Type of lubrication an "oil free" air compressor uses?

[fleabag]

I have a "husky" air compressor that I'm attempting to rebuild as I found the internals to be very dirty. I mostly started working on this because it wouldn't run anymore and found the culprit to be a faulty switch. But before I found the switch to be at fault, I took apart the compressor assembly and found a lot of dirt due to there not being a filter on the intake. So anyway I have the piston out and I cleaned up the piston, the ring and the cylinder with rubbing alcohol, removed some particulate matter and I'm done. So now I'm wondering, what kind of oil should I put in here to lubricate it?

This is technically a maintenance free air compressor, so I don't exactly know what the difference between an "oil" and "oil free" air compressor is except that the prior you don't have to add oil. Do they for the most part use the same oil? Can I just use 5w-30 motor oil in place of the compressor oil?

Update: I've fully reassembled the air compressor and I tested it up to 5 psi, seemed to run smoothly. However I don't have any air tools so I didn't feel comfortable in bringing the compressor to 100psi and or doing continuous testing so I don't know at this time whether or not it will hold up.


Now that I've tackled that project, onto the next one. I have a Diehard battery booster, portable power and compressor. http://www.sears.com/shc/s/p_10153_1...&blockType=G15

Well one day when I was inflating the tires of my truck, I hooked it up and left it alone for several hours (forgot about it) and the compressor stopped working. Everything else worked on it except the compressor and so, after further visual inspection and finding some oil on the bottom of the unit, I concluded that the compressor had seized. Since I really only needed the compressor that comes with this unit, it has been useless to me since it stopped working in 2008. So flash forward to today when I "completed" (we'll see!) work on a broken air compressor, I felt like I had the ability to tackle this looming project of mine. Alright, so I took the unit apart, took out the compressor assembly and I was able to confirm my suspicions, the compressor was completely seized. So I took the compressor apart and I found a bunch of metal shavings on top of the piston and inside of the cylinder.

Alright, so this is the real crux of the problem, something that might affect BOTH compressors. The Designs of BOTH air compressors are almost identical, the difference on this second air compressor that I've found is that it's covered in oil on the outside (leaked). I think the reason why my compressor failed is because it got too hot and all the oil left the compressor, causing it to seize. I didn't find evidence of any oil actually on the first compressor but this second one looks like it has oil like I would expect it to. Keep in mind that the first compressor wasn't having any problems, it was just that since I was already in there, I figured I'd clean things up and attempt to bring it to "like new" condition.

So now I'm wondering, how should I lubricate this compressor and what should I do? Maybe this is an older design that uses oil and has no teflon coating on the cylinder walls, therefore that's the reason why it failed? That maybe I could clean things up and try applying that same teflon stuff myself? I'm not really sure what to do now.

 

[Ksyder]

http://www.carsdirect.com/car-repair/buyers-guide-oil-free-or-oil-air-compressor

Air compressors draw air in with a piston. The air is then compressed into a storage tank. For maximum efficiency, the piston chamber needs adequate lubrication, for which oil is used. These are oil air compressors. However, in oil-free compressors, the cylinder is pre-lubricated (mostly with Teflon) for permanent lubrication. The Teflon coating protects the pump. That’s the major difference. While oil compressors need regular oiling, the latter doesn’t require any lubrication.

I don't know for sure, but figured I'd tried to help.

 

[grrl]

<snip>before I found the switch to be at fault, I took apart the compressor assembly<snip>

That's an impressive diagnostic routine.

 

[Taejin]

just thought, in case a mod sees this, foot003 is just a spammer

 

[alfa147x]

just thought, in case a mod sees this, foot003 is just a spammer

just FYI you can hit the

to report posts

 

[Taejin]

just FYI you can hit the

to report posts

orly

 

[RedArmy]

Wow, talk about deja vu. Someone asked me pretty much this exact same question at work on Monday.

 

[fleabag]

Wow, talk about deja vu. Someone asked me pretty much this exact same question at work on Monday.

and the answer was?

 

[l0cke]

Wow, talk about deja vu. Someone asked me pretty much this exact same question at work on Monday.

