Control Arm question- repair, replace or reinvent ?
 

the first 1/2 inch of threads in 1 end of the upper control arm shaft are messed up. can this be cured by simply using a longer bolt when i reassemble- the original bolt barely reaches the good threads now but won't when the bushing is installed- or do you guys recommend i either replace the shaft or have the original one retapped ?

thanks-

The control arm shafts are relatively cheap and easily available. O'Reilly has the complete kit (Moog #K6104) with the offset arm and bushings for $46.99 and I'm sure other places have them as well. The offset arm will give you a few degrees more adjustment which is usually a good thing. I wouldn't mess with the old one... they're too hard to get to if your "fix" doesn't work.

Steve

I would see if you can run a tap into it and fix it. That would be a lot easier than tearing it apart, assuming it is still assembled on the car. The lower a-arm threads are 7/16-20 and the uppers are 3/8-24. I don't see any interference problems doing this on the car. You can use a socket adapter on the tap if needed. These are available from the tool stores where I live. Occasionally you find a regular six point socket that fits. You only need 1 1/2 times the bolt diameter in thread engagement to achieve maximum strength. Be sure and put some oil on the tap before you start. Good luck. Mike

I would replace it. The upper is easier too get off due to the weight of the car being on the lower control arm assembly. If you have the suspension all apart, replace both of them, it's simple long term safety.:cheers: Dennis

Replace it - that's the last place you want questionable threads; that's a blind hole that's bottom-tapped already, and re-tapping it isn't going to gain you anything. :thumbs:

67*427 wrote "The offset arm will give you a few degrees more adjustment which is usually a good thing."

can you guys explain this to me a little more to clue me in ?

thanks-

Ryan22,

The offset arms are made to move the upper "A" frame toward the outside of the car. Often on older cars, there has been enough sag over the years that the control arm needs to be moved toward the outside of the car to achieve the desired alignment specs and the offset arms allow that. They do not change the "look" of the car under the hood because the "A" frame is only offset a little but it all helps. If you get a parts guy to let you look at one, you'll see the offset.

Did that help?

Steve

Stock shaft on the left, offset shaft on the right. :thumbs:

So, with regard to the final wheel alignment specs (WITH RADIALS) where you are trying to achieve more caster, would these allow you to achieve say 2.5* + with some room to spare??? My upper arms are shimmed to the max now at the rear shim spot. Would it be worth changing the shafts?? Interesting replies to this post. :cheers: Pilot Dan

Nope, because both ends of the shaft are offset - all it adds is camber adjustment capability; to get more positive caster, you need only the rear of the shaft offset inboard, or only the front of the shaft offset outboard (to move the upper ball joint rearward). :thumbs:

Steve & John- thanks for explaining the offset shaft.

if i use the offset shaft- i'll need to adjust the number of shims i have on the control arms, correct ?

also is it necessary to replace both upper A arm shafts rather than going to the offset style on just one side ?

thanks again-not too many more questions i promise, i'm gettin up to speed.:thumbs:

Thanks John.:flag:

Putting this in "front suspension for dummies" language for me because all my shims are the rear with none up front, what is it I need to have a more balanced alignment on the upper A-Arm :bigears

When I had my alignment done by a good mechanic on good equipment (laser tv) but who was unfamiliar with our cars he thought that maybe my shim situation reflected that my lower arm was bent because all the ball joints, bushings etc were brand new.

Do I need a new upper A arm?.......... I still have the motor out so now is the time to do whatever I need done.

He felt that if I hit a hard such as a hole, curb or a wheelstand on slicks that all those shims would go flying out :eek:

Doug

Maybe. Suppose you have 4 shims in the front and 6 in the rear now. With the new shafts you need 2 front and 4 rear to get the same camber and caster. If you install 0 front and 6 rear, you'll get the same camber and more caster. Maybe.

Ryan22,

You CAN replace only one arm if need be but typically, both are replaced. Yes, you will typically need more shims. I just had my '67 aligned yesterday with 1.5 degrees of caster and I have probably 1/2 inch or so of shim on the rear of both arms. Drives VERY nice!

Steve