Tools, Sharpening and Power Machinery - Craftsman compressor will not go over 40
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vtxrider
10-17-09, 09:20 PM
I have a Craftsman 6hp 30 gal. It will not go over 40lbs of pressure. Once it gets to 40, it stays running. I have the regulator set to the highest. It's about 4 years old and used lightly. I have no leaks. It ran fine building pressure to 120 the last time I used it. I made the mistake of letting someone use it and now this. (sorry, last sentence was venting)
Any clues?
Any clues?
chandler
10-18-09, 04:58 AM
Welcome to the forums! You say you have no leaks. I am sure you have used soapy water to determine this. If so, then you most likely have a reed valve problem in the head of the compressor, or bad rings on the compressor piston. I am not sure if your compressor is oil or oilless, so I am covering it generically. You may can clarify the type.
marksr
10-18-09, 05:31 AM
I have a portable compressor that had the same symptons years ago. I tore the pump down expecting the worst when it turned out the only problem was where the compressor had got bumped around in the van, the adjustment for the drive belt got loosened. It would build up so much pressure and then the belt would start to slip - check the easy stuff first :D
vtxrider
10-18-09, 08:32 AM
Welcome to the forums! You say you have no leaks. I am sure you have used soapy water to determine this. If so, then you most likely have a reed valve problem in the head of the compressor, or bad rings on the compressor piston. I am not sure if your compressor is oil or oilless, so I am covering it generically. You may can clarify the type.
I went over the thing and there are no leaks. I use to install peneumatic controlled machines for a drycleaning company. That was my first check. The compressor is a upright oil-less 6hp 30 gal. it's about 3 yrs old. For it's use I doubt it's the rings. I'm not sure about reeds as I'm unfamilar with that.
One thing that's suspect that's the last time I used it, it ran fine pumping up to 150. When my neighbor borrowed it we lifted up into his SUV and laid it down. From there I'm not sure how it was handled. No signs of being dropped (first thing checked) or mishandled. He was using it to winterize his sprinklers. He said he put it on and it ran up to 40lbs and stayed. It never shut off. When he returned it I put it on and the same. I have it set for 150 and that was not changed. I'm kind of ruling out the regulator for now.
I'm not sure of the workings of this head, reed valves, whether it's beltless or not. Would something have been knocked out of whack during the transportation of it? I'm going to check what the other response was of a belt loose.
Thanks for any help on this.
I went over the thing and there are no leaks. I use to install peneumatic controlled machines for a drycleaning company. That was my first check. The compressor is a upright oil-less 6hp 30 gal. it's about 3 yrs old. For it's use I doubt it's the rings. I'm not sure about reeds as I'm unfamilar with that.
One thing that's suspect that's the last time I used it, it ran fine pumping up to 150. When my neighbor borrowed it we lifted up into his SUV and laid it down. From there I'm not sure how it was handled. No signs of being dropped (first thing checked) or mishandled. He was using it to winterize his sprinklers. He said he put it on and it ran up to 40lbs and stayed. It never shut off. When he returned it I put it on and the same. I have it set for 150 and that was not changed. I'm kind of ruling out the regulator for now.
I'm not sure of the workings of this head, reed valves, whether it's beltless or not. Would something have been knocked out of whack during the transportation of it? I'm going to check what the other response was of a belt loose.
Thanks for any help on this.
vtxrider
10-18-09, 11:38 AM
Well I took the cover off. BTW my model # is 919167312. No signs of leaking from the lines. I took off the check valve and inspected that. I took off the line going from the head to the tank. I ran the motor and it's moves air but I'm not sure if it's moving enough. If I had another unit to compare, that would be nice. I turned the motor by hand and it pumps air but it seems to turn easy. Maybe I'm expecting too much compression. Would it be something electrical other then pneumatic?
Not alot going on "under the hood" with these things. Hopefully something simple. On to looking at the reed valves...like I know what I'm looking at :)
Not alot going on "under the hood" with these things. Hopefully something simple. On to looking at the reed valves...like I know what I'm looking at :)
GregH
10-18-09, 03:10 PM
If you go to the Sears website and look under Parts Direct you can enter your model number and find the parts list.
It looks like your unit has a diaphram for pumping and a valve plate.
