1965 255 massey ferguson left side engine steering pump

I had steering was out bushhogging went to turn and tractor did not turn. I checked fluid and it had a milky color. I drained fluid and put new fluid in did a burp on it and still have no steering. took lines off to check for air had solid fluid and pressure. put lines back on still have no steering

Welcome Jeff, hope we can be of some assistance, just a few questions...

I'm taking that this is a 255 model and the year was a misprint, as 255's weren't offered until 1975.

You're saying "no steering", as in no power assist, or the steering wheel turns and nothing happens?

Also, what type of steering does it have? Orbital motor? Power assist mechanical?

The milky oil was most likely air that was whipped into the oil, typically caused by low oil level. Was the level low?

Or it could have been water. If you still have the oil that drained out, take a look at it. If it was air, the oil will probably have, or is in the process of returning to a normal appearance as the air floats up and out. If it was water, some of the water will have settled to the bottom.

How did you check the pressure? With a gauge? Or just cracking a line and observing flow?

The only way to know for sure about the pressure is to remove the pressure line from the pump, install a gauge, start it up and take a reading. This will be a "dead head" reading, as the fluid has no where to go and will be bypassing the relief valve. Looking for around 2000-2500 PSI if I remember correctly.

Another way to make a crude pressure test, (which I only suggest to do at your own risk of damage) is to wrap a rag around the pressure line that comes out of the pump (NOT the return line!) and with the engine idling, gently clamp the line shut with vice grips. You should see the hose swell, hear the pump load, and hear the engine load. If nothing happens, the pump would be suspect. But, those pumps are simple, typically they either pump, or they don't, nothing in between.

I've never had to bleed the air out of a power steering system. Air might be noisy, but it won't stop it from working. It will eventually work it's way out, usually overnight when sitting.

If this is an orbital motor steering system, and you decide to take the steering motor apart, be extremely careful to mark EVERYTHING as far as housing orientation. The one I took apart (only to replace seals) would reassemble in many, many ways, but only work when right! BTDT, don't want to make that mistake again! LOL

If you are going to tackle this, or any other project on this tractor, a shop manual will be an extremely valuable investment! Will more than pay for itself in mistakes not made!

If that is an assist type steering deal, if it has a reservoir like a car there is a filter in there possibly. That could be plugged.