Rebuilding Craftsman 25 gallon compressor pump

[JorWood]

My compressor seized up on me the other day and it turns out it's the pump. That thing is not turning for anybody. I've taken the pump off and removed the oil pan and I've got no idea where to go from here... my intention was to install new bearings on the crankshaft but I'm at a loss as to how to even remove the crank. I've searched online but I'm not finding anything specific to my model or to any parallel twin style compressors for that matter.

My model is a craftsman professional 25 gal 1.9 hp 150 psi model number 919.195413

Thanks guys, any help/pointers would be great. If I can't get this thing sorted I'll just bite the bullet and find a replacement pump, which I'm taking recommendations for as well lol.

Thanks,

Jordan

 

[The Cobbler]

here's a link to parts source and exploded view of the pump.I suspect that it's more than bearings. http://www.ereplacementparts.com/cr...-compressor-parts-c-158286_158287_158300.html

 

[md21722]

The oil pan is called the crankcase. Generally you have to separate the rods, remove the flywheel, and then you can get the crank out. Last one I pulled apart that wouldn't turn, it was misting oil, when freed up with a large pry bar, rings were stuck, pistons and cylinder walls were scored. What year is this? These small single stage compressors, it's often better to just go buy another one because the tank is next. Look at the the Harbor Freight $329 one. One of the only things I would buy at Harbor Freight with a power cord. Looking at the pump, it looks like its an ABAC, same folks that supply pumps this size to reputable brands like Quincy, CP, NAPA, and Rol-air. Their larger 60 gallon is definitely ABAC, another fair priced electrical item at Harbor Freight.

 

[JorWood]

Thanks for the response guys! I took the bolt off the flywheel but it does not seem to want to come off...

As far as replacement goes I was looking a the harbor freight replacement pump here http://m.harborfreight.com/145-psi-3-hp-twin-cylinder-air-compressor-pump-67697.html I'm just not sure how to check if it'll fit mine. I'd like to keep mine as it appears to only be a few years old and I just payed 325 for it a few months ago on Craigslist.

Does anyone have any experience with that pump? Campbell Huasfield has one I can get for $189... not sure of its worth the $50 extra for the brand name.

 

[JorWood]

Just noticed the intake is on the opposite side on that harbor freight pump... is that a deal breaker or do people just find a way around this? I'm fairly versed in shade tree mechanics so if there's a relatively straight forward way to do things I can usually get it done

 

[vandalthree]

That pump on your compressor is made by DeVilbiss. It's the same pump that has been on most Craftsman compressors for at least 30 years. To my knowledge they've also been used on Porter-Cable and Speedaire compressors. I have three of them in my garage - Two are at least 25 years old. One I rebuilt and is in regular service, another is a functional take-off and the third is waiting to be rebuilt. They are good pumps but if it's seized there is likely more extensive damage. Potentially bent rods, wrist pins or crank, damaged pistons etc. Any heavy scoring to the cylinder walls requires machine work to fix but oversized rings are not available and with the cost of that work it only makes sense to scrap it.

The crank is tapered at the end where the flywheel is mounted. Once the flywheel has been seated by the bolt it is "locked" in place by the taper fit. A two or three jaw puller is the best way to crack it loose. You may have to use shims behind the flywheel to give the puller a place to grab. After that take the front crankcase cover off and unbolt the rod caps and the crank is free.

If you determine a rebuild is viable please, for the love of God, don't buy those bearings from ereplacementparts for $26.93 a piece. Bearings are standard parts available off the shelf from anywhere you choose. They're even kind enough to give you the bearing part number - 6205. You can find open 6205s like the OEM ones or metal shielded ones (6205Z, 6205ZZ) or sealed ones (6205RS, 6205 2RS). I would use open or sealed but not shielded - metal shields won't keep out the oil in the crankcase. I like Nachi bearings and you should be able to find them for ~$10 a piece. I would also suggest cutting your own gaskets if you want to save money there too. The linked parts breakdown lists the ring kit as obsolete/unavailable but I may have a line on a functional equivalent should it come to that.

ETA, Bearings: https://www.amazon.com/dp/B0045DW8EO/?tag=atomicindus08-20

One consideration if buying a new pump - From the drawing and parts breakdown of your Sears pump it looks like the flywheel is driven by a poly-v flat belt, not a standard v-belt (All of mine are poly-v flat belts so I suspect yours is too). The harbor freight pump you linked is driven by a standard v-belt. If you go that route you will need an appropriately sized v-belt pulley for your motor as well.

I doubt the mounting pattern of the new pump will match your existing top plate but you would likely be able to work around the intake/discharge reversal. It just may take some thought and creativity. If you're not already you'll get very familiar with pipe, tube, fittings and valves if you spend enough time working on compressors.

