MF 285 Hydraulic Pump

[ford401]

I had no PTO, 3 pt, or remotes on this 285. Figured it was the main pump that went bad. I’ve got the tractor torn apart and was hoping to just order and throw a new main pump as well as a new aux pump in it. The smaller aux pump was easy to find, But now I can’t find the correct replacement for the bigger one. Anyone know where to find one? If not, who rebuilds them? AGCO dealer said they can’t get it.

Not familiar with these style pumps, didn’t really want to spend $300 on a rebuild kit (if they make one) then put it back together and not have it work since it’s so hard to get to.

 

[Bob NY]

The main pump provides the pressure for the 3ph. The auxiliary pump provides the pressure to the pto clutch pack and probably the remotes. Since everything stopped at once, I would be suspicious of a failure of the shaft that splines into the clutch cover and drives the lower transmission shaft.

 

[ford401]

The main pump provides the pressure for the 3ph. The auxiliary pump provides the pressure to the pto clutch pack and probably the remotes. Since everything stopped at once, I would be suspicious of a failure of the shaft that splines into the clutch cover and drives the lower transmission shaft.

I figured the big pump ran more than just the 3 pt. but that’s good to know…the splines on everything i took apart look good.

 

[Jim.ME]

I figured the big pump ran more than just the 3 pt. but that’s good to know…the splines on everything i took apart look good.

I believe you will find the "big" (main) pump has a lower volume output than the "small" (auxiliary) pump. Output, not size, is what counts.

Unless you have taken apart more than in your pictures, you haven't gotten to the splines Bob is talking about, you need to look at the clutch, pressure plate, and transmission input shafts, to see those.

 

[Dieseltech]

You should have done some testing before tearing it apart. The Scotch yoke pump is for the three point ONLY, the Auxiliary pump is USUALLY a TWO stage pump, the larger side supplies the cylinder valve, and the smaller front section supplies the PTO valve and MP valve if tractor has the twelve speed MP option. The PTO INPUT SPLINES at the FLYWHEEL if stripped out will stop ALL the PTO/ HYDRAULIC drive at the rear of the tractor.

 

[Dieseltech]

As an OLD MF mechanic I would try this. See if the lower transmission PTO drive will make the engine turn, it SHOULD. If not remove the lower plate under the flywheel and see if the PTO input splines are stripped, OR the drive hub rivers are sheared.

 

[ford401]

As an OLD MF mechanic I would try this. See if the lower transmission PTO drive will make the engine turn, it SHOULD. If not remove the lower plate under the flywheel and see if the PTO input splines are stripped, OR the drive hub rivers are sheared.

you are referring to this bottom shaft correct? it does spin freely when i put a small strap wrench on it, and the motor does not spin. I took that bottom cover off under the flywheel. but it looks like there is another small round cover in there i’d have to take off in order to see the other end of that shaft, is that correct?

 

[Dieseltech]

you are referring to this bottom shaft correct? it does spin freely when i put a small strap wrench on it, and the motor does not spin. I took that bottom cover off under the flywheel. but it looks like there is another small round cover in there i’d have to take off in order to see the other end of that shaft, is that correct?

NO! Look UP at the clutch PRESSURE PLATE cover and see if the PTO INPUT splines are stripped in the hub, OR the hub to pressure plate rivets are sheared as does sometimes happen. I'd have a helper turn that rear transmission shaft while looking up inside. If that PTO input shaft DOES NOT turn then the trouble is INSIDE the transmission PTO drive gears.

 

[ford401]

NO! Look UP at the clutch PRESSURE PLATE cover and see if the PTO INPUT splines are stripped in the hub, OR the hub to pressure plate rivets are sheared as does sometimes happen. I'd have a helper turn that rear transmission shaft while looking up inside. If that PTO input shaft DOES NOT turn then the trouble is INSIDE the transmission PTO drive gears.

i’m sorry i’m not following exactly. when someone is spinning the shaft i showed in the previous photo I see nothing moving anywhere. It spins freely. while looking through the inspection hole from the underside of the clutch pressure plate, I’m not able to see any splines. i’ll attach 2 photos of what I can see through there from the bottom, one facing toward the back and one toward the front.

 

[Jim.ME]

i’m sorry i’m not following exactly. when someone is spinning the shaft i showed in the previous photo I see nothing moving anywhere. It spins freely. while looking through the inspection hole from the underside of the clutch pressure plate, I’m not able to see any splines. i’ll attach 2 photos of what I can see through there from the bottom, one facing toward the back and one toward the front.

The splines are in beyond the throw-out bearing, you may need a mirror or borescope. The throw-out bearing is on a fixed sleeve the shafts are inside that sleeve. PTO shaft is the one you will see, the transmission shaft is inside the PTO shaft.

 

[Dieseltech]

i’m sorry i’m not following exactly. when someone is spinning the shaft i showed in the previous photo I see nothing moving anywhere. It spins freely. while looking through the inspection hole from the underside of the clutch pressure plate, I’m not able to see any splines. i’ll attach 2 photos of what I can see through there from the bottom, one facing toward the back and one toward the front.

The PTO input spline shaft/hub is in FRONT of the release bearing. I'd back the release adjustment completely off and try to get that bearing far back AWAY from the release levers far as possible. Turn the flywheel a bit so you can see up BETWEEN the groups of pressure springs, then use a bright light and mirror to see the PTO drive hub in the pressure plate cover. I'll bet the SPLINES are bad. OR the hub rivets are sheared. If turning that REAR trans shaft does NOT turn the front drive shaft then there's internal gear damage at the FRONT of the transmission. E-mail is [email protected] if you want a cell number to call some evening.

 

[ford401]

The PTO input spline shaft/hub is in FRONT of the release bearing. I'd back the release adjustment completely off and try to get that bearing far back AWAY from the release levers far as possible. Turn the flywheel a bit so you can see up BETWEEN the groups of pressure springs, then use a bright light and mirror to see the PTO drive hub in the pressure plate cover. I'll bet the SPLINES are bad. OR the hub rivets are sheared. If turning that REAR trans shaft does NOT turn the front drive shaft then there's internal gear damage at the FRONT of the transmission. E-mail is [email protected] if you want a cell number to call some evening.

 

[Dieseltech]

Yup, I've seen that before...

 

[Jim.ME]

Yup, I've seen that before...

Kinda looks like a clutch, and likely shaft replacement, is in order.