Hydro ?

[608KEB 795]

I have a 1974 B-100. The Hydro doesn't run smooth. It's jerky when I increase my speed. It is more jerky in reverse. The speed is constant though. I have used wd40 on the lever components. I soaked it a couple of times a day for about a week. My C-120 and 520H does the same thing. looking for ideas on how to fix this. I have another B-100 that operates smooth as I increase or decrease speed.

[Jeff-C175 7,203]

If you are sure that it's something in the linkage and not the tranny itself, then I would suggest 'losing' the WD40... it's really not much of a lubricant and it evaporates sorta quickly.  Maybe try a silicone based lubricant?

[daveoman1966 3,762]

BIG MISTAKE...  The motion control components are designed to work dry...don't oil or WD-40 those components.  The 'constant speed' concept is in maintaining firm and precise positioning of valves inside the hyd pump.  The only way to set and hold precise positioning of these valves is thru resistance of friction surfaces in the control lever(s).  When you oil the components, you are defeating the purpose of the friction controls...that being counter-productive.  As a 2nd reason for dry operation...oil collects dust and dirt and holds it like glue. 

Don't use oil or silicon or any other sort of lube.  In fact, if you have done so, you'll now have to take it all apart to clean off all the oil residues you have introduced.  That oil you so meticulously and thoroughly applied is quite likely the culprit here.

In addition to that, particularly the C-120 & B-100 ...  Inspect the nylon cam and eccentric cam follower.  The nylon cam MAY be broken or cracked.  The cam should NOT be sloppy in its motion up / down.  Also look at the ledt side of the hoodstand where the friction collar shaft is bolted to the hoodstand....is that tab cracked or broken, which would allow the friction collar to move at will.   You should also look under the tractor and inspect the frame plate where it is bolted to the trans (4 bolts).  This plate is often cracked which allows for an increasingly worse 'flex' in the motion controls.  I have seen where this is so bad that the cam follower has been crushed.       

Edited September 3, 2013 by daveoman1966

[608KEB 795]

No cracks on the frame. It had a couple of spider cracks that I welded up last fall. I removed the transmission, so I could weld it from the backside. The bolt that holds the hydrostatic assembly in place was a little loose. I tightened it up. It seems better now. All three tractors jerk a little as you apply pressure to the handle in forward or reverse. It's not horrible. I was just wondering if this was common. I have applied no lube to the C-120 or 520H.

Edited September 3, 2013 by 608KEB

[daveoman1966 3,762]

I suppose the degree of jerking is relative to the user....   I don't notice it so mcuch with my C-160 or Bronco14.  I do, however, notice it markedly when its my wife doin' the jerking.

[Trouty56 567]

I suppose the degree of jerking is relative to the user....   I don't notice it so mcuch with my C-160 or Bronco14.  I do, however, notice it markedly when its my wife doin' the jerking.

 

Not sure if I should be sympathetic or jealous....

[608KEB 795]

I should've known better.    

[KATO 115]

:laughing-rolling:

[546cowboy 301]

I have always used white lithium spray on every one I have ever had and they have all worked great.

[Jeff-C175 7,203]

Me too Lynn.  every couple years I'll open her up, blow and wipe any dirt (usually not much), shoot em all up with whit lith and good to go.  Haven't had any problem with the linkage in 20+ years.