[nUcLeArEnVoY]

Looking for a driver side steering knuckle, preferably cast 371675 (translates to part #14012595) since that's what i currently have on my '79. The parts manual will show this is for 80-81 f-bodies and b-bodies with 11" rotor, but also works on the 79; and was also used in a lot of cars such as the Caprice, LeSabre, etc. throughout the 80's. The only reproductions I can find are drop spindles, which I don't want.

Experienced a catastrophic lower ball joint failure on my passenger side while turning in a gas station. Entire stud just popped out of the spindle and the castle nut was lying in the control arm that was laying on the ground, and the cotter pin was sheared clean off and the stud threads wiped. Looked at the mounting hole on the knuckle and it's egged out/out-of-round, possibly having contributed to the failure.

Anyway, I was able to find a NOS passenger side spindle on ebay and immediately bought it. Even though it will replace the side that actually failed, I want to source a driver side one, too just in case since I ordered all new ball joints all the way around. (I'm still running the original upper ball joints that are riveted on.)

I will gladly shell out a premium for a NOS part since now I'm paranoid about getting a used one, but if all you got are used units, it NEEDS to be in good, serviceable condition, and all of the tapered holes for the ball joints and tie rods need to be nice and round and usable for a proper interference fit. I don't want to mess with taking half measures on suspension work. I could have been killed the other day if I was on the highway. I love this car, but not to death.

I attached a pic of the NOS passenger one I got so you can see what it looks like. The casting number on the back side of it should read 371675.

[Scott Thelander]

WOW
you are very lucky .... it happened where it did ,,,,
mid 90's I had a 80 chev dually 2wd 10' Lance camper and a 14' aluminum boat n trailer behind
430 am monday morning on my way back from 6 days camping eastern washington fishin alta lake and columbia river and on my way to work
getting ready to take my exit home .. turn the blinker on and my truck makes a thump sound and then grinding ,,, looses steering basically and sends me
right 2 lanes and into the grass median with a gentle right turn thankfully ,,,, the passenger upper ball joint had pulled out of the socket,,,,
top of the tire tipped in towards the engine and the rim rubbed on the zerk fitting and I came to a slow stop with my ebrake .... I thought it was a tierod
so I didnt hit the brake pedal..luckily no one was beside me ....

I was riding around one hot weekend day in the 80's with my buddy in his 72 442 and we just got off the freeway
coming back from Alki beach on puget sound ,west seatte cruisin for a couple hours , came blazin back to
Redmond Wa and thought we would run thru Marymoore park and see who was hangin out
2nd speed bump in the park and "twang" ,,, right front side of the car drops ,,,, bottom u joint sheared off... at 5 mph .... tire bent the fender

whew ..... alot of people havent been as lucky as us ....

Scott

[nUcLeArEnVoY]

Originally Posted by Scott Thelander

WOW
you are very lucky .... it happened where it did ,,,,
mid 90's I had a 80 chev dually 2wd 10' Lance camper and a 14' aluminum boat n trailer behind
430 am monday morning on my way back from 6 days camping eastern washington fishin alta lake and columbia river and on my way to work
getting ready to take my exit home .. turn the blinker on and my truck makes a thump sound and then grinding ,,, looses steering basically and sends me
right 2 lanes and into the grass median with a gentle right turn thankfully ,,,, the passenger upper ball joint had pulled out of the socket,,,,
top of the tire tipped in towards the engine and the rim rubbed on the zerk fitting and I came to a slow stop with my ebrake .... I thought it was a tierod
so I didnt hit the brake pedal..luckily no one was beside me ....

I was riding around one hot weekend day in the 80's with my buddy in his 72 442 and we just got off the freeway
coming back from Alki beach on puget sound ,west seatte cruisin for a couple hours , came blazin back to
Redmond Wa and thought we would run thru Marymoore park and see who was hangin out
2nd speed bump in the park and "twang" ,,, right front side of the car drops ,,,, bottom u joint sheared off... at 5 mph .... tire bent the fender

whew ..... alot of people havent been as lucky as us ....

