Author Topic: Cam Bolt and Upper Control Arm Bushing Fit  (Read 674 times)

Offline solarguy

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Cam Bolt and Upper Control Arm Bushing Fit
« on: March 28, 2017 - 02:48:34 PM »
I just received a partial order from rock auto for my front end rebuild.  The moog 8243a cam bolts and moog k408 regular bushings.  The shank on the cam bolts fits through the bushing inner sleeve very loosely, like the next size up on bolt size would be more correct.  A good 1/8 to 3/16 sloppy fit.  This just doesn't seem right.  Car is still together so I can't check existing setup.  Did I get sent the wrong parts? 

EDIT: I called moog tech and the blue prints for the parts show a clearance  factor between bolt shank and bushing sleeve of .140.  Wont this lessen the adjustment available and wont the control arm be able to move in and out .140 on the bolt?  They say part blueprint unchanged for years and say parts are correct. 
« Last Edit: March 28, 2017 - 03:21:36 PM by solarguy »




Offline burdar

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Re: Cam Bolt and Upper Control Arm Bushing Fit
« Reply #1 on: March 28, 2017 - 04:35:13 PM »
When the bolt is tight, the rubber of the bushing is the only thing that moves(flexes).  The outer bushing sleeve is pressed into the control arm.  The inner sleeve is held stationary by the body.  The bolt squeezes the body together against the outer bushing sleeve.

Since the rubber is the only thing that flexes, the bolts shouldn't be tightened unless the car is at the proper ride height.
« Last Edit: March 28, 2017 - 04:38:43 PM by burdar »

Offline 73_Cuda_4_Me

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Re: Cam Bolt and Upper Control Arm Bushing Fit
« Reply #2 on: March 28, 2017 - 04:37:26 PM »
The eccentric washers on each end of the bolt sit in a U-channel on each side of the UCA, and hold everything in place. They are keyed on each end with no slop to bolt, and just fit inside the u-channel on either side of UCA... when bolts are tight, so is UCA...
1973 Plymouth Cuda BS23H3B567783

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Offline solarguy

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Re: Cam Bolt and Upper Control Arm Bushing Fit
« Reply #3 on: March 28, 2017 - 05:03:41 PM »
ok so  I'm sitting here at my table putting the bolt through the bushing, the fact that the inner bushing sleeve is measuring .570 diameter and the bolt shank is measuring .490 diameter, leaving .08 play, that is ok?  I understand how it mounts in the car I just expected the fit between cam bolt and inner sleeve to be much tighter. 

Offline 69bcuda

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Re: Cam Bolt and Upper Control Arm Bushing Fit
« Reply #4 on: March 28, 2017 - 09:52:45 PM »
Picture of an A-body bushing end cap. This is the end for the bushing, should be two for each. The hole in it is .500" which the bolt would fit as designed.
 

 

Offline solarguy

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Re: Cam Bolt and Upper Control Arm Bushing Fit
« Reply #5 on: March 29, 2017 - 08:36:43 AM »
Picture of an A-body bushing end cap. This is the end for the bushing, should be two for each. The hole in it is .500" which the bolt would fit as designed.


now we're getting warmer as towards my question.  The inner diameter of the sleeve on my new bushings in .570 and the cam bolt shank is .490 resulting in a very loose fit.  Looking at your pic, If I stuck the cam bolt through the end of that bushing, the bolt slides through with .08 clearance all around which seems excessive.  I'm putting an .490 bolt through an .570 sleeve. 

Offline 69bcuda

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Re: Cam Bolt and Upper Control Arm Bushing Fit
« Reply #6 on: March 29, 2017 - 11:29:13 AM »
solarguy, the caps go on the ends of the bushing. Your 1/2" cam bolt (.490") would have .010" clearance in the end cap holes. Don't your E-body bushings have these?
The arrows point to the caps. The top one is in the sleeve and the bottom one has come off.

Offline solarguy

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Re: Cam Bolt and Upper Control Arm Bushing Fit
« Reply #7 on: March 29, 2017 - 11:44:06 AM »
solarguy, the caps go on the ends of the bushing. Your 1/2" cam bolt (.490") would have .010" clearance in the end cap holes. Don't your E-body bushings have these?
The arrows point to the caps. The top one is in the sleeve and the bottom one has come off.

I don't know for sure as I haven't torn into it yet.  Some of the new parts arrived yesterday and I was just mocking up what came. New bolts don't come with caps.  New bushings don't come with caps either.   From playing around with the parts, it just seems like the bolt fit would be tighter going through the bushing.  I guess I should wait until I tear it down to see what's what. 

Thank you everyone for the replies. 
« Last Edit: March 29, 2017 - 11:51:39 AM by solarguy »

Offline 69bcuda

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Re: Cam Bolt and Upper Control Arm Bushing Fit
« Reply #8 on: March 29, 2017 - 12:16:01 PM »
Don't toss the old caps!