ih 574 pto question

I just bought this old 1975 574 diesel and the power steering and brakes are not working,does the loader,pto andlift arms work off the same hydraulic pump?now the pto quit working,what does the transfer pump work?thanks Joe

Hi Joe, there is only one hydraulic pump on 574,
the MCV valve flow diver splits the hydraulic
feeds:
9 GPM to 3pt, remotes and loader.
3 GPM to PS, PB, PTO, Oil cooler and transmission
lube.

The transfer pump, pumps hydraulic fluid between
compartments in the transmissions and differential
and supplies lube to transmission.

Sometimes PTO problems are caused by a sticky
actuator mechanism. It is valve under the rubber
boot on top right of MCV valve. Lift boot and
spray your favorite lubricant on the valve and
mechanism while engaging/disengaging the PTO
lever.

JimB

thanks for the reply,I have removed all valves from the mcv and did not see anything broke.I have also removed the hydraulic pump and the mcv,the pto actuator is working in its bore i checked that,I bought a I&T book from tractor supply for my model but it does not go into great detail.The pto was working when I got it,its not working now,I checked the power steering pressure side on the mcv and it was 150psi my book did not disclose what the pressure should be.thought about buying all new valves for the mcv,just don't want to throw away bad money.

thanks again
Joe

Joe, with engine at 2300 RPM, 684 I&T says PS should
trip relief valve at 1500-1600 PSI and flow should
be 2.5 GPM. PTO pressure should be 230-250 PSI.

JimB

Jim

I did some testing today, ran a flow test on the hitch pressure side and at full throttle it flowed 12gpm open flow,on my meter I can't restrict it,moved it to the steering pressure side and no flow found,ran a hose from the hitch pressure side to the steering line and the powersteering is working, so that leads me to believe the flow divider in the mcv is bad,but I remove it and look at it and don't see anything wrong with it and it's not getting stuck.I think some body has been in it before but looking at the case website, looks like all parts are there. Just wanting your opinion. thanks

Hi Joe, from your tests it would appear pump is functioning well and PS will work if it has an oil supply. Unfortunately I have never had an MCV apart but it is not a rocket engine so I believe we can figure this thing out.
Since you had MCV off the tractor, were the gasket and O-Rings between the MCV and pump all good?
Some questions:
1)Are the hydraulic oil flow channels in the MCV casting or is the function performed by the gasket and plate between MCV and pump?
2)Did you blow out all the oil flow channels with compressed air?
3)Is it possible the problem is PS relief valve (parts book items 6,7,8,9) is stuck open allowing the oil flow to bypass the PS outlet, items 10 thru 14.
4)Item 12 PS check valve, could it have been installed backwards so no flow to PS? I believe its function is to prevent PS from loosing prime.

Just some thoughts and questions, I like a good mystery.

JimB

Jim
gaskets and orings were good,the flow channels are in the casting and looked good and clean,blew out everything with air,I thought the same about the ps relief valve,when I had the mcv off I took it apart and made sure the spring was not broken and the poppet was seating good inside of the valve.then i thought well even if it is stuck open then it should have flow right?the ps check valve, i checked it and and tried to install it another way and it would only go one way,the elbow fitting for the ps return line at the mcv has the check ball in it,I'm gueesing to allow fluid to return to the mcv but once the engine is cut off it won't allow it to return and bleed off like you said.I'm wondering if the pump is weak and pumps good free flow, but the book is saying it should pump 12gpm restricted to 1200 or 1600psi.and my meter doesn't allow me to restrict.I would think that steering and braking would take priority over hydraulics so the flow divider would work the steering and braking if pressure was to low.but I haven't messed with tractors to much.The other thing is the pto was working good,hooked it to a shredder and it turned it no problem.now its not working but it did when i had the hitch pressure hooked to the steering line but it felt weak as it would turn but I could hold it with my hand.I know it has me scratching my head

thanks Joe

Joe, does the flow divider have a neoprene seal on
the top of the spring? Does it work by sealing a
hole in the casting bore?
Yes first priority is to PS, PB and PTO.
I believe the way the flow divider valve works is
that it covers or seals a hole in the top of the
bore until the hydraulic flow exceeds 3 gpm and
then it opens to allow the excess flow to the 3pt
system.

So everything still points to flow divider being
open allowing all flow to 3pt.

JimB

there is no neoprene washer on the spring,is there suppose to be,i don't know about the bore being closed off because some of the ports you cannot see, they are internal,I'm wondering if the pto pressure regulating valve is set at too high of pressure.I noticed someone has installed a small lockwasher on top of the shims I guess to bring up the pressure,maybe it's to much pressure causing the flow divider to bottom out causing all fluid to 3pt.this is getting frustrating,I would take it to a dealership to get fixed but I know how they operate,I might have to take my chances,btw I seen on messiks website case is proud of their product,like over $200 for the steering relief valve and over $300 for system relief valve.

Joe

Joe, I don't know what the spring is suppose to press against. There has to be something that closes off a hole in the bore somewhere.
Bernard le Mechano said once to put a clean bucket under the MCV, take the flow divider plug and spring out, start the tractor and pull on the remote hydraulic lever and the flow diver valve will be forced out into the bucket. I don't know if this only applies to the newer designed MCVs or the older version like your 574.

JimB

Jim
do you know where I could buy a good used mcv valve assembly?

Hi Joe, I live in eastern Canada and the best one
that I know of in eastern Canada is:
http://www.fawcett.cc/Salvage/salvage-home.htm

They have several 74 series tractors. I have no
affiliation with them.
You probably live in USA, so shipping costs would
be less from a salvage yard near you. About a year
ago someone posted a list of salvage yards on the
this site.

I still believe the spring in the flow divider
valve has to push on a sleeve or ball to close a
hole in the bore to divert the fluid to the PS,PB
& PTO.

Good luck
Jim

thanks for the info we will see what I find thanks

Jim

got the problems fixed,replaced the mcv valve assembly,all I have to do now is bleed the brakes.

Thanks Joe