Scott

Absolutely crazy.

What were you able to attribute the failures to? Same as with mine; out-of-round spindle taper holes?

My theory is that when the lower ball joints were replaced in the past, somebody didn't tighten them enough which made for an improper interference fit, allowing movement of the stud which progressively rounded out the hole. A proper tapered interference fit is solid and totally immobile, and is where all the strength in the balljoint is where it fastens to the knuckle, so it should ideally never even give opportunity for the mounting hole to wear or go out-of-round. Steering knuckles don't just "wear" or go bad. Somebody put on my ball joint wrong.

And yes, we are super lucky. Besides a scratch on the back of my wheel which can't even be seen, I didnt' sustain any damage. Even the fender is unscathed.

[Sirrotica]

50 years of wrenching here, and 12 years of racing dirt track cars, more years wrenching on others dirt track cars, (nothing loads the front suspension harder than throwing a car into a corner and loading the RF suspension in a corner).

Two things I know of that will cause the ball joint stem to snap off:

1) You already touched on one, leaving the castellated nut loose, wallowing out the hole. Tightening it up will not help as the taper of the 2 surfaces no longer match, and the stem will only make contact at a much reduced surface area, causing it to later fail.

2) Hitting a curb with enough force to bend the spindle forcing the ball joint to bind when turning. I once did this to my own car (1973 Grand Am, 30,000 miles) during a snow storm, the ball joint stem didn't break immediately, it broke a few weeks later. I assumed I fractured it when I hit the curb. I installed a new ball joint that broke again in a similar time frame, 2-3 weeks. This time I changed the spindle, and the ball joint. I owned the car for 5 more years without any further problems.

I examined the spindle and even compared it to the one I replaced it with. Visual inspection showed not enough bend to see with the eye. I'm sure if I measured all the specs it would have shown where it was bent.

It's not a common problem for a healthy ball joint to break, I've seen plenty of worn out ball joints/tie rod ends pull out of the sockets due to worn away metal, due mostly to negligence, or high mileage. When the stud snaps off you may have unknown/unseen damage from curb contact.



From previous experience, GM started using a larger outer wheel bearing on some of their cars in 1979. I once tried to put a rotor and wheel bearings from an early second gen on a 79 spindle, and found out the outer wheel bearing size had increased.

[nUcLeArEnVoY]

Originally Posted by Sirrotica

50 years of wrenching here, and 12 years of racing dirt track cars, more years wrenching on others dirt track cars, (nothing loads the front suspension harder than throwing a car into a corner and loading the RF suspension in a corner).

Two things I know of that will cause the ball joint stem to snap off:

1) You already touched on one, leaving the castellated nut loose, wallowing out the hole. Tightening it up will not help as the taper of the 2 surfaces no longer match, and the stem will only make contact at a much reduced surface area, causing it to later fail.

2) Hitting a curb with enough force to bend the spindle forcing the ball joint to bind when turning. I once did this to my own car (1973 Grand Am, 30,000 miles) during a snow storm, the ball joint stem didn't break immediately, it broke a few weeks later. I assumed I fractured it when I hit the curb. I installed a new ball joint that broke again in a similar time frame, 2-3 weeks. This time I changed the spindle, and the ball joint. I owned the car for 5 more years without any further problems.

I examined the spindle and even compared it to the one I replaced it with. Visual inspection showed not enough bend to see with the eye. I'm sure if I measured all the specs it would have shown where it was bent.

It's not a common problem for a healthy ball joint to break, I've seen plenty of worn out ball joints/tie rod ends pull out of the sockets due to worn away metal, due mostly to negligence, or high mileage. When the stud snaps off you may have unknown/unseen damage from curb contact.



From previous experience, GM started using a larger outer wheel bearing on some of their cars in 1979. I once tried to put a rotor and wheel bearings from an early second gen on a 79 spindle, and found out the outer wheel bearing size had increased.

