So, for the 2nd time in a month and a half or so..the cotter pin on the PS lower ball joint has been sheared off. The first time I just happened to look over while underneath and noticed it. This time, I was getting ready to back into my parking spot at work when the whole front end just slammed down.

I got underneath it with the help of a forklift, and noticed the nut laying next to the ball joint and the pieces of pin still inside. Fortunately, the damage appears to be just a bent piece of wheel well trim and obviously a stripped out ball joint, but wont know for sure until I get it home.

I'm going to put a new Moog Ball joint in there when I get home, but what could be causing the movement enough to shear the pins? The first one I just figured was a cheap pin..but this was one that comes from Moog (not that they're guaranteed to be perfect).

Any ideas?

 

When replacing the ball joint that just failed use the new one to check for a worn taper/snug fit in the steering knuckle before installing it in the control arm.

 

That part of the ball joint is not supposed to spin, its swedged in place when you tighten the nut by the taper.

 

right. thats why Im befuddled as to why this keeps happening.

Wrong size ball joint? They are different compared to the Moog replacements, as well as the ones that came off the car/control arm.

 

Did you replace the ball joints once already? If so, were they Moog replacements or Chinesium? If the wrong ball joint is used damage will occur.

 

The taper has to be the same as OE, otherwise I think they are the incorrect joints. Are there part #'s on the new joint to compare to the part # on the box?

 

If they are different, they are probably the wrong part, you are very lucky this did not happen while driving.

 

The ball joints that are in the car came pre-installed in the control arms I bought from RPS. RPS had these listed as correct control arms for a 442, however upon receipt I noticed the bushings were different than the ones that came off, and the center shaft for the upper arm (can't remember the name) had bolts/washers instead of the shaft being threaded on either end.

When I noticed the first time that the pin had sheared off, I tried to put the nut on from the new Moog ball joints I have, but it was a different size. The Moog piece matched the arms that came off the car, but did not match what was in the car. What is on the car now is a bit bigger, so I wonder if the entire thing is simply too big and not seating as it should.

I'm hoping to be able to get the car trailered home tonight, and if I can I'll probably go ahead and check the DS as well as the uppers to ensure they're the same size.

 

Is this the Moog Lower Front Ball Joint you are attempting to use?

https://www.moog-suspension-parts.com/moog-k5103

 

oh, absolutely.

 

There are multiple threads of the horror stories with import tubular arm ball joints. The Moog joints should fit with no mods.

 

I believe so, but I'll have to check the PN when I get home.

 

These aren't tubular though. They were advertised as OE replacement.

 

Probably worth a call/email to the supplier RPS.

 

I called them when I received them about how they weren't correct. After arguing with me that all GM A-body are the same and hearing me point out the subtle differences, the guy finally went "oh, well I didn't know that".

 

I can't begin describe the numbers of times I've listened to a Parts (Counter) person blabbing about how he's 100% positive it is correct only to be rebuked by facts.

 

I tried looking up RPS's website again to see if it gave a part number for the ball joint used, and it looks like they're either no longer in business, or at least no longer running a website/social media. I know when we did talk (before they arrived) he said they were being drop shipped from the manufacturer out of PA. I'll have to look back at my notes at home/invoices/whatever to see if I have it written down who the manufacturer of the control arms is.

 

The nut on the ball joint may not have been tight enough. They need to be cranked down to set the taper. Otherwise it's possible to have the joint spin in the spindle. I've seen that happen more than once.

 

The cotter pin is just supposed to lock the castle nut in place so it can't turn and unscrew itself. So you're saying the nut was stripped off the shaft?

 

It is nearly effortless to shear the cotter pin off. In fact I don't think any flat rate tech has removed a cotter pin more than once on a junk part.

 

If it’s that easy for a vibrating nut to shear the cotter pin, why are they even used? I can understand leaning on a breaker bar on the nut would shear the pin, but just the nut and normal driving? If that happened, all of our vehicles would fall apart, especially when driving on crappy roads.


So I say there’s something else going on.

 

correct. We tried to move it into a better position for the trailer and literally as soon as I shifted to drive (still fully engaging the brake) it slammed down again. This time, it left a mark..so I'm a bit more upset.

I've packed tools in the truck, and after work I'm gonna get the ball joint swapped out and limp it home.