 

[bsaint]

Most likely the rod is frozen to the crank. If you can find out which one, all you have to do is buy a new rod, emery cloth the journal and put it in. We used to do it ALL the time for the small units at our compressor shop when the price of the pump wasn't worth the shop labor for a full rebuild.

 

[theoldwizard1]

Thanks for the response guys! I took the bolt off the flywheel but it does not seem to want to come off...

You will likely need a puller.

 

[JorWood]

If you determine a rebuild is viable please, for the love of God, don't buy those bearings from ereplacementparts for $26.93 a piece. Bearings are standard parts available off the shelf from anywhere you choose. They're even kind enough to give you the bearing part number - 6205.

Thanks for the responses guys. Vandalthree that talk on bearings really busted me up lol. This truly is one of the best forums/communities on the web.

So I have an old pump from a very old crafstman compressor that works however the intake/exhaust is also flipped... is it easiest to try and flip the head and valves around or to try and turn the crankcase? And how do you get the head and gaskets off without ruining them? Lastly which gaskets must be replaced everytime it's opened up?

 

[vandalthree]

If the old pump is the same as your newer one, the one I know I am familiar with, I believe you would be okay flipping the head. However, you MUST also flip the valve plate. The valve plate's orientation to the head cannot be changed. You will likely damage the gaskets upon removal, no way around it, and the remnants can be a mother to scrape off. At any rate, the gaskets are the graphoil crush type and I wouldn't recommend reusing them anyway. I cut new head/valve plate gaskets from the Fel-Pro rubber fiber gasket material available at most auto parts stores. This application is nothing like an automotive head gasket and mine have been holding up now going on 8 months. I also coat them With Permatex No. 2 - the non-hardeing one. I would use the Permatex on all paper/fiber gaskets in the pump. I wouldn't use it on new OEM graphoil gaskets.

Personally, I think the Fel-Pro material is better than whatever the OEM gaskets are made of. All three of these pumps I've taken apart had gaskets that had been fully permeated by oil. Strictly speaking, though, you could get away with reusing the gaskets for the bottom and front of the crankcase as long as they aren't damaged. If you want to stick with OEM for the head gaskets I would get new ones. If I recall correctly, the torque spec for the head is 25 ft-lbs.

I should also mention that the thickness of the front crankcase cover gasket is somewhat important - It sets the end play of the crank to prevent thrust movement. Too thick of a gasket and there will be noticeable thrust motion in the crank. This may not actually be a big deal since thrust loading isn't imparted to the crank like it is in combustion engines with helical gears - Just something to think about. So, if you can get that gasket off intact, I would intentionally reuse it, you'll notice how much thinner it is than the others. Degrease it and use the permatex sealer on it.

 

[JorWood]

Thanks for the response! Turns out the bolt pattern doesn't line up... now to decide if I want to break the drill out...

 

[md21722]

Thanks for the response! Turns out the bolt pattern doesn't line up... now to decide if I want to break the drill out...

It is a non-issue to replace the pump. I set it place so the belt(s) aligns with motor sheave & then use transfer punches to mark pump holes. From there I center punch, drill & install the new pump.

 

[md21722]

Simply saw the admission is on the inverse side on that harbor cargo pump... is that a major issue or do individuals simply discover a route around this? I'm genuinely versed in shade tree mechanics so if there's a moderately straight forward approach to do things I can normally complete it

Typically the cleanest adaptation is to bend a new copper tube that goes across the the front of the pump into the tank. Pipe can also be used but you don't typically see that on a compressor this size.

 

[redmondjp]

Typically the cleanest adaptation is to bend a new copper tube that goes across the the front of the pump into the tank. Pipe can also be used but you don't typically see that on a compressor this size.

That's exactly what I was going to suggest. Copper pipe is an excellent conductor of heat, so the longer this pipe is, the more of an aftercooler you are creating which helps to cool down the air before it enters the tank. If you are a bit crafty, you can even bend some coils into it.

 

[JorWood]

Most likely the rod is frozen to the crank. If you can find out which one, all you have to do is buy a new rod, emery cloth the journal and put it in. We used to do it ALL the time for the small units at our compressor shop when the price of the pump wasn't worth the shop labor for a full rebuild.

This was correct. Just one rod is frozen. I'm having trouble finding a replacement rod... is there a way to reuse the old one?

 

[JorWood]

I finally got around to taking emory cloth to the crankshaft and removed all the aluminum from the rods that was worked in there. I also lightly sanded the connecting rods and it's purring like new again. However in my ignorance I took the head off to poke around and now I need a new head gasket if I want more than 40psi in my tank...

Thanks again for the help guys!

Jordan

 

[JorWood]

$7 to ship a $7 head gasket... as a man of principle I might be making a homemade head gasket.