Are you replying to me or the previous poster? Because my failure didn't involve the stem snapping off, and it occurred as I was just making a slow but sharp left turn on flat pavement at a gas station. I've never curbed the car, or run over a curb or anything like that since I owned it, but it's true that I certainly can't rule that out from a past owner. I've only owned the car for 1.5 years and have never touched the ball joints. Your first point you mentioned is my theory as to what happened in the past during previous ownership.

What happened with mine is that it just popped out of the steering knuckle. The entire stud was intact, though the threads were wiped/stripped and the cotter pin was sheared through (piece of it was still inside the hole in the stud). I found the castle nut lying inside the control arm. Clearly the force of the failure caused the castle nut to violently walk off, or even just force its way off the stud regardless of the threads, wiping them on the way.

And yep, you're right, starting in '79, the knuckles incorporate a spindle using a slightly larger outer wheel bearing. The ones on my car are from an '80-81 as far as part numbers are concerned, which also had the wheel bearing change incorporated, and so they could still be the originals.

I attached some pics I took of my failure. I can't think of any other reason this type of failure would occur other than an egged-out hole on the spindle, therefore a compromised taper fit. You can see in the photos that there is some slight out-of-roundness to my spindle hole where the ball joint popped out, and even that amount is enough to compromise it. Another thing I noticed is that the threaded part of the stud on the ball joint that failed on me is longer and has more threading than the new ACDelco 45D2026's I just got in today.

This is why I'm trying to find a brand new driver side spindle to complement the NOS passenger one I have coming in tomorrow. Sadly, I'm not having much luck. A member on a FB group is selling me a used driver side one that he sent me plenty of photos of and it looks good and serviceable, so fingers crossed. For all I know, the driver side one I have on there now is just fine since this failure occurred on my passenger side; I won't know until I remove it. But I'm counting on it to be compromised if the replacement ball joint in the driver side was installed in the same manner as the passenger side that failed on me. Like I said, this shouldn't be an issue with a properly installed ball joint. For all intents and purposes, you don't really even need the castellated nut, it's only there to hold tension on the taper interference fit.

[Sirrotica]

Another possibility is, that someone overtightened the nut, stripped it out, put the cotter pin in it and sent it out the door. When it started working around in the spindle, it failed. The nuts are much softer material than the stud is, and stripping the threads is entirely possible if someone has no idea of how tight it needs to be. Or they keep tightening the nut to get the cotter pin through the small hole. There are people out there that shouldn't be allowed to own tools......

I definitely have seen the nuts stripped out before, precluding a failure. I've also seen someone try to salvage a spindle by putting a fresh nut, and a washer on a worn out spindle, and ball joint stud, so they could pull the stud further into the worn out hole..........

I know you probably don't know this, but in the oval track world the subframes of F body cars are used in chassis construction of race cars. If they're stout enough to survive dirt track usage, they're plenty strong for street usage. I used to run a 71 Firebird in the street stock class at the local speedway, no front end problems whatsoever.

When the parts are as they should be, they will take an unbelievable amount of stress, as I pointed out about how hard you load the RF suspension on a oval track car. It's like a chain, the weakest link will show up when stressed.

I wouldn't be too worried about a used spindle on your car, the one on the other side is used too........ Just think of it as pre tested.....

Unless they're curbed at some point, or a wheel bearing fails, spindles are very trouble free for the life of a car.

[67Fbird]

car-parts.com
$50 all day long. In fact you might as well do the 1LE 12" upgrade

[nUcLeArEnVoY]

Originally Posted by Sirrotica

Another possibility is, that someone overtightened the nut, stripped it out, put the cotter pin in it and sent it out the door. When it started working around in the spindle, it failed. The nuts are much softer material than the stud is, and stripping the threads is entirely possible if someone has no idea of how tight it needs to be. Or they keep tightening the nut to get the cotter pin through the small hole. There are people out there that shouldn't be allowed to own tools......

