Hi Folks,

Mr. Schweibert asked me to post over here about the problem with my dad's 550.  So here it is...
 
I think the power steering pump may be shot on dad's 550. The tractor is the 1969 model that has PS driven from the engine, not attached to the generator. Problems are that it spits fluid from the filler cap on top of the hood and when I try to turn the wheel it turns easily just a bit (like the PS is working), then it is stiff (like when the engine isn't running). I suspect that the initial easy operation is due to slop in the steering linkage until the slack is taken up. The pump has had a leak for years at one of the hose connections, I'm assuming the pump outlet (under pressure), which caused us to continually keep an eye on fluid level and top off as needed. I suspect that different types of ATF were added that may have damaged the seals (or whatever mixing types causes). 

Is there a filter that may be blocked that may, mercifully, be able to be cleaned that might solve the problems? Any other ideas that might cause these symptoms? 

Failing that, can I assume from the posts I've seen that Agco doesn't offer a replacement pump? I think I read somewhere that the pump is a Chevy model from a certain year. Does anyone know the specific model and year so I can order one if needed? 

Thanks for any help you guys can provide. 

Buck's550