Air compressor pump rebuild?

[woodman2011]

I bought a 1968 quincy 230-33 air compressor it built pressure at the guys house but I was in a hurry and didn't check how high screwed up there. So I get it home only built up to 20 psi.
Next day tried it again and it built to 100 psi where the shutoff is. Drained it till the motor kicked on 3 times it seemed slow but went up to a 100 every time.
I then drained it all the way so I could time it from 0 to 100 and again it wouldn't build pass 20 psi
Does this sound like it needs a pump rebuild?
Anyone familiar with rebuilding it that could help me along the way?

 

[TonyJ]

100 is the max pressure that the 230 is supposed to do. By what your saying it sounds like to me that you have a valve that isn’t sealing or that it’s running in unloaded mode. Disconnect the copper line going to the top of the pump and that will keep the pump from unloading. While running it again hold your thumb in the copper line to keep it plugged so air can’t pass and see if it will go above 20. Also what is the oil pressure while it’s running ? Low oil pressure will make the unloaders stay unloaded.


Tony

 

[woodman2011]

I'll try that once I get home. It doesn't have a gauge for oil pressure unfortunately. Any other way to check?

 

[TonyJ]

The problem that I think your going to have is that the unloaders or unloader is sticking but if so don’t worry cause that would be a easy fix


Tony

 

[TonyJ]

I'll try that once I get home. It doesn't have a gauge for oil pressure unfortunately. Any other way to check?

The way the oil pressure unloader works is there is a line that has tank air pressure on it at all times and it’s connected to the bottom side of the hydraulic valve that’s located on the crankcase on the right side when viewed from the back. On the top of that same valve is a copper line that runs to the top of the pump and connects to the unloaders and that’s the spot you need to disconnect it from when trying what I said earlier. A way to see if it has enough oil pressure can be found out when you have that line unhooked. When you have it unhooked and start the compressor air should start blowing out of the line for a few seconds and if the air stops blowing then the oil pressure is high enough to close the hydraulic valve. If it does that then we will move to the next step and that’s to see if the unloaders are sticking or if you have valves that needed removed and cleaned and checked. Mine is a 230-28 from 1963 and I also have all of the manuals for the 230


Tony

 

[The Tool Tyrant]

Woodman, If it is equipped with an hydraulic unloader ( it is threaded into the top of the bearing carrier and has a 1/4" copper supply to going to the receiver and the other side to the unloader towers) it is possible it's bad/ sticking.

Tony beat me to it!

 

[TonyJ]

Woodman, If it is equipped with an hydraulic unloader ( it is threaded into the top of the bearing carrier and has a 1/4" copper supply to going to the receiver and the other side to the unloader towers) it is possible it's bad/ sticking.

Tony beat me to it!

My guess is it’s going to be the brass pistons in one of the unloaders that is sticking because it picks and chooses when it wants to build up air lol. But making sure the hydraulic valve is working first and has enough oil pressure sends us to the next spot of a potential problem


Tony

 

[The Tool Tyrant]

My guess is it’s going to be the brass pistons in one of the unloaders that is sticking because it picks and chooses when it wants to build up air lol. But making sure the hydraulic valve is working first and has enough oil pressure sends us to the next spot of a potential problem


Tony

First item to check would be oil...has it been changed in the last 30 years???
Some folks don't follow good maintenance schedules. Could just be old funky oil has gummed up the hydraulic unloader.

 

[woodman2011]

Okay, I took off the top line it built pressure to about 25 with my finger over the line I didn't feel any air.
When I turned the compressor off then air came out of the line.

 

[TonyJ]

Your pictures aren’t displaying. Send them to me in a pm and I’ll post them for you and see if that’ll work


Tony

 

[TonyJ]

No air out of line while running and air coming out when it’s turned off is a good sign the hydraulic valve is working.


Tony

 

[TonyJ]

Next step would be the unloaders on the top. Don’t worry about the 6 bolts that holds the very top plate on for now. Your going to need a pipe wrench that is big enough to fit the outside of the top of the unloaders and take those off. Be careful because they can break if they are really really stuck on there.


Tony

 

[woodman2011]

Okay unloaders came off pretty easily what exactly am I looking for? There is a bit of rust in the top part. On the botto. Part one is clean and the other is oily.

 

[TonyJ]

Okay unloaders came off pretty easily what exactly am I looking for? There is a bit of rust in the top part. On the botto. Part one is clean and the other is oily.

There is a brass piston looking thing make sure it moves freely.


Tony

 

[TonyJ]

Lift those parts out and under it is a flat washer and under that is a valve with pins in it and a spring on each spring. Remove those and make sure their clean and free


Tony

 

[woodman2011]

There is a brass piston looking thing make sure it moves freely.


