Ok, have a supercheap air compressor (I know) that has started to fail. I only really use it to pump up the odd tyre or blow out carb jets etc but it is annoying me that it is not working after so little use: Especially as I would like to use it on my new media blasting cabinet, but cannot deal with the noise (and power use) as it never shuts off. Symptoms are:
Does not get up to pressure, keeps pumping but needle won't rise above 28psi, so pressure switch does not activate.
I have had the head off and cleaned the little flap valve things, and reassembled. No leaks anywhere and the tank holds pressure, but it won't get to a high enough pressure to be of any use. The motor appears fine, I've drained any water out of the system, and it is full of clean oil.
I realise I could lower the switch pressure and it would supply say 20 psi ok, but that is no good for tyres.Is there anything that can be done or is it really a throwaway job.!
edit: I have also replaced the regulator with a proper one, but that is downstream of the main pressure tank/gauge so not the problem. Even with the valve shut the tank never gets up to pressure.
bitsy_boffin,
Nov 20, 5:33pm
Did you have a look at the piston rings while you had the head off!
Did you replace the head gasket when you had the head off (just make one our of a bit of card or something)!
Did you put the valve-plate back on the right way up!
They are not complicated machines, piston goes down, piston goes up, either a "valve" is not closing, the piston rings are not creating a good seal, or there is air leaking out somewhere.That's about all it can be eh.
elect70,
Nov 20, 5:34pm
Direct drive orbelt drive . Belt drivesgo for decades but those direct drivesrun at hi speed . Sounds like the reed valvesstuffedask SC if they have replacements .
kazbanz,
Nov 20, 6:05pm
Sifty. In all honesty mate I just wouldn't bother. Heck take it back to where it came from and get another unit under warranty
rob_man,
Nov 20, 6:11pm
I had one of those do the same thing anda mason bee had blocked up the inlet in the head. The compressor had fallen over at some stage and broken off the air cleaner so there was nothing over the hole.
sifty,
Nov 20, 6:25pm
Ta for suggestions.
1) A few years old so prob not a warranty thing (I replaced the first one I got incidentally as it seized after about 2 mins running, and yes it had oil). 2) Rings was my first thought after I had checked the reed valves, I was hoping to find a bit of crud under a valve but they weren't too bad. I will double check inlet is clear, but pretty sure it is as I had air filter off. 3) There was a thin metal sheet which I assume was the gasket. It seemed ok and there is no external leak on reassembly, but I was intending to make a paper one if I go in again 4) if it is rings, are they available for cheap items like this! Guess I should just call SCA.
cheers.
(I had to google mason bee, thought it was some technical term or jargon I wasn't aware of).
m16d,
Nov 20, 6:48pm
Yer. my supercheap one did that too. Wouldnt pump up or stop. Turned out is was an air leak on one of the external pipes because it hadn't been flared properly. Turn the thing off so the noise goes away and have a good listen for leaks.
sifty,
Nov 20, 7:18pm
I've soap bubbled and listened at all points I think, will have another look though, seems likely there is a leak somewhere I haven't found, cheers.
rob_man,
Nov 20, 7:23pm
If you really must go as far as new rings, Johnson (or Johnston or Johnstone) Engineering in Penrose make all sizes.
thejazzpianoma,
Nov 20, 7:30pm
I have seen two Chinese cheapiesgive trouble, this was a while ago so I am a bit fuzzy on it but I think both times it was a non-return valve which was located in a union between the pump and the tank. It was obvious what was wrong when I took the joint apart and very easy to fix, no parts required.
rob_man,
Nov 20, 7:39pm
That's where I'd be looking too if the reed valves are OK.
sifty,
Nov 20, 8:14pm
That sounds promising.
shoedoos,
Nov 20, 8:45pm
Trying not to hijack.but, where's a decent supplier of spares for compressors in Auckland! I had another string going about an Abel Cooke compressor. They don't exist anymore and I'm looking for a capacitor for one of their direct drive models.and by the way, Johnsons Piston Rings is owned by Franklin Engineering out in Pukekohe nowadays.
sifty,
Nov 20, 8:59pm
So in summary, I'll check the location/condition of the non return valve, retest for external leaks, and then pull down again to check rings. If these are ok I'll make a new gasket, reassemble and retest.