That person is Fleabag. You know what must be done. :hmm:

 

[Wolfsraider]

dude save yourself the headache...buy compressor oil made for piston type compressors and do it right

royaL purple makes some and even walmart carries a few versions

 

[fleabag]

I decided to use some white lithium grease and we'll see if it works out or not..

 

[fleabag]

dude save yourself the headache...buy compressor oil made for piston type compressors and do it right

royaL purple makes some and even walmart carries a few versions

the oil wouldn't make sense considering that it's an oil free compressor. Oil free compressors don't have pumps to push oil through all the crevices like oil compressors do. That's why I asked since this clearly isn't an oil compressor. I read some places that oil free compressors use like teflon to lubricate the parts but I don't have any so I'm going with the white lithium grease for now. Maybe I'll buy this http://www.properautocare.com/dupelu.html if it doesn't work out.

 

[fleabag]

dude save yourself the headache...buy compressor oil made for piston type compressors and do it right

royaL purple makes some and even walmart carries a few versions

As for the switch, I'm not going to replace it as I managed to take the switch apart by lightly prying out the plastic rocker. Then I inspected the switch and found a lot of saw dust and other dirt, so I clean up all the contacts, sanded them down a bit and reassembled it. This should pretty much be the difference between 0 continuity and full continuity.

 

[dud]

Maintenance-free compressors do not use oil, they utilize a teflon sleeve or coating on the cylinder wall. They are not meant to last as long as oil-lubricated types. You may have to consider disposing of the unit if the legacy lubricant (teflon or whatever the manufacturer used) is gone.

 

[LTC8K6]

Most air compressors don't have an oil pump at all. They use oil slingers and rely on splash oiling.

 

[Rubycon]

Most air compressors don't have an oil pump at all. They use oil slingers and rely on splash oiling.

Well sure but they still need a crankcase for this.

Oil less compressors are maintenance free as far as lubrication is concerned. You NEVER need to apply anything - as others have said they are permanently lubricated for life. If the intake filters are maintained (and most importantly left in place!) the pump should have an acceptable life span. Once you lose compression it's time to replace the pump. The oil less design is VERY loud in comparison to a slower speed lubricated pump. Many manufacturer's greatly exaggerate the power claims with these products as well. (in the home market)

A better compressor will have a crankcase at the bottom and is typically filled with common SAE "ash free" 30 weight oil or synthetic oil per manufacturer's recommendation. Better compressors (typically 5-30+ hp range multiple stage) most definitely use a positive displacement oil pump for pressurized lubrication - not much different than your car's engine. The Quincy QR-25 is one such model and these things are designed for 24/7 duty to 250 psig and 500 psig intermittently. If there was a "tank style" of compressor pump, it would be this one. :awe:

 

[fleabag]

How come the air compressors aren't made with stainless steel and or painted on the inside so that they don't rust? I'm really tempted to add something inside of the tank in order to make it not rust.

 

[Rubycon]

Stainless steel can still succumb to corrosion unless SPECIFICALLY fitted for the application and proper use of fittings and welding (along with proper SS type!) is completely followed through. Read that as VERY expensive.

A steel vessel could be epoxy coated on the inside for better corrosion resistance.

Of course proper condensation drain schedule as everyone follows in the industry for the past 75+ years affords long vessel life and safe operation. Most industrial environments with multiple machines/receivers use an automatic drain cock which is a solenoid actuated valve activated by a timer or hygrometric controller (more frequent ventings in humid conditions, etc.) On large receivers these are always fun to walk by when they open - 1" diameter vent with 180 psig behind it is ridiculously loud like 155 dB at 10 feet!

 

[drnickriviera]

Well sure but they still need a crankcase for this.

