Massey 35 "Piston Slap" hydralic pump on lift with engine idling

[bmccartney]

I have a Massey 35 deluxe that I recently purchased as our first tractor. I don't have a lot of seat time but when I was moving a heavy 6 ft brush hog I heard what I can only describe as piston slap with lift at idle. I also have a 5 ft land pride tiller that is pretty heavy, too, but doesn't hang so far off the back of the tractor that I haven't noticed the sound with. It sounds like the pump is knocking or something when I raise the mower off the ground and the tractor is idling. I believe the sound goes away at higher RPM but being a 3 cyl diesel is awful noisy so it is hard to tell for certain. Fluid level is at the full mark. Is the mower too heavy? Does it have to do with low pressure because the pump is at idle? Should I be concerned or take it to a shop or is this normal? Thanks!

 

[pjbci]

Are you by any chance moving the lever past the top stop and into the "constant pumping" position. That tiller isnt heavy enough to make your pump knock like that. I know the sound you describe. I have heard it before with very heavy loads that raise the tractor front off ground or when the lever get accidentaly moved past the upper stop.

 

[bmccartney]

With the mower on it knocks even at half way up. If I take off in 1st high it will pull the wheels off the ground if the back mower wheel is off the ground.

 

[pjbci]

That may be normal then. Im not sure but both my 135 and TO35 do the same when the load is heavy enough to lift the front.

 

[Farmerford]

I think it must be a built in feature. I recall the same knock on a brand new MF 35 diesel we bought for the farm in 1960. I worried about it; my father called me an "old maid" about machinery noise; and it knocked exactly the same, not more or less, until we sold it with 8,000 hours on it.