300U Hydraulic Dipstick Reading???

My 300U has its hydraulic reservoir under the seat. Near the front edge is a pipe-plug type cover for adding fluid, and attached to the cap is a dipstick a few inches long for measuring "full."

Here's my question: Am I supposed to screw the cap in all the way to accurately measure fluid "full" -- or do I measure by just setting the cap in the hole and not screwing it in at all??? There are maybe 3/4" of threads on the cap, so screwing it in might show it "full" while not screwing it in would show it pretty low.

My owner's manual is silent on this point. Help please! And thank you in advance.

Bob Kirk

I'm curious about your comment about oil coming out the vent. By "vent," do you mean the "breather" that sits on top of the reservoir or someplace else?

I've recently had oil spitting out around a snap ring on the top of the safety and flow control valve. This has coincided with my Hydra-Touch valve not working -- so I've figured something is clogged up and I'm about to rip things apart to see if they're full of dirt.

Thanks again for your reply. So far, its a flat-footed tie -- one to one -- on which method to use!

Bob