HELP!! Removing a Cummins air compressor. [Archive] -

: HELP!! Removing a Cummins air compressor.

12-23-2006, 01:32 AM
Hows it come off? It's on my NT280B Serial # 311835. Original part to the truck and engine.

I got the fuel pump off and the 6 bolts that are on the compressor side of the piece that goes between the acessory drive and the compressor. Nuthin. So I took the 5 hard to get to bolts off at the acessory drive side and still wont budge. I been prying, hammering etc.

Managed to break the connecting rod in the compressor. I can see it but it still won't come off the engine. The compressor and the other part between the accesory drive and the compressor will spin slightly, an inch or so but it just wont come off.

My Cummins book says "Remove compressor" so it's no help.

Heres the only pic I have. Truck is at my work so I had to hitch a ride home.

12-23-2006, 01:46 AM
If the slip collar is froze on the nose of the compressor you have to pull the pulley off the accessory drive, pull the drive, and beat it til it comes apart. You may be buying an accessory drive also (under $500). Good luck and Merry Christmas!!...T

12-23-2006, 01:47 AM
How does all this come apart? is this something I can do in the truck?

12-23-2006, 02:14 AM
Looks like the older 1 piece shaft and housing. If it hasnít been updated to the later 2 piece compressor shaft and housing you are in for a ride.

Cummings made a kit to fix that but big $ unless you can find a used one.

The accessory drive pulley is pressed/pulled on the long compressor crankshaft with the 1 5/16Ē hex nut found on the front of the acc pulley. Problem is that itís all one piece crankshaft to the nut. You need a short puller or you have to pull the shroud and radiator. They make a puller for that, OTC i think.

If the crank is damaged might as well go to the late 2 piece compressor shaft kit. Right now Iíd say used would be the only way to go $ wise.:shrug:

12-23-2006, 02:34 AM
Iím looking around the net now. They used to be a lot of those out there but now unless you can find someone with an old truck and a good compressor I think Cummins would be a waste of time..

12-23-2006, 02:44 AM
sounds like its sized to the shaft or the weight is not helping. ????

12-23-2006, 02:49 AM
all I found were these 10%26hl%3Den%26lr%3D%26safe%3Doff%26sa%3DX 10%26hl%3Den%26lr%3D%26safe%3Doff%26sa%3DX

12-23-2006, 03:07 AM
I went to work and shot a pic. There are several places here that can rebuild it. I gotta get it to them tho.

12-23-2006, 03:19 AM
Yep, thatís the log shaft compressor. Cummins had so many complaints about RR on that unit that they later made a 2 piece unit so you could just unbolt the compressor housing and slide it off the splines.

It has to come off with the internal gear and shaft out of the accessory pulley. I changed my 71 Pete NTC335 drive over the first time I got into that mess. Best way is to find an old Cummins with the split shaft setup.

12-23-2006, 03:22 AM
So If I pull off the belts and somehow get the pully off I can atleast get it apart?

12-23-2006, 04:09 AM
Loosen the belts up and get an accessory drive puller. Once the pulley is off it will slide out the back with the shaft and gear. The pulley has a keyway and you will want to change that seal also along with the wear ring and new locknut.

If you go to the 2 piece shaft with the collar that adapter housing and bearings in between will also have to be found.

I donít know if those long shaft compressors are even available rebuilt.:shrug: There is timing marks on the gear you can see to get on the cam gear right for the overhead adjustment marks on the pulley.

12-23-2006, 04:12 AM
I donít know if those long shaft compressors are even available rebuilt.

They are gonna rebuild mine. I was going to do that tomorrow

12-23-2006, 04:58 AM
Good job Low!!!!!!!! I 've never seen a one piece crank to acc. drive unit. Been a bit since I learned somethin useful so this is cool for me!!! (but sorry Chris; sux for you!!) Judging from the last pic the comp is fubar'd and it's a best bet run to hit the salvage yard and grab the whole unit for $250/300 or so I'd say. Good luck Chris, and thanx agin bro...T

12-23-2006, 05:28 AM
Thanks Tony, but really Iím just telling how old I am.:damnit LOL

The first one of those compressors I pulled off was to get at the front cam follower housing. Stuff like that used to make the cam RR a full 2 day project.

Once you do one like that you never forget it..

12-23-2006, 03:38 PM
Make sure those gears are timed when you put it all back together or your Christmas won't be so merry.

12-23-2006, 06:50 PM
Lowboy wins the prize! Thanks Dude. After a sleepless night and a clear head I went to work on it this morning.

Removed the belts and the nut in front of the pully. Found a small Harbor Freight Harmonic balancer puller I bought several years ago. I was able to get the puller in between the engine and the radiator and manually pulled the pully off with an end wrench on the puller.

Slow but it worked. Compressor weighs about 70lbs:uhoh2: Lugging it out of the engine area and over the fender was quite a feat!

I made sure to mark the accessory drive cover where the keyway was pointed. So as long as the engine doesn't get turned over I can put it back in the right spot.

After I get it back I don't know how I'm going to get the big pully back on. Not much room to swing a hammer and my Harmonic Balancer installer kit doesn't have one this big.

Was thinking of freezing the shaft with refrigerant and heating the pully up and hopefully it will go on that way.

12-23-2006, 09:40 PM
Good to hear!:Thumbup:

Going on is the easy part, lube it up and I usually just pull it on with the nut after getting a few threads. Lets hope that shaft is OK for the rebuilder. They could spray the rod journal and bring it up to spec at a good crank shop. If not itís time to update the adaptor housing and the compressor..