Cat 530 Plunger Rod

[Twodose]

I have never seen this before on a 530 cat pump, where the plunger rod is discolored like that, it was a little difficult to get the plunger off, where as they usually just slide right off.
The plunger retainer o-ring and backup ring were in good shape, but it is obvious it looks like water was getting in there somehow.

 

[MEP001]

Yeah, that's rust. Make sure you replace the copper washers any time you remove the plungers. Inspect the plunger for cracks before you reinstall it. It's really rare that a 530 plunger will crack, but it does happen.

 

[Twodose]

About a month ago I replace the HP, LP seals on the manifold, the o-ring, backup ring and copper gasket on the plunger, torqued everything to spec, now a month later, there is water dripping slowly on the right side of the pump were the rusted plunger rod is located, it is dripping on the bottom where the manifold and crankcase come together, I am assuming it is coming from that plunger, my question is, would that be the location the water would be dripping from if a plunger was leaking?

I have never come across this before, the pump was installed new in 2013, they have a tech bulletin, 045 and 074 about the newer style plunger retainer, I have some of them, so I guess I will try replacing the o-ring, backup ring, and copper gasket again, with the newer style plunger retainer.

Also the plunger looks like it is in great condition, there are no visible cracks, thinking that maybe I should replace the plunger, even though it looks good there must have been a problem maybe from the factory.

It wasn’t leaking before I replaced the HP,LP seals…lol, found that when I took it apart.

 

[MEP001]

It could be leaking from the low pressure seal now. If it only leaks when the pump is running, it might be the plunger or plunger seals, but if it leaks all the time it's the low pressure seal.

There should be a slinger washer and split washer on the piston that aren't in your pictures above. Did those get put back on? Did you use threadlocker on the piston bolt? I usually don't, but it can back out and cause a leak.

 

[Twodose]

It only leaks when the pump is running. The slinger washer and split washer were put back on, I left them off for the picture. No threadlock on the bolt.

 

[MEP001]

My guess would be a bad plunger or possibly the bolt. I'd replace them both.

 

[Twodose]

Took this apart today to fix the leak, replaced both the O-ring and backup ring, put in a new ceramic plunger< actually an old one that I had laying around, and a new plunger retainer bolt and copper washer, after removing the head, that same plunger had play in it from front to back, very slight, you could move it back and forth just a little bit, it was not solid on there like the others, before replacing the plunger I tried to tighten the plunger retainer bolt, but it still had play, everything was torqued to spec the first time and this time. Looking at the plunger there was no cracks or anything unusual, set the old one along side the new one and you couldn’t see any difference in the length.

This is the first time I have ever come across something like this, and like to post back in case anyone would have the same problem in the future.

Last time I fixed it, it took about a month to start leaking, but it slowly got worse in the last couple of weeks and was dripping allot, so we will see what happens.

 

[MEP001]

The plunger is loose on the steel rod even after torquing? It's not unusual for there to be a tiny bit of play from a loose fit of the connecting rod around the crankshaft, but if you can spin the plunger by hand you're just going to have to keep replacing the seals. You might try finding a bottom tap, might be hard to find in the correct Metric size, or cut/grind a little length off the bolt threads in case the piston wasn't machined properly and the bolt is bottoming out.

 

[Twodose]

When tourqued the ceramic plunger would move on the steel rod, the rod wasn't moving, just the ceramic plunger, after replacing the ceramic plunger, no movement.

 

[Erik_Catpumps]

Can we get any pics of the retainer/inside of the plunger?
Be interested to see what those look like.

 

[Twodose]

I don't know how you could take a good picture of the inside of the plunger, but this is the best I could do, obviously it is a factory default, I have never seen this before.
Also, everything was clean and there was not debris on the plunger or the plunger retainer a month ago.

 

[Erik_Catpumps]

Yeah, its tough to get pictures that can really confirm whats going on with something like this.
Not seeing any defect, but we would be happy to look at it here to get a more detailed review of the pump.