Oil less compressors are maintenance free as far as lubrication is concerned. You NEVER need to apply anything - as others have said they are permanently lubricated for life. If the intake filters are maintained (and most importantly left in place!) the pump should have an acceptable life span. Once you lose compression it's time to replace the pump. The oil less design is VERY loud in comparison to a slower speed lubricated pump. Many manufacturer's greatly exaggerate the power claims with these products as well. (in the home market)

A better compressor will have a crankcase at the bottom and is typically filled with common SAE "ash free" 30 weight oil or synthetic oil per manufacturer's recommendation. Better compressors (typically 5-30+ hp range multiple stage) most definitely use a positive displacement oil pump for pressurized lubrication - not much different than your car's engine. The Quincy QR-25 is one such model and these things are designed for 24/7 duty to 250 psig and 500 psig intermittently. If there was a "tank style" of compressor pump, it would be this one. :awe:

Yeah, permanently lubed, that's like the lifetime transmission fluid they've been using in cars. It will last a lifetime. Until it blows itself to pieces. I have an oil less one, never again. I've already had to rebuild it twice.

Wasn't there a class action lawsuit against the compressor mfgs about the inflated HP claims? I think they are supposed to be listing more realistic numbers now.

 

[PlasmaBomb]

That person is Fleabag. You know what must be done. :hmm:

lol

 

[Eli]

You added lithium grease to an oil-less compressor?

LOL

As others have said, no lubrication is required. Sounds like you need to take it back apart to clean it again.

Also, I don't think you know what teflon is. Hint: It is a solid. It's not something you add to a maintenance free compressor, the parts come from the factory pre-coated. If the teflon has worn off, the unit has reached the end of its life cycle and needs to be rebuilt.

 

[Kirby]

Stainless steel can still succumb to corrosion unless SPECIFICALLY fitted for the application and proper use of fittings and welding (along with proper SS type!) is completely followed through. Read that as VERY expensive.

A steel vessel could be epoxy coated on the inside for better corrosion resistance.

Of course proper condensation drain schedule as everyone follows in the industry for the past 75+ years affords long vessel life and safe operation. Most industrial environments with multiple machines/receivers use an automatic drain cock which is a solenoid actuated valve activated by a timer or hygrometric controller (more frequent ventings in humid conditions, etc.) On large receivers these are always fun to walk by when they open - 1" diameter vent with 180 psig behind it is ridiculously loud like 155 dB at 10 feet!

automatic drain cock? :fap:

 

[LTC8K6]

Well sure but they still need a crankcase for this.

Oil less compressors are maintenance free as far as lubrication is concerned. You NEVER need to apply anything - as others have said they are permanently lubricated for life. If the intake filters are maintained (and most importantly left in place!) the pump should have an acceptable life span. Once you lose compression it's time to replace the pump. The oil less design is VERY loud in comparison to a slower speed lubricated pump. Many manufacturer's greatly exaggerate the power claims with these products as well. (in the home market)

A better compressor will have a crankcase at the bottom and is typically filled with common SAE "ash free" 30 weight oil or synthetic oil per manufacturer's recommendation. Better compressors (typically 5-30+ hp range multiple stage) most definitely use a positive displacement oil pump for pressurized lubrication - not much different than your car's engine. The Quincy QR-25 is one such model and these things are designed for 24/7 duty to 250 psig and 500 psig intermittently. If there was a "tank style" of compressor pump, it would be this one. :awe:

The key to a long life for an oil-free compressor is to do the break in like you are supposed to. Generally this is to run it for a while with the drain valve open so no pressure builds up in the tank. That is, to run it without a load for a while.

Most people are unlikely to have any experience at their homes with high-end compressors that would have oil pumps, so I left them out. The compressors that people generally have in their homes and garages wouldn't have oil pumps.

For sling or splash oiling, you want to be sure the oil won't foam.

 

[fleabag]

Alright, so despite that there were metal shavings in the cylinder, it turns out that the real problem is with the compressor electric motor itself which is completely seized. I looked inside the motor and everything is melted. I found the manufacturer of the motor http://cfmotor.en.alibaba.com/product/314869269-209563363/dc_motor_small_motor_RS_540A_RS_545A_.html but the problem is I have no idea how fast the motor spins so finding a replacement is going to be difficult for me unless the manufacturer will tell me the exact specs of the motor.

 

[Demon-Xanth]

Just save yourself time and money and buy an 800PSI compressor so you can inflate tires to what they can actually take. This should get you 75MPG and you can go to the gym.

That compressor sounds like it's not worth rebuilding at this point. Too much monkeying around with it.