Current compressor situation

I swapped out my front gear housing this week, and by the power of suggestions of the professionals I decided to replace my air compressor. Much to my surprise it is not as simple as I thought it would be. Unless someone hear has some further advice.
I have the N500 compressor on my 3116, which is not an available compressor any longer, like the google parts doc shows it crosses with the new Haldex EL16280, which is not available anywhere I can locate, I even called Haldex directly and they have no inventory with no ETA of any to be made.
Their is next the Midland reman 107981x which is available through Napa and I purchased one, but the spline drive output of the compressor is larger and does not fit my power steering pump (unless I can change it????? Which I would if I could find one).
And the TruckPro unit I have not been able to locate any.
So this leaves us with one option, a rebuild service. I located a good company in Oregon, I just don’t have the time to wait at the moment to ship it there, have the work performed and have it shipped back.

This is is a cry for help/PSA for those looking to keep their compressor in tip top shape. My compressor is functioning fine BUT the known proble, is that these compressors have a short life span and when they get worn they get out of balance and can cause the gear housing to crack. And that is a decent PITA to replace. Take my word for it.

Thanks.

Bendix 125 9562

Or one of these

Ornduff said:

BUT the known proble, is that these compressors have a short life span and when they get worn they get out of balance and can cause the gear housing to crack.

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I don't think there is much evidence to support that statement being true. Even just reading these forums for years shows that we are not getting even infrequent posts of people's air compressors going out. Be careful tossing around phrases like "known problem".

Awesomeness said:

I don't think there is much evidence to support that statement being true. Even just reading these forums for years shows that we are not getting even infrequent posts of people's air compressors going out. Be careful tossing around phrases like "known problem".

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There are other worlds outside of this that the 3116 is used and yes it is a problem mostly from worn engine mounts that causes excess vibration and the air compressor mounting bolts vibrate loose and cause it to crack in the housing. It is a known problem on the 3116s for that to happen. It is just that these trucks do not see as many miles or hard usages as the Kodiaks and other medium duty trucks to wear stuff out like they do

It also is an issue when ignorant techs do not put all the correct brackets back on particular motors and that causes a weak link somewhere else

simp5782 said:

There are other worlds outside of this that the 3116 is used and yes it is a problem mostly from worn engine mounts that causes excess vibration and the air compressor mounting bolts vibrate loose and cause it to crack in the housing. It is a known problem on the 3116s for that to happen. It is just that these trucks do not see as many miles or hard usages as the Kodiaks and other medium duty trucks to wear stuff out like they do

It also is an issue when ignorant techs do not put all the correct brackets back on particular motors and that causes a weak link somewhere else

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I'm aware of that, to which the solution is simply to check the bolts and Loctite them. He's just saying "I know these air compressors break a lot", which simply isn't true.

As an aside, few people stop to think about how many cases are needed to start rumors of "known problems", "poor design" issues, etc.? It's actually incredibly small. In some of the studies we've done, we're talking less than 1%. In the internet age, even smaller. You get a handful of stories that line up, suddenly every shadetree-engineer thinks they've diagnosed the same thing, and voila... it's a poorly engineered design flaw that is a known problem on all these models. People really need to be careful throwing that kind of accusation around, and people need to be skeptical of it when they hear it. That's not to say it isn't worth checking your bracket bolts, but replacing the whole air compressor because it's a "known problem" is pointless and wrong.

I apologize if I struck a nerve with that particular comment. My statement comes from discussions with individuals from the industry around the air compressors themselves. Not FMTV. I have spoken to a couple specific FMTV repair facilities and they specifically expressed the suggestion of rebuild or replace compressor as part of the procedure when replacing the damaged housing. Because these compressors become “out of balance” and can facilitate the failure of the housing. I believe my primary cause of cracking is the bolts backed out of the support bracket which is a more common occurrence I gather.

Ornduff said:

I apologize if I struck a nerve with that particular comment. My statement comes from discussions with individuals from the industry around the air compressors themselves. Not FMTV. I have spoken to a couple specific FMTV repair facilities and they specifically expressed the suggestion of rebuild or replace compressor as part of the procedure when replacing the damaged housing. Because these compressors become “out of balance” and can facilitate the failure of the housing. I believe my primary cause of cracking is the bolts backed out of the support bracket which is a more common occurrence I gather.

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He is not a tech and has never touched any CAT other than his own, or probably just stared at it more or less. I wouldnt let him bother you too much with what he doesn't know.. I am glad the site has an ignore list.

Ornduff said:

I apologize if I struck a nerve with that particular comment. My statement comes from discussions with individuals from the industry around the air compressors themselves. Not FMTV. I have spoken to a couple specific FMTV repair facilities and they specifically expressed the suggestion of rebuild or replace compressor as part of the procedure when replacing the damaged housing. Because these compressors become “out of balance” and can facilitate the failure of the housing. I believe my primary cause of cracking is the bolts backed out of the support bracket which is a more common occurrence I gather.

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That explanation just isn't possible. Short of breaking something off it, it cannot become out of balance. It's a rotating shaft and a couple pistons. There is no adjustable balancer or something inside that could come loose or move. You would basically have to break a piston off, at which point balance really isn't your problem.

Not the exact compressor, but similar in design. Try to look at it and find the part that would become imbalanced.


The support bracket coming off will break the front engine housing, but that's still not because the compressor is out of balance. It's because the compressor is then only supported by the front housing, while the engine and truck jump around.

I had a compressor on my A1 throw a rod.

I had a valve go through a piston
I finally found a compressor and rebuilt mine.

scottmandu said:

I had a compressor on my A1 throw a rod.

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Bringing a dead horse back to life here, we just recently had a rod failure on our compressor. Resulting in a massive oil leak that could have been much worse if we didn't have people behind us alert us that we were spraying oil. New compressor on order from a company out of Oregon.