The Grease cup on the GX CS4 is crap.......

I checked mine today and found that the black membrane was off center about 1/4 inch with no rubber between about 1/2 of the pistol assembly and the part on the compressor. It was apparent that grease had been finding its way into the hole anyway. I removed the membrane completely. I did not notice any grease coming past the metal piston assembly and the part on the compressor despite not having the rubber seal between them.

Not sure how much I should turn the dial now without the flow regulation. Probably 3/4 of a turn? I am going to contact GX Pumps and see what they have to say.

That membrane needs to be about 1/8" thick on the outer edge for about 1/4" in from the outer edge all around, then thin like the original one with the pinhole in it so it will stay in the proper position.
 
After pulling mine apart I have found that the membrane is working as a diaphragm so the screw forces a little grease through the hole in the membrane then a small amount of air pulses the membrane working the grease to the larger hole in the body where it is pulled into wherever it needs to go. to see this working pull the grease cup leave the membrane in place and run the compressor without a load.
 
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I did end up machining an aluminum disc for the grease pot in my CS4....I machined a dish in the center of the disk towards the hole and left a rim on the outside for the grease pot to seat against. When turning the knob, it will direct the grease to the hole in the center of the disc to the hole in the compressor. The rim on the disc is perfectly flat and will allow the grease pot to seal to the rim without the need for a gasket. I think it's going to work well, no more warped rubber gasket blocking the grease hole in the compressor.

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I did end up machining an aluminum disc for the grease pot in my CS4....I machined a dish in the center of the disk towards the hole and left a rim on the outside for the grease pot to seat against. When turning the knob, it will direct the grease to the hole in the center of the disc to the hole in the compressor. The rim on the disc is perfectly flat and will allow the grease pot to seal to the rim without the need for a gasket. I think it's going to work well, no more warped rubber gasket blocking the grease hole in the compressor.

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How is this working? Would you sell one?
 
I took off the zerk on my CS4-I pump. It's dry. No grease was pumped thru it. There is the light tan "GX pump" grease down towards the bottom of the cavity though. I'm not sure the zerk solves much. I'm not gonna have a grease gun with special grease cartridge dedicated to this pump. That seems overkill. I'll probably order some of the syringes with the GX pump grease and use that. I could just remove the zerk and apply the grease directly from the syringe with needle tip.

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Here is what I did to my CS4....I removed the grease pot and cleaned everything up. I took the grease plunger apart to see how it is made, it's a brass screw held by a clip so it's free to turn, an aluminum disc with an o-ring with a threaded hole in the center and a conical spring to hold pressure against it. I just took the rubber disc and cut a large hole in the center of it and trimmed it to fit in the bottom of the grease pot to act as a gasket to seal the bottom of the plunger housing to prevent any grease from leaking out up through the threads from the bottom of the plunger. To find how many turns there was on the plunger, I screwed it all the way up in the barrel housing and I threaded back in seated tight against the rubber gasket, I put a mark on the knob and counted the full turns until it bottomed out and got 25 full turns on the knob.
I see no need for that full size piece of rubber with the small hole in the bottom that's supposed to be a grease limiter, how can it limit the amount of grease when it swells up and distorts and the hole is no longer aligned. with the hole in the bottom of the grease pot and it's being compressed with grease against a perfectly flat bottom...??? I salvaged what grease I had left and put it back in the plunger, I have 7 turns left on the plunger before I need to refill it with grease. I'm going to order some new grease and refill the plunger and use it like this from now on .....Sorry for the long post......

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Do you have aluminum disc for the grease pot in for CS4 In stock for sale.
 
It was mentioned that the grease pot uses the rubber washer as a pump or one way valve, and others say take it out and it runs fine without it. I'm confused about which to believe. If I turn the grease pot knob every 4 hours and can physically hear the pump change sounds, can't we assume that our grease pot is working correctly? If we can add our own grease with a syringe at 4 hour intervals, why would we even need the grease pot? And is there a special kind of GX grease? Or is it something we can get at any auto parts store or online?

Thanks
Ray
 
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