PTO Problems

john2459 · Apr 27, 2012

Good morning all,
I have a Massey Ferguson Super 90 WR and I知 having a problem with the PTO. If the lever is in the ground position it works, neutral works as well. However, when the lever is in the engine position it does not work. I brought up the RPMs a bit and it seemed to move slightly but nothing substantial. This is the model with the Multi-Power and I think that has an interaction with the PTO but I知 not an expert by any means. I recently replaced the hydraulic pump so the hydraulics work and if I知 not mistaken the hydraulics play an integral part in the PTO. I致e resigned myself to the fact that I will probably have to split the tractor AGAIN and the problem will lie in the most remote part thereto. If anyone has any ideas please let me know. I appreciate any help in advance and thank you for taking the time to read this.
John B

Dieseltech · Apr 27, 2012

MF S90 used return oil from power steering pump to operate PTO system on both 8 speed and MP models, also needed to operate both hi and lo MP clutch pack. Three point pump only takes care of auxiliary valves and three point if equiped, has nothing at all to do with PS system. Does power steering work OK, does both hi and lo MP clutch work OK? If not PS pump may just need inlet screen cleaned, is bolted to cast iron plate at front of trans on right side ahead of brake pedals. Can be removed after 5 gallons of oil is drained from front trans drain plug. Try to save gasket as it is no longer available, may also need new O ring in upper corner. New pump is still available but expensive. When my 85D starts steering hard I clean the screen and it will work again. Have a S90 diesel puller but both pumps are stripped out along with other uneeded parts to get it down to 4500 lbs, pumps were both bad anyway. If you like call 574 893 4172 after 7 PM, can talk faster than I can type.

john2459 · Apr 30, 2012

Thanks for the quick reply Dieseltech,
To answer your questions, Yes the PS works great although I have a moderate leak under the PS unit in the front that I can稚 see but she always 杜arks her spot when I shut her down. As far as the Hi Low clutch working I can稚 really say for sure. In Penrose CO we don稚 have any hills to check it with but I really don稚 notice anything different when I step on the clutch. I understand that if you step halfway on the clutch it is supposed to disengage the PTO and if you step on it fully it disengages the engine. If I知 incorrect in that let me know, but all in all I can tell or feel nothing different. I値l try to give you a call early this week as my typing skills are in the same boat.
Thanks
John B

Dieseltech said:
MF S90 used return oil from power steering pump to operate PTO system on both 8 speed and MP models, also needed to operate both hi and lo MP clutch pack. Three point pump only takes care of auxiliary valves and three point if equiped, has nothing at all to do with PS system. Does power steering work OK, does both hi and lo MP clutch work OK? If not PS pump may just need inlet screen cleaned, is bolted to cast iron plate at front of trans on right side ahead of brake pedals. Can be removed after 5 gallons of oil is drained from front trans drain plug. Try to save gasket as it is no longer available, may also need new O ring in upper corner. New pump is still available but expensive. When my 85D starts steering hard I clean the screen and it will work again. Have a S90 diesel puller but both pumps are stripped out along with other uneeded parts to get it down to 4500 lbs, pumps were both bad anyway. If you like call 574 893 4172 after 7 PM, can talk faster than I can type.

banjodunn · Apr 30, 2012

john2459 said:
Thanks for the quick reply Dieseltech,
To answer your questions, Yes the PS works great although I have a moderate leak under the PS unit in the front that I canç¨š see but she always æ�œarks her spot when I shut her down. As far as the Hi Low clutch working I canç¨š really say for sure. In Penrose CO we donç¨š have any hills to check it with but I really donç¨š notice anything different when I step on the clutch. I understand that if you step halfway on the clutch it is supposed to disengage the PTO and if you step on it fully it disengages the engine. If IçŸ¥ incorrect in that let me know, but all in all I can tell or feel nothing different.

G'day I think you are correct with that and you are supposed to have a two stage clutch, I don't think your model has a hyd clutch in the pto.
I think you may have a bad clutch which means splitting the tractor

Jon

Dieseltech · Apr 30, 2012

You have foot clutch backwards, push about halfway to shift transmission or stop forward/ reverse travel, push clear down stops trans AND dumps oil pressure to hydraulic PTO clutch pack. Originally a red light came on when PTO pressure dropped below 120 PSI when pedal was fully depressed by dump valve in trans input shaft cover assy. Be glad to talk when you can, am on Eastern time in IN, I think 2 hours time diff.

banjodunn · May 1, 2012

I think I need to read things when I have had my 1st coffee for the day

you are spot on dieseltech about the two stage operation i'm sorry if I gave you a bum steer

Jon

Dieseltech · May 1, 2012

Hi Jon, I use Mtn Dew instead of Coffee for my daily jolt, lots to see on this site, no harm, no foul done.

john2459 · May 1, 2012

Good morning all,
I think I may have a hyd pto clutch as when I had it split to replace the hyd pump (remotes) there was a line that seemed to back to the PTO. However, I may be mistaken. I DO however, have a red light and of course it doesn稚 work, for the PTO. As all this filters out I have this sinking feeling that I will be back in this thing again soon? I値l however, try to clean the screen or R&R the 徹 ring. You never know! BTW I appreciate all the great help with this.
John B

Dieseltech · May 1, 2012

You are right about small oil line, it supplies oil to PTO shift valve from transmission input cover assy. 85, 88 and S90 all had the same system for PTO operation. Now if you REALLY want a strong PTO clutch, drill 3 bolt holes through whole assembly like I did on my S90 diesel puller, bolt everything solid for dyno testing. This was done while everything uneeded was stripped out to get under 4500 LBS for pulling. Of course you won't be able to shift it anymore, but will hold over 200 HP now while testing turbo boost on engine. Would rather play with tractors than play cowpasture pool!

mschreiner · Mar 18, 2014

Dieseltech,
You sound very knowledgeable with the super 90’s and multipower.
Wonder if you can help. If you prefer not to, I understand as you probably get contacted quite often.
I have had this issue and it is driving me crazy.
I cannot maintain pressure above 100psi (not the 225 as recommended) and everything else works great, so therefore, PTO is worthless under load.
I have replaced the regulator spring, made sure of no regulator spool binding, bored out the housing as per the shop manual so spring does not bind,
Changed every O-ring, seal, shaft seal, bearing, etc. possible, have 1500psi at power steering (works great), hoses are fine, shifting is not simple unless hi-low selected prior to gear selection and sometimes need lower engine speed. I feel that I have covered every base possible as I have split many dry tractors in the past and fixed them quite easily. This one is quite tricky though, being a wet system, but not too challenging to understand. I have torn it apart many times to double and triple check any dumb, human mistakes and still found no errors. When I put it back together, still holds at 100psi measured in the return line. I have not tested at the hi-low ports thru the inspection plate. I split it again last night and pulled the mulipower off. I will take this apart again to see if I have a seal, clutch, or something that has failed.
Would you have any ideas????
Thanks,