sure I could grind the welds without damaging the control arm.

Always something.

David
 
Grind them out or get a new knuckle. The last thing you want is a ball joint issue at the track and not be able to fix it.

You don't need to press them. Take a hammer and hit the knuckle perpendicular to the ball joint. It should pop out.
 
I had one ball joint come loose on the wife's Altima a few years ago and had to weld it in place. still on the 130k mile old OEM ones on my S14 though. They hold up pretty good all things considered.

If it were me, I'd go ahead and try to grind the old one out and replace it. if that fails, you have a spare arm and can press the spherical into it if you have to.
 
a tack weld is common... if they welded the whole thing, they may have bougered the LCA changing the ball joint.

and Tristan, the press they are referring to is for swapping the ball joint in and out of the control arm, not for popping it loose from the knuckle...
 
Tristan Smith said:
I use a press for that. I think a hand tool would be a pain for that. But I guess it would work.
Click to expand...

I just whack the knuckle near the joint with a ball peen hammer until it comes loose. about 4-6 good whacks and I'm back to work. it helps vent some frustration, and you don't have to worry about mashing the threads on the end of the ball joint or trashing the dust boot with a pickle fork.
 
I worked on the car some last night. Took me two hours to do the left rear ball joint. :( Took me 30 mins to get the control arm off. I got a tool to press the stud out of the hub, but there's not a whole lot of room to work with when the axle and everything else is still attached. I wound up unbolting the control arm from the rear sub-frame and then the tool could fit to press out the ball joint stud. The stud did not want to come out and I had to whack the control arm a couple times while the tool was pressing on the stud to get it to pop out.

I then had to figure out how to use the damn ball joint press. The instructions that come with it are lacking. 20 mins later and I had the parts in the right order to press out the ball joint. It actually pressed out pretty easily. It was definitely due for a change as I could move the stud around just by grabbing it with two fingers. Reversed things and pressed the new one in. The Sentra ball joint works just fine. Felt a little tighter pressing in, but I figure that's not a bad thing. I think spent 10 mins dorking with the ball joint boot cause the instructions say you should press it on till it touches the circlip, but the there was no way in hell that it was going to go on that far.

Then I had to put the control arm back on. Sounds simple.....unless you have a spherical bearing setup like mine on the mounting points to the subframe. The mounting points each are about 2in long. What Bob did was put a spherical bearing in the center of each mounting "tube" on the control arm. This leaves about a 1/2 gap on either side of the bearing that needs to be filled in to mimic the original metal sleeve that keeps the bolt from squishing things. So there is a metal spacer that fits on either side of the bearing. These of course are not connected to anything and just fall out. They are round and tend to roll everywhere. Needless to say I spent much time trying to hold the spacers in while I bolted up the control arm and then hunting around for them when they fell out and rolled away. Probably took me 45 mins to get the damn control arm attached and it's still not torqued down.

I figure I can do the other side in maybe an hour. We'll see.

I'm going to try and take some pics of the spherical bearing setup on the control arm when I do the other side. It just seems like there's got to be a better of doing it.

The adventure continues tonight.

David
 
David..
My S14 has sphericals in the other arms, but not in the control arm. I just use either washers or short sections of 3/4" tube w/ 1/2"ID as spacers.
it'll probably take about 5 hands, but what I do is stick the bolt through the subframe with just enough sticking out to hold one spacer bushing. hold that with one hand.
then I grab the arm with the other hand and hold the second spacer on the other side. balance the control arm on top of that arm and carefully work the bolt through the spherical bushing.

get all that slid together on one bushing, then stick a nut on there so it won't fall apart and repeat on the other side.

when all that's together and the control arm pivots on the subframe, then reattach the ball joint and sway bar.

yeah, it's a pain.

