Ih 1586 hydraulic problems

I have a1977 ih 1586 that's been giving me fits, hydraulic pressure is really weak at the remotes and when you use the remotes you lose steering brakes and clutch. I have replaced both pumps new oring and seals in both areas, hasn't changed a thing, I'm stumped, anyone else have these issues?. Also new fluid and filter

Maybe suction tube sealing/"O"ring issues????

Fill it 5 gal. overfull of hytran/UTF and see if things get any better.

That year would be open center hydraulics. Therefore the hitch pump supercharges the mcv (steering and controls) pump when hitch and aux valves are in neutral.
When you use aux valves the flow to mcv pump from hitch pump stops so mcv pump has to pull it's own oil. I say you are sucking a lot of air. There is a o-ring seal between transmission and rear section on the suction tube. Also, make darn sure the suction tube and seal at hitch pump is in properly installed with lip toward pump and in good shape. Lots of times , people replace the hitch pump and not the seal and also the only correct way to install that short jumper tube is from the filter side after the pump is loosely installed for proper alignment. You may try over filling with about 5 gallons of fluid to see if that helps. That will cover the tube between sections. Also, make sure the main suction tube to rear is no loose flopping around. There is a o-ring on that tube also where it enters the filter housing. Last but not least, o-ring on filter cover, some do not fit well and suck air in.

So when the mcv pump pulls it's own oil where is it supposed to be pulling from?

It pulls it from same filter, note the passage in behind the retainer that rear of filter fits into. That passage leads to mcv pump. You need to take that retainer out to install the pump suction tube to rear pump and then that passage is visible.

Replaced to suction tube seal helped out the speed of the hydraulics a BUNCH still loosing all other controls when I use remotes though, haven't over filled yet didn't have enough fluid but I will tomorrow, any other thoughts ? Do you think maybe blown oring in the mcv block or maybe the block needs rebuilt? By the way it's a factory non-TA don't know if that matters

I bought a 1256 once that had a cab. There was a $.75 plastic peice that went bad and you had to remove the cab and top off the rear end to fix it. That only cost $350 back in the 1970s. I did get it sold and made some off of it.

First I would over fill and hopefully that will help you out. If it does not, I know what I would do. I am always into my own style of trouble shooting. I would put a hose in one set of couplers on the rear and tie that aux valve back to allow all flow from rear pump to circulate. This will cut off the super charge to front pump. Then I would take the super charge line off down at the mcv, plug the line and cap the fitting. If it still does not pump, time to pull mcv and inspect. Also attempt to find any suction leaks for that pump but that gets pretty difficult as you would need to plug off other pump inlet. Can be done though. Now, if the mcv pump works ok with the plugged and capped fittings, well, some where up in the valve block is allowing air to enter. IH at one time did give instructions to remove the supercharge line when loss of mcv functions did happen when using aux valves. Problem is, I never found out really where the problem actually existed to cause the interruption. It was most noticeable when someone was holding down the clutch pedal, then he actuated a aux valve and clutch pedal pushed his foot back. Not good in close quarters.

(quoted from post at 01:32:48 08/17/14) So when the mcv pump pulls it's own oil where is it supposed to be pulling from?

Click to expand...

You did replace the filter I hope.

Both hydraulic pumps draw oil through the same filter. The MCV pump is rated at 12 gpm. The hitch pump is also 12 gpm. The flow from the hitch pump is routed to the MCV pump through the supercharge line if neither the auxiliary valves or the hitch is being used. Total flow through the filter will be 12 gpm. When either auxiliary valves or the hitch is being used the flow is cut off from the supercharge line to insure that no unfiltered oil returning from the auxiliary valves is allowed into the MCV. The flow through the filter will nor be 24 gpm instead of 12 gpm. This is even greater if you have a 17 gpm hitch pump installed. Any restriction from a dirty filter will make any possible air leaks much worse.