After that I'll chuck it in a skip and buy a new one if it still isn't right. It is only out of interest I am keen to look further, as if things are going round and round, and up and down there must be a simple to find fault somewhere. There comes a point however when my time is worth more than the replacement cost.
cheers to all.
hijacka,
Nov 20, 10:30pm
Sounds like its the non return valve as mentioned above. usually theres abit of debree stuck in the valve stopping it from closing, ive seen bits of alloy casting and dried glue stuck in there before causing the same fault, so follow the air line from the head to the tank and undo the valve thats bolted to the tank that the airline goes to, remove it and check it over thoroughly.You can order replacement parts from super cheap but may take some time to arrive
richard198,
Nov 20, 10:35pm
Abel Cooke are Australian so I guess your best bet would be Ash Air in Glenfield.
bitsy_boffin,
Nov 21, 12:30am
It's still useful even if it doesn't go, even if you just keep the tank and connect it to your new one for extra capacity.
sifty,
Nov 21, 12:40am
yep, just got catalogue from supercheap in the mail, new one available for $129 with tool assortment. Think that's what I'll do.
checked non return valve incidentally, seemed sound, simple soft compound washer held with a spring, no crap in there so may use it for parts. I'll update if I pull it apart further in the weekend.
andrewph,
Nov 21, 12:43am
Drain valve on the bottom of the tank !
sifty,
Nov 21, 12:45am
checked, let a lot of grotty water out but seems closed ok now.
easygoer,
Nov 21, 2:12am
Remove the head and separate the valve plates, there are three gaskets, the lower gasket is a circular gasket and seals the lower valve plate to the cylinder, the next is a metal shim plate between the valve plates and the final gasket is between the head and top valve plate, either the shim plate or most likely the top gasket has blown between the inlet and outlet chambers, ring the 0800 number on the compressor and they will direct you to the local service agent who should have the gaskets, we sell the set for around $15.00
i-n-horz,
Nov 21, 4:28pm
If you weren't so far away sifty I'd let ya borrow mine.I've just had it rego'd for some summer cruizin ;)
richard198,
Nov 22, 5:03pm
Why persist with these cheap models from Supercheap! Do yourself a favour and get something decent, that won't break a day after the warranty expires!
skin1235,
Nov 23, 12:37am
no-one yet has mentioned it so I will They also give trouble in the unit which is the base of the pressure switch ( that black box thing), I've come across broken pipes and blown 'O' rings in them before you can use a spray bottle to squirt soapy water up under there - yes there are electrical connections in there but they are well protected - and believe me if there is any leak in the area it doesn't take much soap to make it show up. they have a pressure release port under there to unload the system until the motor gets to working revs, and release the final stroke when the motor shuts down - that common pwiish sound we all know as the motor stops the non return valve as mentioned before issues, are often due to swarf, from either threadings or drillings not having been cleaned properly - they can also be an issue in the pressure switch area, these swarf pieces tend to hold the pressure release port open and thus the pump cannot get full pressure to the tank
skin1235,
Nov 23, 12:44am
does it matter if your dinner tonight was served on a warehouse $16 dinnerset or a $600 Windsor china set,-- I bet the food tasted the same heaven forbid you may be using a stainless fork rather than a true blue stirling silver jobby
there is nothing wrong with a supercheap tool of any type, in fact I've found them to be a dam sight easier to source parts for and repair than some of the fancy double westinghouse flash 22cfm that are often used as the benchmark buy by loyalists/royalists with no logic apart from a feeling of elitism
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