Idler Arm Rebuild, pressing in bushings, Is this OK?

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andy72

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So I got new MOOG bushings from Rock Auto to rebuild my stock Idler Arm. 

The part numbers actually came from HEMIKILLER.

The MOOG #K8094 replacement bushing is noticeably larger than the stock bushing I pressed out of the Idler Arm.

The stock bushing measures 1.14 in diameter while the new MOOG bushing measures 1.18.

I was afraid of starting the process and getting a bushing stuck half way in or something.

My dads machinist friend says that this size difference is not that big a deal and that the bushing will pull in and compress.



Any thoughts?

 

cwalker509

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.040 interference is an awful lot to me but my experience is from aircraft. Maybe someone here can shed more light on this but I would not try to press that in.

 

andy72

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They sure didn't press right in, like say the front bushing on my leaf springs.

It stripped threaded rod trying to press it in.  No way in the vise.  Bent my vise handle with the aluminum pipe I put on it for leverage.

Took it down to the local auto repair guy and he pressed them in for $30.

Quick comment that I guess I never realized.  I never realized that, like the bushing on the right, when the center has all the little teeth on it that dig into the washer,

it is actually spinning the metal sleeve within the rubber.  The sleeve is tight to the washer and nut.

The bushing on the left however, just has the shaft going thru it.  The metal shaft on this side is spinning inside the metal sleeve.

How tight should this nut on the left be?  I assume tighten it down until you can't spin the shaft, then back it off a little. (followed by a tack weld on the nut)

The rubber protruding from both ends of the left bushing actually grabs the washer and makes the washer rotate under the nut.

This seems like it's going to be a lot of wear on the washer spinning under the nut?!

 
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My two cents worth. There is now way you ever have .040" press fit on anything...... 

A solid dowel pin of 5/8" will only have .0001" - .0002" press fit. I could see maybe .003" press fit on that thin wall bushing with rubber in it. Even roll pins only have .001" press and they can collapse. 

Heating and freezing the parts only changes maybe .001" - .002" which is nothing. If the original is .040" smaller and it was a press fit the new one has to be incorrect.

It is the wrong bushing in my opinion. 

I would back up and start over.

 
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Earlier, I just skimmed through this, not really taking much notice, but after re-reading it and David's reply, I would definitely agree with David that something is obviously wrong size wise. Even if the intent was to create more compression on the rubber inner barrel, .040" or 1mm is way off as far as interference fits are concerned. Normally .001" on a pin for instance, needs a press to push it in. .002" is a tight fit. I'm surprised the casting did not crack in this case. 

Is this a case of " Oh well, good enough, make it fit!" 

Geoff.

 
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NPD lists the Lower Idler Arm bushing as 3358-1 and is only $10.25 Just order the right one and fix it right. They do have a note in the catalog "Originally the P/S arm used a different upper bushing 3356-1 to improve return to center performance". The steering is not something you just randomly make changes to. Get the right part and be sure your are is the right one also. 

The whole assembly is 3355-1A and is $172.43. Page 119 or their 2020 edition catalog.

 
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NPD lists the Lower Idler Arm bushing as 3358-1 and is only $10.25 Just order the right one and fix it right. They do have a note in the catalog "Originally the P/S arm used a different upper bushing 3356-1 to improve return to center performance". The steering is not something you just randomly make changes to. Get the right part and be sure your are is the right one also. 

The whole assembly is 3355-1A and is $172.43. Page 119 or their 2020 edition catalog.
 That assembly jumped in price from my 2019 catalog. It's only 149.95 in there!

I looked for my NPD invoice from when I bought mine, can't find it right now, but the one I got and have posted on before, was the pro grade one, but I needed to slot the top hole upwards for it to fit. If I remember, it did say that somewhere in the packaging. The geometry was correct though and that's the important part. Again I posted on that with an attached sketch.

 

andy72

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Believe me... I was freakin out that I was gonna get a call from the shop I had press it telling me the arm broke, or the bushing got destroyed in the process.

I just wanted it done.

As I started with, that is the MOOG replacement...

I already had the MOOG replacement Idler Arm which is completely incorrect.

Oh, well.. it's installed...

 
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