MF178 Hydraulic noise

[depratt_equip]

Got a massey MF178 (same as MF175) in the shop other day. has a loud knock from the tranny. Pulled the top cover and didn't see anything that jumped out at us. Sound seems to be coming from the pump in the middle of the tractor. Anyone ever messed with one of these or had any Hydraulic pump problems. Any ideas would be great....

 

[JerryG]

Does the lift work at all?

 

[depratt_equip]

Ya it works.... Knocks hard under load.... with no load it still knocks but not as bad...

 

[JerryG]

It's been a long time since I worked on them. I just wonder if one of the brass blocks is cracked. E-mail Big Dean, he will be able to tell you right off.

 

[spb1971]

Sounds like you are running it all the way up in "Constant Pump". If you do that, the system "dead heads" and will knock. Do you notice it when your lift control handle is in the mid-point area?

 

[JerryG]

<font color="blue"> Sounds like you are running it all the way up in "Constant Pump". </font>
Given his experience I didn't mention that. But, after thinking about it, the adjustment could be off to where it is going into constant before the height that it should.

 

[depratt_equip]

do notice it when the lift handle is in mid or lowered all the way.. one of the blocks seems to have a lot of play in it.

 

[JerryG]

Sounds like you may have to take it apart.

 

[CMunger]

A 178, built in England, is not the same as a 175, built in the US. They have alot of the same componets, but are not the same. Different steering, different clutch, different hood, that's about it. The US engineers were free to design the changes they felt they needed for the US.
Chuck

 

[Farmwithjunk]

</font><font color="blue" class="small">( Sounds like you are running it all the way up in "Constant Pump". If you do that, the system "dead heads" and will knock. Do you notice it when your lift control handle is in the mid-point area? )</font>

My 150 MF has done that since new (1971) It's got a bit louder over the years, but never been a problem.

As mentioned, just move "position control" lever down a half inch or so. See if that quiets the noise.

I was told (by mechanic at MF dealer) that's noise from pressure bypass unloading when in constant pumping position.

 

[depratt_equip]

CMunger - guess i should have said very close to a 175

Farmwithjunk - only thing is it still knocks with the lever all the way down.

We split it in two... very easy job.. seems to be alot of slope in cam blocks and pistons... ordered a rebuild kit and will see if that helps...

 

[depratt_equip]

Just wanted to post an update... We finally found the source of the knock. It was not the pump like we though but the like (6" diameter gear) in the main transmission that drives the pump... It was short 2 teeth and letting it bang back and forth... /forums/images/graemlins/shocked.gif gear ran about $300