pump still pulsating

[jnoden]

I posted this problem a while back and after a few attempts to fix the problem I unfortunately still have the same problem. The pump is a belt driven T series General Pump 5.5gpm 3500psi. It only pulsates and has less pressure when I try to tank feed it or if the water pressure to the inlet is not high. I have replaced all the valves, flushed the pump with the valves out, replaced the inlet filter and use a larger diameter hose to the inlet. I have another machine fed from the same tank with the same exact connections and hose and it runs fine. The one I am having problems with use to pull from a tank just fine. At this point I might be buying a new pump but it is hard for me to spring for a new one seeing that this one is only 2 yrs old. I thought I would post one more time to see if anyone had any other ideas.

[FullBlast]

Has it done this from new or has it just started to do it?

I changed one of my pumps awhile back with I forget what number of General pump and it would not work off a tank application. So I sent it back and got a different model and it works good.

[Russ Johnson]

Jim, sounds like an air leak of sorts on the inlet side of the pump...possibly a bad low pressure seal or a cracked plunger, possibly a bad o ring on the first seal retainer. Yank the head off, check the plungers for cracks (should appear as a dark line running lengthwise on the plunger), check the first seal in the head for fraying, raggedness, etc, check the o ring on thefirst piece of brass that you pull from the head. Also check the face of the aluminum crankcase where the brass rings sit. It should be flat and on the same plane as the rest of the crankcase. If it shows signs of movement from the brass ring(a circular divot around the hole where the piston comes through), then you can rebuild it all day, and it's still going to screw up because the brass ring is allowed to move, fraying the o ring. If you like, take some pics of the disassembled pieces and email them to me, or post them here. It might help.

[Douglas Hicks]

I thnk Russ has the right idea, an air leak on the intake side of the pump. Titen the hose clamps or replace them. You may have an air leak at the intake fittings also. Is the hose fully on the air fittings?

[jnoden]

I guess it wont hurt taking it apart since it will be junk to me if I dont get it fixed. I like taking things apart and I am good at it its just getting it all back together the right way that is usually my concern. Anyway, Ill have a go at it and see what I can come up with. Ill try to take some pics. Thanks for the quick replies fellas.

[Doug T]

If you have an upstream injector, you might want to take it off and plug the hole to eliminate any problems there.

[FullBlast]

Good point there on the injector, I had that problem one time, and seen others with the same.

[washum]

Hi Jim
I fix many machines with that same problem,I found the problem to be warn pump packings.The inside seal close to the crank case ware and cause a vaccum leak. Its a $100 fix.
Good luck

[PPC]

I've had this problem sounds like packings