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[C1] 3rd Arm Help

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Old May 9, 2022 | 11:45 PM
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Default 3rd Arm Help

I have a stock 1959. I noticed while on the lift I could rock the front wheels forwards and back about a half of an inch. Upon closer inspection, I found the play was mainly in the 3rd arm. I really haven't found a lot of info about this issue. I purchased all the parts to rebuild the unit and did. I found it really did nothing, and there was still play in it. I found the shaft would go up and down on the old and new one. Someone had installed a shim on the old one at the bottom that did nothing. I made a shim to go on the top of the pin to take up the slack and it did, but once back together it had just a little less play but still plenty in the wheels.

Does anyone have experience with this issue?
Thank you.
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Old May 10, 2022 | 06:48 AM
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Might also want to check your king pins/
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Old May 10, 2022 | 08:31 AM
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The ONLY thing that is replaceable on the center steering arm is the bearing inside the joint. Of course, the tie rod ends are replaceable.
The bearing should be a snug fit in the arm and the big bolt should be a snug fit in the bearing. Essentially no play between the arm-bearing-bolt.

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Old May 10, 2022 | 09:35 AM
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Thanks for the info. I think the lip on the cup of the arm has worn down over time, so someone put a shim between the cup and the arm to take up the slack, but the shim had worn away over time.

Does anyone have a arm that they can measure how much material should be on the lip of the cup where it contact the bracket bolted to the frame. Mine doesn't seem to have heady any material.

While I'm asking, does anyone have a good arm with the cup they would like to sell?
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Old May 10, 2022 | 11:31 PM
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Here is how I fixed the problem permanently on mine. The smallest amount of looseness in the bearing housing translates into magnified up and down movement at the tie rod connection. By doing this fix it takes out all looseness except that that is built into the bearing as running clearance. It was a poor engineering design, but one we can live with if we minimize the effect by utilizing this fix. After you install the bearing you snug down on the set screws to force the bearing against the snap ring and thereby removing any movement of the bearing within the housing. I did this about 15 years ago and it is still as tight as it was right after I did it. Follow the pictures. Self explanatory. Use a high speed steel drill and tap as the forging is tough. Put RTV on top side of set screws when done to exclude any moisture.













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Old May 10, 2022 | 11:40 PM
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Default Update

Thanks for the thread. When I took it all apart to rebuild, someone had put a shim at the bottom between the cup lip and the bracket mounted to the frame. I'm guessing where these 2 surfaces meet, the cup has become worn. I would love to know what the lip the felt dust ring recess goes around is on a good one to see if mine is worn that bad.

Thanks again
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Old May 11, 2022 | 01:14 PM
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A picture of yours would be helpful to see what is going on with it.
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Old May 11, 2022 | 04:57 PM
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Default Final info until I buy a new 3rd arm.

I installed the shim back between the bearing cup and mounting bracket and it took all the slop out of the bearing area. I'm thinking my 3rd arm is definitely worn to the point of being no good. Once I get the new one, I will update the thread.

Sorry no photos and I've got it put back together and driving around.
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Old May 11, 2022 | 11:30 PM
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Sent you a PM.

Jay
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