____________
Any idea what size sphericals are used in the control arm? I found some for a FD or FD RX7 through MazdaComp/Mazdaspeed that are sphericals with rubber covers on them. They look just like the stock rubber pieces for our cars, but they only have a 10mm ID bore in them. The good news is they press right into the factory arms. the bad news is you have to convert all the hardware on the car from 12mm to 10mm.

there's also a guy selling spherical conversion kits for the rear knuckles. if you're interested, let me know and I'll put you in touch with him. not sure if he's got any more sets right now since he builds them in batches and does group deals on some of the 240SX forums.
 
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Took off the left front control arm last night. That is the one with the ball joint welded into it. Here's what I saw:


balljoint2_web.jpg

balljoint3_web.jpg


I decided to punt on trying to grind the welds down. I figured I wouldn't be able to do it without hosing up the control arm and then I'd really be screwed. The ball joint was still pretty solid and I don't think it'll be an issue. I taped up the boot some and put everything back together. I'll start trying to find the pieces to put the spherical bearing in a spare control arm.

The spherical bearing setup in the current control arm is pretty cool. Looks like a sleeve was put in that holds the bearing and then welded to the control arm. The sleeve is machined on the inside with a groove and a circlip holds the bearing in place so that you can actually replace it easily. There are tubes glued? to either side of the bearing that the bolt slides through so that you don't need extra spacers. I gotta believe Bob bought this from somewhere. Anybody have any idea who makes them? Here's some pics:

controlarm1_web.jpg


controlarm3_web.jpg
 
David - unless it's on the other side, it doesn't look like the sleeve is welded to the arm? If not, couldn't you just press out the entire assembly and press it into another arm? Also, it looks like the inner sleeves actually press into the bearing, kinda like these misalignment bushings (which I was planning to use whenever I get around to working on a spherical setup).

I swear I remembered reading that Bob made his own bushings, but I can't find that thread now. I do remember someone mentioning a place in Topeka called West Tek; there used to be (may still be) a guy there named Tim who had made up a few sets of the bushings. Also, a company called SPL Suspension used to list individual spherical bushing assemblies for our cars, but now all I see is a listing for the ones that going into the rear knuckle. May be worth a call to them to see if they still have anything in stock.
 
The sleeves are most likely just press-fit into there.

That's pretty common stuff from a guy that knows what he's doing actually.
Those bearings are probably a COM10 or common size from Aurora or FK or someone, which have a standard outer and inner ID. then you take a piece of DOM tube and machine it to the right ID and OD in a lathe.. the OD matches the factory bushing and the ID is like 0.001" smaller than the OD of the monoball. that provides a decent press-fit, then you hold it together with the circlip just to be sure.

same for the metal sleeves- they're just a shoulder bushing with, say 0.630" OD so it presses into the bearing, then a 12mm or 1/2" ID.
cut them to length so they just fit indie the front subframe and voila.

it's probably 30 min of machine work for someone that knows what they're doing.
 
FYI, SPL is working on a custom front control arm solution. They sold a NAMS (japanese/chinese import brand) arm under their name for a while, but have removed them from their webstie. not sure if they can still get them or not.

As for how the arm is constructed, IIRC the lip curves inward so there's a reasonable amount of meat contacting the center bushing. it's probably welded to the bushing on the inside of that lip, which isn't visible in the photo.
 
Left this pic out of the other post cause there's a 4 pic limit. You can see where it's welded pretty much all the way around. Might be able to cut out the sleeve and clean it up, but would rather duplicate it. I'll have to compare it to a stock arm to see what was actually done.

controlarm2_web.jpg
 
Did the right rear ball joint over the weekend. It was shot and needed to be replaced so I'm glad I did it. Took me a lot less time since I knew what to expect.

The right rear control arm spherical bearings were done differently than the left rear. They were done similar to the front control arm with an inner sleeve pressed into the bearing for the bolt to slide through. Of course, it looks like the sleeve was machined a touch too big so they had to replace the stock bolts with some that were a touch wider so there was no slack between the bolt and the sleeve. And the sleeve wasn't cut at a right angle so the end is crooked. Still a better job than the other side. I'll have to go through and redo the sphericals for the rear control arms at some point.

David
 
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