Hi there so I have a concrete mixer truck I'm working on with a PVP 16 piston pump to control the chute and bridge master on the truck. It's supposed to put out 3000 PSI and I'm only getting 500 out of it. I can make PSI go down with the adjustment bolt on the compensator but I cannot make it go over 500 PSI. I had the spring compressed all the way and it still didn't go over 500. I had the compensator and pump apart multiple times now but I cant see anything wrong It all looks good as new. Am I missing something? I didn't mess with It before this happened it just stopped working out of the blue. Any help would be appreciated.
I had a pump something like that where the linkage for the swash plate angel broke. It would only make about 1,000 PSI in a telehandler.
So I found the problem after taking it apart again (see pic)...I'm kind of new to this and didn't think those scratches could be the problem when I took it apart at first. I used a flat surface and some 1200 grit sandpaper to smooth it out and now i can get 3000 PSI. But I have to give it some throttle to get up to that pressure so I will probably have to get a new plate
A machine shop may have a flat hone that could precision surface it for you.
You can use some fine lapping compound between that valve plate and the piston and barrel assembly to get it smooth enough. You will have to do that even if you get a new valve plate.
I would never use lapping compound on a soft metal such as brass or bronze. It will embed.
If it won’t go above 500 PSI even with the compensator spring fully compressed, I’d start looking somewhere other than the adjustment itself. Could be an internal leak, a relief valve stuck open, or the pump just isn’t building pressure anymore even though everything looks good visually. I’d also check the suction side for any restriction or air getting in. Since it happened suddenly, I’d suspect a valve or seal failed somewhere rather than the adjustment getting out of spec.