Cat pump low pressure

[stampedecarwash]

Hello, in one of our cat pump for wandwash, we had a leak yesterday due to low pressure seal failure. Changed that and no more leak. Today noticed pump pressure is about 1000 psi while it’s usually at 1150. And yesterday right after the change it was all good. So adjusted the regulator to bring it back to about 1150. Now I see a big difference ( about 300 psi) between when the gun trigger is held and when its not. These are weeping guns. I have changed this head 2.5 years ago with one of those Cat replacements head since they changed it for you for free for one time only. Since then no issues until yesterday.
My first thought was one of the low pressure check valve has failed and water going somewhere else and thats why low pressure (1000 psi). But I dont see any high pressure in my low pressure function gauges or spot free. I have a Super Savor system. Also checked the belt between motor and pump and it looks fine.
Maybe the head is going bad again? Or maybe when I did the new seals I damaged the seals? You know its hard to push them in on high pressure seals. I didnt see a significant wash out in the head when I changed the seals yesterday.

thanks,

 

[$!cmad3k]

I always change all seals on cat pumps if any of them are worn. Youre unloader could be wearing out. Check cages and o rings on the check valves. See if there is water mixing with the oil. Make sure none of the plungers are cracked. What model cat is it?

 

[stampedecarwash]

Thanks, its cat 2120 pump. Yes I changed all seal. My experience with unloader is they go bad when they start leaking. Didnt check the valves since no vibrations. Also didnt see cracks on the plungers.

 

[$!cmad3k]

Thanks, its cat 2120 pump. Yes I changed all seal. My experience with unloader is they go bad when they start leaking. Didnt check the valves since no vibrations. Also didnt see cracks on the plungers.

5cp2120? The plastic cages on the check valves can wear and flex. They wont let the spring fully compress. So you wont always feeling pulsation.

 

[stampedecarwash]

UPDATE: I was just watching that pump and it had too much pressure around 1300psi because I adjusted the unloader in the morning. Now adjusted the loader back down lol. And dont see a big difference between squeezed and not squeezed trigger, which is perfect. I guess sometimes you just have to ignore things and they fixe themselves ???lol

 

[$!cmad3k]

UPDATE: I was just watching that pump and it had too much pressure around 1300psi because I adjusted the unloader in the morning. Now adjusted the loader back down lol. And dont see a big difference between squeezed and not squeezed trigger, which is perfect. I guess sometimes you just have to ignore things and they fixe themselves ???lol

Sounds like a little piece of something got in the unloader then cleared out.

 

[stampedecarwash]

Sounds like a little piece of something got in the unloader then cleared out.

Maybe adjusting it helped the little something to go through… and pass. Perhaps while changing high pressure seals some of pieces of them got to the head. I have to crash these seals to be able to remove them even with reverse plyer.