NAA lift cover

Needing to clean out the Hyd. Reservoir I finally talked myself into removing the cover (my first). Interesting device. Plan to check adjustments and take a look at the piston to see if original or not.

Some discoveries are a not fully tightened bolt on the Diff pinion cover. And what I guess folks mention as the Cam Follower pin appears to still be round. Wondering what the yellow paint signifies.

Also when I loosened the Large Acorn nut it didn't come off but is firm on the threaded portion of the bypass valve.
Should I apply a little force to see if it comes loose ?

The bypass valve left a good impression on the rubber seal.

Hadnt seen NAA lift cover that clean in years. Most are rusted up bad. The Yellow paint is for bushing OD, control valve spool has paint make too.

Haven't forgot about your battery box. Been a little under the weather. Grandson sick with special flu.

You don't need to pull the top cover to clean out sump & pump. Did you perform The Leak Down Test first? The test would tell you if the cylinder is worn. Unable to
sustain a load UP for weeks, months would be a sign of a worn cylinder. You need to remove ram to get the piston out. What are you hoping to tell if it is original or
not? What does it matter? The NAA-530-B with O-Ring and leather wiper is pretty basic. More importantly is the cylinder. Cam follower pin appears to have worn a flat.
Safety Relief valve would need to be replaced as well. Not a difficult task R&R'g the system, just time consuming. You went this far, if'N it were me, I'd go ahead and
replace the cylinder and piston now since the top cover is off. Got your Manuals handy?


Tim Daley(MI)

Shaun,Arlen, and Tim. Thanks for the replies.

Shaun. It is fairly clean, but the sump and Diff insides were a different matter. Hyd. Reservoir had quite a bit of sludge and the differential had layer of sludge under the remaining oil, but under that was a solid 1/4" of hard pack. I use a variety of tools for scrapping for both and for the Diff. I dragged out large chunks of accumulation I scrapped loose and (PTO was out), poured solvent in both. I was able to get my hand in the Diff and brass brushed all I could reach thru the PTO hole and vacuumed out both. PTO looks like it has two seals and leather.

Arlen. I hope you and GS are feeling better. Keep me in mind if you get a chance to look for the Bbox.

Tim. In my fool hardiness to renovate I only drove it around my driveway and didn't even work the Hydraulics, plus I have a Vane pump too. I don't know how much I need to get into the cover other than look at the piston and Cyl. for scoring, and check adjustments. Some here said the original piston could come out too far and damage the ring so I thought I should at least take a look. Safety valve and cylinder aren't too expensive, but is there something to look for other than scoring or damage Why replace ? Are there dimensions for cylinder bore and piston such as engine clearances ? I have MPC, FO19 and two other manuals.