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Discussion Starter · #1 ·
On my rod I have a Mustang II front suspension and the drivers side lower ball joint failed. See the pic. It literally broke the shaft just below the theads. My car is extremely low and when it broke (slowly backing up from checking the air in the tires) the frame went to the ground. Luckily for me it didn't brake when I was actually driving on the road. Has anyone seen this before? I installed a new ball joint from NAPA, SKU 2601042. The new part says "hardened shaft". Hopefully that will not happen again. Another issue I am now having is the nut on top of the new ball joint doesn't tighten down low enough to get a cotter pin in. What's up with that?
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I agree with 2Old, those Chrysler type ball joints usually stick thought a MII spindle too far to tighten properly. Most kits I've seen come with a spacer that goes under the nut. The spacers I've seen were around 3/16" thick (I'm working from memory).

Also, check the fit of the taper. If it is loose, then too much load will be on the nut. The taper should be close enough to "self lock". Any wiggle is too much.

Always use a torque wrench on ball joint studs. Very easy to over tighten them. Way too critical to safety to trust a calibrated wrist.
 

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Discussion Starter · #4 ·
I agree with 2Old, those Chrysler type ball joints usually stick thought a MII spindle too far to tighten properly. Most kits I've seen come with a spacer that goes under the nut. The spacers I've seen were around 3/16" thick (I'm working from memory).

Also, check the fit of the taper. If it is loose, then too much load will be on the nut. The taper should be close enough to "self lock". Any wiggle is too much.

Always use a torque wrench on ball joint studs. Very easy to over tighten them. Way too critical to safety to trust a calibrated wrist.
I understand what you are saying, BUT I have the opposite problem. I cannot tighten the nut enough for the cotter pin hole to even be visible in the top of the castle nut. Therefore I cannot put a cotterpin into the spindle. I idon't have a torque wrench. I am using a ratchet with a t0" handle. I'm not a young person and don't have the strength I used to so I would guess I should be able to tighten the nut as much as I can. Also, I don't know what the torque number is for this ball joint.
 

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Over torqued and/or junk parts. I've been loyal to MOOG parts because of experience and training. NASCAR uses regular MOOG screw in ball joints and don't have ball joint failures like that. I've seen them first hand at a suspension course I took with them.
 

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Discussion Starter · #7 ·
N View attachment 620952
Grind or file the nut to make it usable , once the taper is seated it holds the a arm in place against spring pressure , it doesn't hold up the car .
You say it doesn't hold up the car. There are only 3 stress related things connected to the hub. The steering ball joint, the upper ball joint and the lower ball joint. Tell me what holds up the front drivers corner of the car if not the lower ball joint? I thought the lower ball joint takes the weight and the upper just follows. Of course the steering connection is not weight bearing.
 

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Ok, point well taken. What about my other post regarding the ball joint doesn't hold up the car?
It absolutely does.....spring sits against lower a-arm, spindles is attached to wheel and to lower and upper ball joint. Lower joint is carrying the load.....spring force against the a-arm is working to overcome the vehicle weight on the front.....lower joint is under constant force by the lower end of the spindle trying to pull the joint up out of the a-arm while the spring is trying to push the a-arm down.
Top ball joint is just the follower joint....that is why it is of smaller construction.
 

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It absolutely does.....spring sits against lower a-arm, spindles is attached to wheel and to lower and upper ball joint. Lower joint is carrying the load.....spring force against the a-arm is working to overcome the vehicle weight on the front.....lower joint is under constant force by the lower end of the spindle trying to pull the joint up out of the a-arm while the spring is trying to push the a-arm down.
Top ball joint is just the follower joint....that is why it is of smaller construction.
Took 5 hours for someone to correct me , hey folks wake up !
 

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...Another issue I am now having is the nut on top of the new ball joint doesn't tighten down low enough to get a cotter pin in. What's up with that?
I wonder if the taper is different/wrong? That could cause the stud to not protrude thru the spindle far enough.

Russ
 

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Discussion Starter · #14 ·
Thanks to all. By the say 2old2fast.....don't talk it personally. You're still on my read list.
I wonder if the taper is different/wrong? That could cause the stud to not protrude thru the spindle far enough.

Russ
I did not check the taper measurements the new BJ compared to the old BJ. I hate to do things over but it looks like I will need to AGAIN raise the body, remove the wheel, jack the lower control arm, remove the BJ nut and let the spline out to see if I can determine what the heck is going on.
 

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While you are checking, make sure you have a 772 type ball joint (Moog number). There is a 727 ball joint that has a larger taper, but will screw into the 772 threads. I did modify a set of MII spindles to accept the 727, but it takes a 7* reamer.

The 727 is a true lower ball joint for large Chrysler cars. The 772 is an upper ball joint, but has been used by aftermarket manufacturers as a lower BJ in street rods. There has been a lot of debate over the years as to whether this is a good idea and occasionally you will read or hear about one failing, but I haven't heard of a failure in years.

The 727 has less travel than a 772 and will bind against the housing if the suspension has a lot of travel.
 

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Discussion Starter · #16 ·
Unfortunately the one I currently am working with is a NAPA SKU 2601042. It does list it fitting many Chrysler/Dodge vehicles but I could not get any further specs. What you are telling me sounds like what my problem is....that the spline will not go into the housing because it is slightly larger. Maybe I should just go ahead and order a MOOG 772....what do you think?
 

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Just thought of something else. If your suspension is Total Cost Involved (TCI) then it may have a different size lower BJ. Seems that I remember someone (may have been Fatmans) that changed their lower BJ sizes after a failure on a customers car. They may be using a proprietary size to prevent using what they consider the wrong BJ. It was TCI or Fatmans, may have been both. This was a long time ago and my memory is fuzzy.

As to brand, if I have a choice, I will use Moog every time.
 

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Discussion Starter · #18 ·
I
Just thought of something else. If your suspension is Total Cost Involved (TCI) then it may have a different size lower BJ. Seems that I remember someone (may have been Fatmans) that changed their lower BJ sizes after a failure on a customers car. They may be using a proprietary size to prevent using what they consider the wrong BJ. It was TCI or Fatmans, may have been both. This was a long time ago and my memory is fuzzy.

As to brand, if I have a choice, I will use Moog every time.
OK, I went ahead and bought from Amazon the MOOG K772. Can't believe it was so much less than MOOG on line. Even getting it direct from MOOG it was twice the price. I did send an email to MOOG asking if the Amazon K772 was the same as the one they sell direct. Probably get it Thursday/Friday. I think I'll wait till that comes before I take any further action.
 
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