Fixing an air compressor! Is it worth it!

[Ben Dono]

Just a quick question.

I have a cheap air compressor about 5yrs old $200 ish bunnies job
Lately it was taking a long time to reach the cut off psi and now it won't make it past 100psi. It will dump almost all of the pressure in 24hrs and I can't hear a leak anywhere so I'm guessing it's deep in the pump?

Anyone have any experience stripping one apart? I'm guessing it's the same setup at a high pressure water blaster maybe..I fixed one last summer and they have a whole lot of seals but I was lucky as I had a replacement set from the factory.

Anyone fixed a similar problem with an air compressor?

[jatt]

I would toss it myself. If it was a half decent unit like the Peerless, then different story.

Broke my sml cheapy not too long ago. It fell over in the back of the ute and busted the reg off at the fitting. Oh well just went and picked up another elcheapo for site work. Worst bit was my old one was better wrt running stuff like the nail gun. Its seems not all elcheapos are created equal!!

[KBs PensNmore]

I got an elcheapo also, takes 20 mins to get to 100 psi, touch spray gun 1 Min wait 20 mins etc...
Anybody want it.
Kryn

[nearnexus]

Those cheap direct drive compressors are notorious for leaky head gasket - hence slow/no pressure.

Pull off the head and add some silicone sealant to the gasket and see how it goes.

10 minute job.

Rob

[azzrock]

hay if your going to ditch it any way you may as well have a look.
could be something that can be repaired.
id pull the head of and have look
aaron

[LordBug]

If it's a direct drive, I'd use that as an excuse to save up for an upgrade.
If it was actually a really decent machine, then I'd probably give it a go.

[Skew ChiDAMN!!]

Worth it? Probably not.

I'd still strip it down, purely out of curiosity.. it's not like it's particularly useful as it is. And you may be pleasantly surprised.


I'd also run a few tests before proceeding, as it may not be what you suspect. Not all leaks are audible and it's possible it is just a leaking external connection. Pay particular attention to the drain port or any external fittings that protrude enough to be subject to knocking about.

Good luck with it!

[th62]

I bought an Ingersol Rand direct drive compressor back around 95 I believe. The el cheapo GMC and the like weren't available then. Perhaps the el cheapos copied the Ingersol Rand, you'd be hard pressed to tell the difference, they look identical. Matter of fact, I replaced the plastic cover with a cover from one of the el cheapos I found at the local tip - it fitted perfectly. The Ingersol Rand was by no means cheap at the time - over $600. Parts for the el cheapos are plentiful at local tips and super cheap. I forgot to mention, not long after I bought it the dipstick started popping out. I replaced the O ring on the dipstick and never had any further problems. Obviously air bypasses the piston and pressurises the crankcase, so the leak may come from the the crankcase sidecover.

[malb]

There should be a one way valve at the point where the comp outlet connects to the tank. There is normally a finer tube running from that valve to the pressure activated switch. Once the tank gets to switch off pressure and activates the switch contacts to stop the motor, it also bleeds all air out of the compressor to tank plumbing so when the motor starts, it has a chance to wind up before facing tank pressure. The one way valve should prevent bleed back and and pressure loss via the pump.

With regard to leakdown overnight, it is possible for there to be a leak at the water trap, outlet fitting, tank drain point, regulator or pressure switch mounting points. My 3HP 2cyl unit will leak down through the outlet Nitto (genuine) fitting in a couple of hours without making a sound if the outlet valve immediately before it is left open, but will hold pressure for at least a month if the outlet valve is closed. However the tank should be bleed down and drained regularly (daily for regular use) to clear condensation from the tank.

Check the inlet air filter for dirt, and all plumbing connections for leaks with soapy water (look for bubbles) to try and track down the slow pumping issue. I know of a few comps that have had a short run in dusty conditions without the inlet filter and suffered permanent damage to cylinder bore and piston allowing internal leakdown and substantially poorer pumping.

[cba_melbourne]

.....................
Lately it was taking a long time to reach the cut off psi and now it won't make it past 100psi. It will dump almost all of the pressure in 24hrs and I can't hear a leak anywhere so I'm guessing it's deep in the pump?
.....................

Is it worth your time? To be honest, no. But....


