We have an issue with the auto lubbers on our 2005 36z CIFA. It started really "squalling" on the driver's side piston/cylinder a while back. We discovered the piston was not coming all the way under the oil port and was not getting oiled. So far we have found no reason for this. Prox sensors are working correctly. It just switches 2" prematurely. So far the only thing I've done to find a temporary fix is to drill and tap the oil ports down the cylinder farther. The problem still remains. I replaced the piston. It had some hardened areas on it that obvioulsy happened from friction heat. It is the CIFA that also has grease certs. I have been greasing them and changing the water every day.  Within 100 yds of changing the piston it was doing it again - worse than ever. On my last pour it seemed to be siezing about 3/4 the way from the end of the cylinder. I would have to reverse it a few strokes in order to start pumping again after a brief time of nonactivity.

In a nutshell...

Why is the piston not coming back far enough to be oiled by the factory drilled oil ports? 

Why is the new piston siezing up?

Thanks for any help!

I have a Couple of suggestions, but a bit of a shot in the dark:

1.  If your cifa is a closed loop system, do you have a makeup oil problem between the hydraulic cylinders?  If there isn't enough oil in the closed loop, the cylinder without the prox switches will short stroke on intake from the hopper

2.  Try putting a slick pak in the water box or removing the piston all together and see if the problem lessens or disappears. If so, item 1 isn't the problem.  Many trucks don't have piston oilers and they only prolong piston life, but shouldnt prevent them from working properly.

3.  You said the prox switches are fine - if I remember correctly the cifas have a switch on the control panel that tells the pump to use prox switch set 1, none ( centered for greasing) or set 2.  Does changing the switch affect anything? I may be wrong on the function of that switch so don't assume I'm correct. 

Good luck. Just my 2 cents.....

Thanks for your input. 

It is a closed system. I need to look into your first point. I've tried a slick pack and that doesn't seem to change the length of the stroke. It does help with the squalling tho. I don't like to put it in for fear it will harm the hydraulics???? 

You are right about the prox sensors. It does not matter which set is activated.

One more thing to add to the puzzle. When I measured where the prox sensors first should sense the end of the stroke, it was a full 1.5 inches behind the piston, thus only oiling the piston rod and totally missing the piston. It almost seems it was made like that???