A buddy of mine has a international 240 and the 3 pt hitch only raises about 1 inch off the ground when we hook up a box blade. Do we have air in a line or something? Please help, thanks.

Well I don't know about the International, but I've seen a Massey 135 that had a filter noone knew existed, so it had never been replaced.

The tractor beeing over 40 years old, the gauze filter had degraded and was sending bits into the system, with the consequence that the hydraulics were choppy. Sometimes you'd loose the steering for a bit...

The folks at Yesterday's tractors forums explained to us that accessing the filter on the 135 requires the removal of some parts in the transmission, and the unless you have a manual or know how they go, you're likely to replace something not quite right and then break something when trying to run the tractor. Flushing the system helped quite a bit.

Yesterday's tractors is a website devoted to this kinda stuff. They helped with the International 27 baler, too.