5cp2120 rebuild

[Reds]

I have a Cat 5cp2120 pump on my SS stand that is 5 years old. It has water in the crankcase (oil is whiteish and foamy) but sounds fine and produces good pressure. I am not familiar with these pumps and plan to rebuild it but the only parts kits I see on Kleenrite's site is the seal kit. Are there other parts I should replace while I have it apart? Does anyone know of a source for any other parts needed.

Thanks for your help

 

[I.B. Washincars]

First, I would just change the oil a couple of times pretty quick and see if it comes back quickly or not. If you are anything like me and never change the oil, it may just be from condensation. I don't think that bad seals in the manifold will let water into the crankcase. When the low pressure seals start leaking the water runs out onto the floor. If it were me I would install a seal kit, change the oil, and forget it. I have yet to see water in the crankcase cause one of these to grenade.

BTW, if you post this in the SS section you will probably get a lot more help.

 

[MEP001]

Are there other parts I should replace while I have it apart

Since there's water in the oil, the springs on the oil seals are probably rusted. A seal kit comes with new washers for the plunger bolts - replace the washers and the piston oil seals and change the oil a couple times. Inspect the plungers carefully to make sure none of them are cracked.

Like I.B. said, the low pressure seals being bad would cause water to leak from under the manifold. I've seen it bad enough to get into the crankcase, but if it isn't leaking onto the floor it isn't those seals that are your problem.

Even if it's rnning fine noe, don't leave milky oil in your pump - it will ruin it.

 

[boywonder]

Sounds like you need some good crankcase seals to me. I had about 5 of these right after they had come out. All needed crank seals within 4 months. Save your money and switch them out to 310's.

 

[MEP001]

Crankcase seals only keep the oil in; they do nothing to keep water out when there's another issue.

Cat did have a problem with the crankcase seals failing when the 5CP first came out, but they solved it long ago. IIRC it was a machining problem with the piston.

 

[I.B. Washincars]

Save your money and switch them out to 310's.

If you really want to save money, switch them out to Arimitsu. Very reliable, very quiet, less up-front cost, no special tools needed, and tech help from Greg, right here on the forum. When was the last time a Cat tech chimed in? Or even the first time?

 

[Greg]

If you really want to save money, switch them out to Arimitsus. Very reliable, very quiet, less up-front cost, no special tools needed, and tech help from Greg, right here on the forum. When was the last time a Cat tech chimed in? Or even the first time?

Thanks I.B.......I appreciate the opportunity to help you and other folks in the business.

Greg Thoennes
Sales & Tech.Support
Arimitsu Pumps

 

[Reds]

"Like I.B. said, the low pressure seals being bad would cause water to leak from under the manifold. I've seen it bad enough to get into the crankcase, but if it isn't leaking onto the floor it isn't those seals that are your problem."
Yesterday it started leaking water out the bottom of the manifold. Seal kit came in late yesterday and I will rebuild it today.
Thanks to everyone for the input

 

[MEP001]

I still suspect your plunger seals - they're included in the kit. Make sure you replace those while you have it apart.

Here's the service manual which contains the torque specs:

http://www.catpumps.com/select/pdfs/CPSvc.pdf

 

[Reds]

I replaced all of the parts in the kit and it is running fine. thanks for the help.