 

I really think it's the wrong size ball joint. I don't understand however after many miles (many bumps) this is now a problem. When I pulled the lowers to re-index the springs last summer, I thought it was odd that I didn't have to use the fork to separate the ball joint from the spindle. Well, if it's not able to fully seat due to the shank being too large..that may be the culprit.

 

A couple of recommendations for you. You will need a Dial Caliper in order to accomplish this.
1. Using a Dial Caliper measure the opening at the bottom of the Spindle. Write this down for later.
2. Using a Dial Caliper measure the opening at the top of the Spindle where the Lower Balljoint Nut is tighten down. Write this down for later.
3. Using a Dial Caliper measure the thickness of your Spindle where the Lower Balljoint passes through. Write this down for later.

At this point you are 49% done, lol if you are still with me. Grab the Balljoint that is causing you the problem.

4. Using a Dial Caliper measure the width of the Balljoint taper at the largest point of the taper. Write this down for later.
5. Using a Dial Caliper measure the width of the Balljoint taper at the smallest point of the taper. Write this down for later.
6. Using a Dial Caliper measure the length of the Balljoint taper. Write this down.

At this point you are 97% done.
Compare each of your measurements to find any discrepancies.

Having said all of this I will now tell you of my experience just last year on my Sweetheart car. It involved the Lower Balljoint as well. Everything was installed and torque down to spec. The Balljoint nut ended up so far down on the Balljoint stud that the cotterpin was totally useless. For me it turn out that the Balljoint nut was more of a half castle nut. For me it was a simple fix requiring a trip to the Stealership to get the correct length castle nuts.

 

I'm definitely curious as to the taper difference. The nut on the bad one is a 15/16, whereas the nut on the Moog part as well as the original are 7/8. It does protrude a good bit, but if it's too big to properly seat.. thats a problem.

 

Sorry I thought you bought tubular control arms. Regardless, it should be easy to get this rectified.

 

Post #8:

 

Hopefully the fender wasn't damaged.

 

it was a little bit just behind the tire. Not a ton, but enough.

 

The '69-72 A-body suspension has a 7-degree taper to the ball joint stud. If the aftermarket control arms came with the wrong balljoints installed, the taper on the stud was probably incorrect as well and didn't seat the ball joint stud fully into the spindle. When working on 50 year old cars, you really can't trust part suppliers to know the correct specs. Never assume a replacement part is correct, and always compare the old part to the new looking for inconsistencies. You are very fortunate this happened in your driveway at low speed and not on the freeway at 60mph.

 

Just make sure you know where the Moog part came from. They aren't always made in U.S.A. They have many different places they can come from. It should be on the box. If no box, there's no way to tell. Many Chinesium parts are flooding in from "Chinesia". Quality has become quite questionable.

Where are Moog parts made? The answer may surprise you! | Suspension.com

 

I have never had an issue with a Moog part no matter where it came from.

 

I'd have to look.but if it gets the car home, that's my priority at this point.

 

Is the part the same for all A-bodies, or is it differedifficult Olds/Chevy/etc?

 

That's good. But there are some that have. They're not a slam dunk like they used to be.

 

I copy this from my other post as I thought that I was replying here lol.

[size=16px]Another thought on this..... Back in the 80's there was a Company that everyone knew for pistons called TRW. I have always used Moog parts when it came to suspension parts. My supplier was out of Moog Balljoints as there was a problem that I no longer recall. Anyway he sent some TRW Balljoints and the nut that came with the joint was oversize. So that is another area to check especially being that you mentioned the castle nut was size differently.[/size]

 

I'm still amazed that the threads on the shaft shaved off. That should not happen to a quality fastener.

I would be very concerned about the ball joint on the other side.

 

Unless I'm missing something the OP has NOT identified the ball joint(s) manufacturer.

 

Yes, the upper and lower balljoints are the same for all '69-'72 makes: Cutlass, Chevelle, Malibu, Lemans, GTO, Skylark, GS, etc.

Rodney

 

Yeah, I think you missed something. In the first post he said he was going to install a Moog ball joint in when he got it home. I was just saying that nowadays, Moog doesn't necessarily automatically mean quality parts anymore. Doesn't mean they're all junk, either. Got to make sure your comfortable with country of origin. Of course, there's a lot of garbage out there now on stuff that used to be good.