There is a one way valve between the compressor and the storage tank. It usually sits inside the angled fitting where the pipe from the cylinder head enters the storage vessel. I would start checking that, give it a clean. If that one way valve does its job, no air can leak back from it into the compresor. Buy a beer bottle and drink its content. Now fill the empty beer bottle with water and add a spoonful dish washing detergent into it and shake. Pour this over every fitting attached to the pressure vessel whilst under pressure - the pressure regulator, the one way valve, the drain, the air outlet including any regulator attached. If you see bubbles you have found a leak. You can also buy the soapy water in a fancy plastic bottle with pull out tube to apply, it is called "Snoop" and made by SwageLock and costs much more than the beer ... That should fix your pressure dumping problem overnight. If you found a bad one way valve or a major leak, this may also improve the "not reaching 100psi" problem, possibly to the point to last a few more months. This may give you some time to look for a new unit.

I assume you do top up the oil in the compressor and change occasionally? And drain the water in the receiver tank regularly?

If looking for a new smallish unit, I think:

- for occasional home use a Chinese unit can last for 5-10 years or several hundred to maybe a few thousand running hours. Better models come with 3 year warranty. If that is all you need, spending more money would be a waste.

- good brand name units have better quality motors, and usually an Italian made compressor, and better pressure switch, and "real" pipe fittings. Made to run continuously for long times, and to last for more than 10,000 hours. And can be rebuilt. Well worth the 2-3x higher price tag if you need it to earn a living. Note that 10,000 hours is about the equivalent of 13 Months of nonstop running day and night 7 days a week.

- good brand name units sold second hand are usually either totally worn out, or grossly overpriced. 10+ year old units seem to sell for what the better Chinese models sell mew. IMO not a bargain, if it turns out you have to spend extra time and money to fix it before you can use it.

[BobL]

Your problem sounds exactly like what happened to my compressor.

I have an el-cheapo also from Bunnings for $149 about 6 years ago. I was hoping it would die so I could upgrade it but nothing I could seem to do to it would kill it.

The motor stopped working and when I pulled the cover off and the motor fan had come loose and fallen off causing the thermal overload switch on the motor to turn the motor off.
Put the fan back on hit the reset switch and away it went again.

Then it started losing pressure way quick than usual. It would reach pressure ok but have to kick in sooner than usual - that turned out to be a leak around the cylinder which some teflon tape cured.

Then your problem happened and I thought - at last I can give it the flick but wanting to know why it was like it was I pulled the head off and I found the head gasket was cracked in 3 places. The gasket was some sort of Al foil which I replaced with some thin ally plate and it was good again. That was 2 years ago still going great.

BTW a couple of drops of dishing liquid in 250ml of water painted on the joints/fittings will reveal leaks that your ears cannot hear.

[Ueee]

I have a repco unit with an ingersoll rand pump. Some months ago it developed a leak in the pressure switch. A small bit of crap had gotten into the smaller line that runs up to the switch, and stopped the little valve in there closing. Same symptoms, had trouble reaching full pressure (150psi in this case) and having to cut in regularly. The worst bit was it was all but silent, I would have thought loosing so much air would have made a bit of noise but no....

Ew

[Hunch]

If you want something decent, have this for sale ~ 2k Also have a 2 cylinder Pilot that was pulled down thinking there was something wrong with it....if wanting something more nimble for 600...turned out to be a dud contactor.

Certainly wouldn't waste my time on the disposable imports, little one we have for rivet guns, can barely keep up with that use without running continuously.

[Ben Dono]

Thanks fellas!

Lots of good advice! I will have a poke around with it sometime this week!

It might be time for an upgrade soon anyway as I wanted to run some bigger air tools in the shop. Maybe a paint setup as well. As always money comes into it!

Anyone had a look at the Aussie 'Airmac' brand? Gasweld sell what appears as exactly the same line with a Toolex badge a fair bit cheaper. Did gasweld skimp on parts or is it all AirMac with a new sticker?

Are belt drives really that much quieter?

When I strip the old compressor down I will take some pics for the next guy!

[simonl]

While I'm a tight a**e when it comes to some things, I did buy a reasonable air compressor about 10 years ago. It's a belt drive with a fini (Italian) compressor. I bought it from All Tools. I looked at the direct drive units but decided on a belt drive since I had the money. I have never looked back. I have since seen direct drives in use and they are terribly noisy compared to a direct drive. Not much of an issue if you house them outside from the shed and plumb in the air but if they are in your shed then they would be very noisy.

It's still worth taking your direct drive apart to have a look. It may be a 5 minute fix. Why replace something if you don't need to. We still have a CRT television in the lounge because the bloody thing refuses to die! I see better TV's on peoples natures strips!

Simon