I received a call for a Dover lift starting rough. What we found is the oil in the tank is dark. And the cylinder is dry. We could see an improvement when we wiped a little oil on the cylinder. But that was a temporary improvement. We loosened the head and snugged it back. We adjusted the valve for a softer start with little improvement.

I'm confident the oil viscosity is breaking down causing the packing to stick. My question is a simple one...
What weight hydraulic oil did Dover use in their units?

get some CAT OIL or Metalcoat, its an additive you put in the oil it works wonders!!!!! yes that is CAT as in Caterpillar machinery

Thanks Bill,
This elevator was installed back in 1983. I'm sure it the original oil and likely the original packing. We have had this elevator for a short while now. And this rough ride just started. This type of repair is not included on their contract. So the burden of the expense is on them.

So is adding CAT oil a cure or a temporary solution?

Send the oil out for analysis, provide the results and replace if required.

tellus 32 is the hydraulic oil weight we used on most jobs. Your right to replace the oil, it more than likely been cooked many times in the last 30 years.

All correct points. Dark oil is dirty oil. Filter it correctly until contaminant free. Empty tank and clean it thoroughly. Have valve replaced if eeco (i personally hate those piles of junk scrap) or rebuild if it's a maxton uc4.1983 vintage might have a uc3. Upgrade if so. If packing isn't leaking, I'd leave it alone. Viscosity of hydro oil doesn't change unless it's boiled, and you'd definitely be aware if it was. The smell and charred pump/valve would be unmistakeable. Cat additive is a temporary fix for a bigger issue. A thirty year old valve and pump cannot be expected to produce like New ride quality.

We use 68 oil for our hydraulics and if there is any darkness we drain it and replace it.

Cat oil is great for packing that are too tight and cause ruff starts. Here is a great trick I stole from the PVC around new jacks. When you get a job that the oil has been contaminated with water, scorched from overheating or just plain worn out and needing replaced. How do you get the oil out the jack??? We remove the oil line from the jack and hook up a short pipe with a 2 inch vic plug on it. We have several threaded to vic and several vic bell reducers for any size oil line. The vic plug has a threaded hole with rigged push on hose connectors. Use rubber flexible hose. Weight one end and drop it to the bottom of the jack between piston and the jack. The other side of the plug hook a hose and run out of the pit to MT 55 gallon drum. The second hole in the vic plug has a quick air chuck for a compressor .vic the plug to the jack so you have a closed system. It only takes 4 or 5 lbs of pressure to MT the longest of jacks. Simple and works great.

Just wanted to add this is how we get oil out of the jacks before jack replacement also. Of course you will want to follow all standard safety practices before opening the oil line. Good luck , and work safe.

Always great advice!
Thanks Dan

Thanks Brett

Philly & John too
,

No probs mate.