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Discussion Starter #1
I have a 2008 Chevy silverado 3500 HD with a 10" CST lift, that the lower ball joints keep fracturing the uniball pins. The lower control arms appear to be custom fabbed and have a FK 16T uniball bearings and a uniball pin that I have not been able to find other than getting one fabricated. I have now broken two of these pins one on passenger and one on the driver side.

I have pictures if anyone is interested.
 

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in.

yea lets see this rig
 

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Cut that stupid fucking lift off and put a straight axle in it.

You're in the wrong place...

:shaking:
 

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You're gonna get torn in half here...
 

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Discussion Starter #8
Ok so I am just looking for some help not looking to hang my dick out and see how big everyone else's is. I bought the truck as you see it for a price that I couldn't turn down. I want to get the truck running to where I don't have to worry about breaking shit running down a straight paved road.
 

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Ok so I am just looking for some help not looking to hang my dick out and see how big everyone else's is. I bought the truck as you see it for a price that I couldn't turn down. I want to get the truck running to where I don't have to worry about breaking shit running down a straight paved road.
Yep then either lower it or stick a straight axle in it. The real question is if you're having these pins made, are they being made better than the one that broke? Perhaps the one you already replaced isnt going to break and you simply need to replace the other.

Maybe you should just get another one made, pull out the one you already had made and replaced and send them out to get them made in chomo, have them heat treated and never worry about it again.

If they still break you have suspension design issues that arent properly distributing forces OR the joint is simply under designed in size and needs to be stepped up to something beefier, but I would bank on the first thing.

Technical enough for you? :flipoff2:
 

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O yeah and Im gonna take a stab and say the "lift company" is having said pin manufactured for them considering your typical uniball would take a large bolt with misalignment spacers or a normal sized bolt with high alignment spacers depending on the angle needed.

If you really want help you gotta take some better pictures of the control arm and how that broken pin mounts in the knuckle. I see the pin but god damn the other pictures are dark.
 

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Discussion Starter #12
Much better... I actually did have the pins made out of a little higher grade metal 4140 and not heat tempered so it will be a bit more elastic. The FK bearing will allow for a bit more thickness on the pics if I get the ring stop turned with the pin instead of sliding over the pin.

I was really hoping that someone else has possibly run into this problem and could offer some advise. All the ford and dodge peeps tell me to rip out the IFS and put a straight axle but the engineer in me wants to figure out how to make this work.
 

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Much better... I actually did have the pins made out of a little higher grade metal 4140 and not heat tempered so it will be a bit more elastic. The FK bearing will allow for a bit more thickness on the pics if I get the ring stop turned with the pin instead of sliding over the pin.

I was really hoping that someone else has possibly run into this problem and could offer some advise. All the ford and dodge peeps tell me to rip out the IFS and put a straight axle but the engineer in me wants to figure out how to make this work.
Well you landed in a place that this really isnt the crowd for IFS lift kinda stuff. We're all for the most part function over the blingy form that is street trucks but to each his own I guess.

So lets figure this mounting this out. The taper on the broken shaft is mounting where the balljoint stud used to previously mount in the knuckle correct?

Then the stud part below it thats breaking is mounting through the misalignment spacers in the uniball? Is that correct?
 

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Discussion Starter #14 (Edited)
I posted some better pictures with more exposure. The uniball pin has two slip over stoppers that allow the bearing to rotate without limiting the bearing rotation if that makes sense. The pins show rust on a portion of the break so I am certain that the pin cracks and then once it is cracked enough it just shears off.

A couple of the pictures are of the drivers side that I already replaced and is fully assembled the passenger side is the shots without the tire.

http://imageshack.us/g/1/10007382/
 

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I posted some better pictures with more exposure. The uniball pin has two slip over stoppers that allow the bearing to rotate without limiting the bearing rotation if that makes sense. The pins show rust on a portion of the break so I am certain that the pin cracks and then once it is cracked enough it just shears off.

A couple of the pictures are of the drivers side that I already replaced and is fully assembled the passenger side is the shots without the tire.
Ok I see it now. Its just what I was thinking it was.

The issue is you've got alot of angle in single sheer. The "stoppers" you're referring to are known as misalignment spacers. They do just as you described and let the joint flex beyond the diameter of the center bore of the uniball.

Whats your bumpstop situation? Id be willing to bet that on too much droop or stuff this is your weak point of the suspension trying to continue traveling past the given amount of flex in that joint. If thats the case you have a design issue and you will NEVER fix it by building that piece better.

A few given solutions may be to run a high misalignment spacer which will step down the through bolt size and require new machine but will allow for way more flex in the joint. Im no engineer so I couldnt begin to tell you what you need for a bolt size going through that setup but you're already breaking shit and for all intensive purposes loosing a balljoint while driving, and thats dangerous.

You could uncrank the torsion bars which should reduce the preloaded angle on balljoint too.
 

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Discussion Starter #16
Thanks for the advise I will work with my machinist and see if maybe we can come up with something to step this thing down and get that lower control arm more aligned, which will lower the tension on the joint significantly I think.

Like you said I am already breaking shit but just very lucky that this has happened while I was at lower speeds and able to pull off to the side of the road. Who knows maybe I can put a damn patten on the piece and get rich off of stubborn chevy owners like myself that want to raise their trucks and not put a straight axle in.
 

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Thanks for the advise I will work with my machinist and see if maybe we can come up with something to step this thing down and get that lower control arm more aligned, which will lower the tension on the joint significantly I think.

Like you said I am already breaking shit but just very lucky that this has happened while I was at lower speeds and able to pull off to the side of the road. Who knows maybe I can put a damn patten on the piece and get rich off of stubborn chevy owners like myself that want to raise their trucks and not put a straight axle in.
I would seriously check out your preload angle too. Everything might be setup fine you just need to bumpstop you're droop. I guarantee its happening when the wheel falls out and droops really fast. Any abnormal hard BANGS when hitting a pothole other than normal pothole noises?

Jack the truck up from the frame to droop the wheel all the way out and see if that thing is riding against the control arm or side of the uniball, bet it is.
 

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Shorten the limiting straps. I would highly suggest you let the front down some. I know you probably dont want to hear that but dropping that front end 1-2" by lowering the torsion bars would do wonders for your range of motion with wheel travel.
 

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Discussion Starter #20
Shorten the limiting straps. I would highly suggest you let the front down some. I know you probably dont want to hear that but dropping that front end 1-2" by lowering the torsion bars would do wonders for your range of motion with wheel travel.
To be honest with you I don't really care about losing 1-2" in lift to get a safer ride.
 
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