Ar Compressor Failure

o1marc · 09-07-2018, 01:40 PM

So the compressor started to squeal on the way home from purchasing the bus. Got worse before something critical sounding happened and the noise went away. After snooping in the engine bay I determine the pump had seized and broke the belt. It was a major job to get this pump out. Finally popped it out today and removed the bracket exposing the bottom end. As I pulled the bracket away I saw a big pile of metal shavings, the remnants of the bearing. I then noticed the broken and bent rod bolt sitting in the bottom. Peering up into the box made things pretty self explanatory. Now I need to pull the cap and see if the crank is salvageable with new bearings and bolts/cap.

somewhereinusa · 09-07-2018, 03:15 PM

I would just get a recon compressor, they aren't too expensive, although your core might not be anything they would want. Alternative would be junk yard Shouldn't be too hard to find. Here's the first search I did.

https://www.heavytruckparts.net/sear...66&PartID=5220

Anyplace that sells truck parts should be able to help. If you have a Truckpro near I've bought compressors from them.

I would think the parts to rebuild, if you can find them, will cost as much as a recon.

Took another look at that bottom picture, sure don't look like it had much, if any oil getting to it. They get oil from the engine.

o1marc · 09-07-2018, 04:45 PM

Quote:

Originally Posted by somewhereinusa

I would just get a recon compressor, they aren't too expensive, although your core might not be anything they would want. Alternative would be junk yard Shouldn't be too hard to find. Here's the first search I did.

https://www.heavytruckparts.net/sear...66&PartID=5220

Anyplace that sells truck parts should be able to help. If you have a Truckpro near I've bought compressors from them.

I would think the parts to rebuild, if you can find them, will cost as much as a recon.

Took another look at that bottom picture, sure don't look like it had much, if any oil getting to it. They get oil from the engine.

If you consider $400 not too expensive. Most want $500 core charge on top of that. My local auto parts store will sell me one for $276. The oil drains back to the pan when it's not running, it's been sitting for 3 weeks.

o1marc · 09-07-2018, 05:40 PM

Quote:

Originally Posted by somewhereinusa

I would just get a recon compressor, they aren't too expensive, although your core might not be anything they would want.

You had me worried about my core, so I went and disassembled it. I bent the locking tab over and started to unscrew the remaining rod bolt, it sheared off as I did. It doesn't look as bad as I imagined, the rod cap is bent and needs replacing as well as the fubar bearing that did it's job and took the abuse. A couple more rod bolts, or a new rod assembly and this pump should be good to go. Your link was for compressors for a DT466. The pump that went south is on the other bus with the DD6.2.

o1marc · 09-07-2018, 06:00 PM

Quote:

Originally Posted by somewhereinusa

I would just get a recon compressor, they aren't too expensive, although your core might not be anything they would want.

Delete duplicate post.

brokedown · 09-07-2018, 06:39 PM

276 isn't awful if it gets that bus back on the road (aka back on craigslist)!

o1marc · 09-07-2018, 06:48 PM

Quote:

Originally Posted by brokedown

276 isn't awful if it gets that bus back on the road (aka back on craigslist)!

Back on CL next week hopefully. It was a major PITA to get that pump out and it's going to cost whomever buys it. $276 is a great price compared to everywhere I checked, was surprised to find it cheapest locally.

cadillackid · 09-08-2018, 06:58 AM

good thing that wasnt a gear driven compressor.. the damage couldve been a lot worse.. since its a bus for sale, go to a truck Junkyard, yank a compressor put it on and go.. the school bus yards around me often still have their belt drive compressors still attached..

-Christopher

o1marc · 09-08-2018, 10:46 AM

Quote:

Originally Posted by cadillackid

good thing that wasnt a gear driven compressor.. the damage couldve been a lot worse.. since its a bus for sale, go to a truck Junkyard, yank a compressor put it on and go.. the school bus yards around me often still have their belt drive compressors still attached..

-Christopher

You make it sound so easy. But this pump uses the big bracket as the bottom plate of the crank case and has attachments all over it for oil and coolant. I see a gazillion pumps out there and they all seem to be a bit different. I'm taking this to the parts store to match up exactly.

Mekanic · 09-15-2018, 04:28 PM

That crank in that compressor looks VERY DRY as far as lube oil is concerned.
Make darn sure the next compressor is getting the oil it needs or it will lock up in 5 minetes.

Dirtdoctor · 09-15-2018, 06:39 PM

Buy a recon unit- check the check valve and oil level and lines- could be s bad oil pump.

cadillackid · 09-15-2018, 07:47 PM

Quote:

Originally Posted by o1marc

You make it sound so easy. But this pump uses the big bracket as the bottom plate of the crank case and has attachments all over it for oil and coolant. I see a gazillion pumps out there and they all seem to be a bit different. I'm taking this to the parts store to match up exactly.

the school busses uses mostly similar compressor layouts.. and many of the compressor heads are universal and use NPT threads.. unused holes are filled with NPT plugs..

bottom plate pad mount is same for all belt driven compressors.. you just need a gasket.. the 4 hole mounting is the same..

compressor should have oil supply, oil, return.. typically the same on all belt drive..

then in the head you have coolant in / out.. this is generally moveable by way of which plugs you pull out and insert your fittings for coolant hoses..

air discharge.. will either be top or side... 90% of school busses use top discharge.. governor ports... the D2 governor typically mounts right to the compressor head.. and this is standard also... air intake is almost always in the same place...

the real differences are if you try asnd mount a gear drive compressor... they have a different body and shaft type as well as different port locations from what ive seen.. and of course not the 4 bolt pad mount..

-Christopher

o1marc · 09-15-2018, 08:18 PM

Makes me wonder now because when I test drove it at the school and drove it 22 miles home the oil pressure gauge didn't work, or so I assumed. Surely it didn't go 24 miles with no oil pressure at all. My truck certainly would have blown a motor in that mileage had it no oil pressure. Plan is to put it all back together with the exception of the fan belt and the oil feed line, crank the engine make sure I have oil pressure there before hooking it up and hooking the fan belt up.

Brad_SwiftFur · 09-15-2018, 08:44 PM

Perhaps it had minimal oil pressure? Just enough to keep the engine alive, but not enough to register or lubricate the air compressor?

o1marc · 09-15-2018, 09:01 PM

Quote:

Originally Posted by Brad_SwiftFur

Perhaps it had minimal oil pressure? Just enough to keep the engine alive, but not enough to register or lubricate the air compressor?

I always have an OP warning light set at 5-7 psi. I wonder now if I'm throwing good money after bad and I should just scrap this bus. I guess I'll put it together and hope like hell it has oil pressure. I can get it running have two guys fighting over it I think I'm going to be able to raise my price and then let them bid it up from there. That is if it's running.

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