It could be either or both of these parts that are your problem.
It looks like your unit has a diaphram for pumping and a valve plate.
It could be either or both of these parts that are your problem.
vtxrider
10-18-09, 06:21 PM
If you go to the Sears website and look under Parts Direct you can enter your model number and find the parts list.
It looks like your unit has a diaphram for pumping and a valve plate.
It could be either or both of these parts that are your problem.
I took off the head and lifted up the valve plate. Not really knowing what I was actually looking at, I flipped it around and had a little metal piece fall out and hit the floor. After a few minutes of crawling around I found it. I looked at the plate and saw it had 3 little paddle looking things with one that was broken off. I took off that thing that holds it on and lifted it out. It looked like the piece that fell out. I'm guessing that's my problem or part of it. I ordered a new plate and new O rings. I inspected the cylinder and piston and it looks ok. The site said the plate is a Mfg authorized substituted part. Which means it might fit.:eek: We'll see in a few days.
It looks like your unit has a diaphram for pumping and a valve plate.
It could be either or both of these parts that are your problem.
I took off the head and lifted up the valve plate. Not really knowing what I was actually looking at, I flipped it around and had a little metal piece fall out and hit the floor. After a few minutes of crawling around I found it. I looked at the plate and saw it had 3 little paddle looking things with one that was broken off. I took off that thing that holds it on and lifted it out. It looked like the piece that fell out. I'm guessing that's my problem or part of it. I ordered a new plate and new O rings. I inspected the cylinder and piston and it looks ok. The site said the plate is a Mfg authorized substituted part. Which means it might fit.:eek: We'll see in a few days.
chandler
10-19-09, 06:59 AM
That is (or was) your reed valve. Generally that is what breaks. Glad you were gutsy enough to take it down and find the problem. Let us know if the replacement works or not.
Larry
Larry
vtxrider
10-24-09, 10:57 AM
That is (or was) your reed valve. Generally that is what breaks. Glad you were gutsy enough to take it down and find the problem. Let us know if the replacement works or not.
Larry
Nothing gutsy about this thing, there's nothing to it parts wise. I put the new plate in and torqued it down. Runs like new.
thanks for the replies
Larry
Nothing gutsy about this thing, there's nothing to it parts wise. I put the new plate in and torqued it down. Runs like new.
thanks for the replies
Claw Hammer
10-24-09, 09:45 PM
Usually the con rod or the piston breaks and we just throw away the compressor and keep the tank.
You can buy a real compressor from Harbor Freight for about $99 and a new motor for about another $99 and have a real shop compressor that doesn't rattle and shake and make more noise then a 747 on take off.
The plus side is - a real compressor can be put in a compressor room with little heat and still work. The oiless compressors do not like the cold and will not run when it gets too cold in the compressor room.
You can buy a real compressor from Harbor Freight for about $99 and a new motor for about another $99 and have a real shop compressor that doesn't rattle and shake and make more noise then a 747 on take off.
The plus side is - a real compressor can be put in a compressor room with little heat and still work. The oiless compressors do not like the cold and will not run when it gets too cold in the compressor room.
vtxrider
10-25-09, 08:02 PM
Usually the con rod or the piston breaks and we just throw away the compressor and keep the tank. You can buy a real compressor from Harbor Freight for about $99 and a new motor for about another $99 and have a real shop compressor that doesn't rattle and shake and make more noise then a 747 on take off. The plus side is - a real compressor can be put in a compressor room with little heat and still work. The oiless compressors do not like the cold and will not run when it gets too cold in the compressor room. I have no complaints about this compressor. Maybe it could be quieter but so could my VTX 1800 with the Roadhouse exhaust. Ether doesn't bother me. Maybe my neighbors but not me. I have a 30x40 garage which is part of the house. Here in New England dips to 40 inside during the winter. The compressor runs fine in that temp. I don't run any business it just has my "toys" in it. It does its job when needed. Other then the motor, the rebuild of it is cheap and easy. My previous job as I stated before took me in to compressor rooms which held real units that ran entire plants not shops. The old V Twins IR's sounded like the 747's as you mentioned or gatling guns. Even the new units are loud. All in all until the motor craps out, I'll keep it. Besides it cost me nothing....it was a gift.