Tony

I would say they moved freely both fell out as soon as I moved the top

 

[TonyJ]

I would say they moved freely both fell out as soon as I moved the top

Ok lift the valves out and check them. The 3 pins when the unloaders are working push’s the check valve disk down and holds them open during start up and during low oil pressure so it runs unloaded. So make sure all is clean and free


Tony

 

[TonyJ]

Also I send you the manuals to your email. You can look thru those for more info


Tony

 

[The Tool Tyrant]

Woodman, if you want to look at the Quincy parts manual, go to Quincycompressor.com,
Under 'PRODUCTS' click on 'QR-25', on the right side of the QR-25 page under 'QUICK LINKS', click 'DOWNLOAD LITERATURE'. Under the picture of the monitor you'll read 'Browse, view,...click on the round 'GO' symbol, on the next page in the 'SEARCH' window
search 'ANY TYPE' , in the 'KEY WORDS' window type QR 230. Scroll down on the right hand column to the one dated 1/1/1969 and download. That contains info for ROC 32.
The manual on the left side dated 11/1/1986 is an addendum which includes changes to ROC 33.
I wish I could find an easier way to get from 'point A' to 'point B', but I haven't found it yet!
The parts manual will probably help when Tony is describing parts.

AGAIN! Tony beats me to it!

 

[woodman2011]

So the side that was oily had the 3 pins with there springs which were all good but there pushing down on 1 bigger spring correct? That one is broken. It also doesn't have a crush washer like the other side.
So I need 1 new valve and a crushed washer?

 

[TonyJ]

So the side that was oily had the 3 pins with there springs which were all good but there pushing down on 1 bigger spring correct? That one is broken. It also doesn't have a crush washer like the other side.

So I need 1 new valve and a crushed washer?

The crush washer yes you need. The pins are pushing down on the check valve disk and the spring under that disk you said is broken needs to be replaced too. So your down to needing a spring and 2 crush washers. Any time those valves are removed they should be replaced. You can if you want to go ahead and check the exhaust valves. But it sounds like you done found your problems. The manuals I sent to you you can find the part numbers for each part and not have to buy the whole valve.


Tony

 

[TonyJ]

Woodman, if you want to look at the Quincy parts manual, go to Quincycompressor.com,
Under 'PRODUCTS' click on 'QR-25', on the right side of the QR-25 page under 'QUICK LINKS', click 'DOWNLOAD LITERATURE'. Under the picture of the monitor you'll read 'Browse, view,...click on the round 'GO' symbol, on the next page in the 'SEARCH' window
search 'ANY TYPE' , in the 'KEY WORDS' window type QR 230. Scroll down on the right hand column to the one dated 1/1/1969 and download. That contains info for ROC 32.
The manual on the left side dated 11/1/1986 is an addendum which includes changes to ROC 33.
I wish I could find an easier way to get from 'point A' to 'point B', but I haven't found it yet!
The parts manual will probably help when Tony is describing parts.

AGAIN! Tony beats me to it!

Haha I’m just trying to do my part here on the GJ lol. I have a 230 roc 28 and have done been thru all this that the OP is going thru except mine wouldn’t go to 100 at all at first


Tony

 

[sberry]

Good trouble shooting in this thread. Find the problems rush to rebuild.

 

[woodman2011]

So is there any reason to go farther into the pump or get the new spring change the oil and call it good?

Again thanks for the help I was devastated I bought this compressor and didn't check it out well enough. I then called a Quincy dealer and he said usually it's cheaper to replace the pump and when I check how much the pump was on Ebay I about gave up all hope. Lol

 

[TonyJ]

So is there any reason to go farther into the pump or get the new spring change the oil and call it good?

Again thanks for the help I was devastated I bought this compressor and didn't check it out well enough. I then called a Quincy dealer and he said usually it's cheaper to replace the pump and when I check how much the pump was on Ebay I about gave up all hope. Lol

I would say there is no reason to dig any deeper. With that valve spring being broken that is allowing the air to just move back and forth from the cylinder to the air filter. We know it sometimes builds to 100 like it’s supposed to so a oil change and the parts you should be good to go. Check the manuals for the part numbers for those parts and look online for the parts. eBay usually has the complete valves but usually doesn’t have the separate parts. I think I only gave like $30 for all 4 springs and all 4 check valve disks when I got mine. So these parts you need won’t be bad at all and that pump is totally worth the few bucks. Also Quincy themselves told me you can safely run it at 125psi max ant that’s what I run mine at on a 80gal tank


Tony

 

[The Tool Tyrant]

Great work Tony! Your past experience with the older 230 really helped cut to the chase.

One more thing Woodman...when you change your oil, the larger hex head 'bolt' to the right of the drain plug is the oil screen. Be sure to remove and clean it before replacing the oil.

 

[TonyJ]

Great work Tony! Your past experience with the older 230 really helped cut to the chase.

One more thing Woodman...when you change your oil, the larger hex head 'bolt' to the right of the drain plug is the oil screen. Be sure to remove and clean it before replacing the oil.

Thanks and I don’t mind at all helping others. Only way to learn is to get your hands dirty and learn as you go. The qr25’s are very easy to figure out when they have problems and parts are very easy to get and reasonably priced


Tony