I definitely have seen the nuts stripped out before, precluding a failure. I've also seen someone try to salvage a spindle by putting a fresh nut, and a washer on a worn out spindle, and ball joint stud, so they could pull the stud further into the worn out hole..........

I know you probably don't know this, but in the oval track world the subframes of F body cars are used in chassis construction of race cars. If they're stout enough to survive dirt track usage, they're plenty strong for street usage. I used to run a 71 Firebird in the street stock class at the local speedway, no front end problems whatsoever.

When the parts are as they should be, they will take an unbelievable amount of stress, as I pointed out about how hard you load the RF suspension on a oval track car. It's like a chain, the weakest link will show up when stressed.

I wouldn't be too worried about a used spindle on your car, the one on the other side is used too........ Just think of it as pre tested.....

Unless they're curbed at some point, or a wheel bearing fails, spindles are very trouble free for the life of a car.

Agreed, for sure.

Let me pick your brain... what is your recommendation for installing the ball joints? Just follow the service manual? Service manual states to torque the castle nut to 87-lb-ft, and if it doesn't meet the cotter pin hole, tighten until it does (and to NEVER back it off to meet the hole) to a max of 110 lb-ft. Should I just follow that? What happens if there is too little threading to reveal the hole by that torque-spec? What happens if there's too much threading and I can't even bottom out the castle nut without passing the cotter pin hole? There's too much variation here, and I'm counting on these new ball joints made 45+ years later to meet the same specs and dimensions as the originals... it's why I didn't cheap out and spent the premium on the ACDelco ones, but you never know. Maybe I'm overthinking it. I just don't want another failure like this again, and I want to do this right.

Also, how can I TEST FIT the interference fit/taper between the ball joint and knuckle mounting holes? Just shove the ball joint stud in there and try to rock it around, and if it doesn't move at all and only the threaded part of the stud is poking out the other side, it's good?

[Sirrotica]

Originally Posted by nUcLeArEnVoY

Agreed, for sure.

Let me pick your brain... what is your recommendation for installing the ball joints? Just follow the service manual? Service manual states to torque the castle nut to 87-lb-ft, and if it doesn't meet the cotter pin hole, tighten until it does (and to NEVER back it off to meet the hole) to a max of 110 lb-ft. Should I just follow that? What happens if there is too little threading to reveal the hole by that torque-spec? What happens if there's too much threading and I can't even bottom out the castle nut without passing the cotter pin hole? There's too much variation here, and I'm counting on these new ball joints made 45+ years later to meet the same specs and dimensions as the originals... it's why I didn't cheap out and spent the premium on the ACDelco ones, but you never know. Maybe I'm overthinking it. I just don't want another failure like this again, and I want to do this right.

Also, how can I TEST FIT the interference fit/taper between the ball joint and knuckle mounting holes? Just shove the ball joint stud in there and try to rock it around, and if it doesn't move at all and only the threaded part of the stud is poking out the other side, it's good?

I have never used a torque wrench to tighten the nut. If your unfamiliar with how tight it needs to be, then it maybe a good idea. I learned my craft from my father, and back 50 plus years ago most mechanics tightened fasteners by feel, I can't remember anyone using a torque wrench for everyday jobs in all the garages and dealerships I've worked at, torque wrenches were reserved mostly for engine assembly work.

The failure was due to the nut threads failing, the spindle was ruined by the nut either being left loose, or it was over tightened. I would side towards overtightening. One other possibility was the nut was defective when made, but it was not examined upon assembly, and used as it was.

Whatever the problem, it's fairly rare to see what happened in your case.

I'd make sure the parts and fasteners are good with a visual, torque the nut if you don't feel confident in your knowledge to know when it's in the correct range. Make sure when assembled there is still thread on the stud below the nut so the taper can be seated, and not run out of thread, and send it down the road. I know you're snake bit from this incident, but it's not by any means a common occurrence.