knocking sound below hi/low gears

[smtbbc]

Hello, I've posted a couple times here with great results...so need help/advice on problem...



Tractor mf 135 ad3 diesel. Today while turning some ground over I bogged down and lifted the arms a bit.. a knocking sound began below the gear shifters. it still was shifting gears and working.. when I speed up or throttle up it increased the knocking to a more rapid pace. I raised the arms and went to park it and the knocking went away.. it was severe enough to startle me.. and stop working..

 

[DJ54]

Could be one of the dowel pins that hold the lift pump in place is worn, or has broken. From the outside, you'll see the small diamond shaped dowel pin cap, with a couple of bolts in it. If you have a shop manual, it should show it.

A pretty common occurrence with the Massey's.

 

[banjodunn]

G'day sounds like you have moved the control lever into constant pumping and the knocking you can hear is the relief valve going off


Jon

 

[timberjackrob]

every old massey we ever had made a knocking sound if the lift arms were raised all the way to the top

 

[JWR]

every old massey we ever had made a knocking sound if the lift arms were raised all the way to the top

Yes, tmberjackrob is right. With the Massey system, if you have the lift control high enough to trigger "constant pumping" as banjodunn mentions, it can go into an horrendous clanking in the bowels of the chassis BUT NOT ALWAYS. You have to have it just right to get it into oscillation. I have a 2011 MF2660 (bought new.) Under certain circumstances with the control lever up close to the constant pumping point the clanking sometimes got loud enough to scare you right off the machine ! Incredible. About like 2 main bearings had gone at the same time... I've had MANY old MF owners and dealers tell me it is common place with MF for decades. The best explanation I heard is this: First, the lift pump is concentric with a splined shaft leading to the PTO. There is a pin (as DJ54 mentions above) that goes thru the lift pump to hold it and prevent rotation. That rod has a tiny amount of play in the attachment to the pump as well as in the surrounding heavy chassis where it is seated. If you get just the right amount of "slop" in the load on the lift pump it will "rattle" or oscillate on the rod that keeps it from rotating. Can be LOUD! You should be able to make it quit by bringing the control lever down a little(forward) away from the "constant pumping" point. I had an old diesel mechanic hear it one time and he literally came running at me as hard as he could go yelling "shut it off, shut it off!!" Mine did this with less than 100 hrs on it. So I personally do not think it is wear-related, though no doubt it may get worse with age. Not to worry. The thing is OK.