Slowing up the BX - HST pedal sticking revisited.

[Roy]

Yes, I said slowing up.

I have had the old HST pedal sticking problem again, all winter long. It reached the point where I was hitting the linkage with WD40, moly or lithium sprays after every use, each proving to be temporary solutions. And no, it hasn't been washed since June or July.

So, today I finally had some time to check it out. Lubricated the linkage again, no fix. Tightened the return spring, a lot. It still stuck most of the time whenever I held the pedal to the full-speed position, for about 30 seconds or more. Then I noticed that it would never stick (after about 20 test iterations) when I limited it to approximately 1/16 to 1/8 of an inch above the petal-to-the-metal position. So, I raised the speed-limiter (the bolt controlling the maximum forward movement of the pedal). Took it through the paces, problem seems to be resolved.

First, let me state that a slightly slower BX doesn't really bother me. Since my turf is not that well graded, full throttle has always caused some discomforting bounce. Secondly, there is the issue of my sons. When they drive the tractor, I feel more comfortable with a lower speed. (And I absolutely feel a lot more comfortable, with any of us behind the wheel, believing that the pedal WILL return to the neutral position).

Now, sometime in the immediate future, when I can give the tractor up (calling for snow tomorrow night, so now is not the time), I plan to return the limiting bolt and spring to their original positions, and have the dealer look at it (I still have 11 months on the warranty).

In the meantime, what I am interested in finding out; have other BX owners who have had the problem find that the pedal is sticking more and more? If so, there may be a possibility that the return spring is losing force over time.

 

[paccorti]

Does your pedal seem worse when the hydro fluid is cold? My TC35 sticks (or returns more slowly) when cold. After a little warm up it is all fine.

Peter

 

[Anonymous Poster]

I was experiencing the same problem on my BX and by disconnecting the linkage from the pedel under the tractor realized that the pedel pivot was the culprit for the sticking. Mine was quite tight and the plan was to just remove it and clean up the shaft and bushing, relube it with some grease and problem solved. Hmmm.. not so easy though, in order to get the pedel off the pivot shaft the floor and fender assembly has to be removed. This is quite a big job. So the next best thing I could come up with was to remove the retaining clip and slide it off as far as possible, it will move about half the distance it is on the shaft before it hits the floorpan. I really had to work at mine as the shaft was quite rusty already. It was apparent that no lubricant of any kind was used on assembly. I used some sanding cloth to polish the exposed portion of the shaft and applied some penetrating oil to work the rest loose. after working the pedel back and forth and applying oil a few times I had it flopping around freely. Now to prevent further trouble I wanted do something that would be easier to address in the future so I decided to do what Kubota should have done from the start and install a grease fitting. The way I achieved this was to drill the center of the end of the pedel pivot shaft to a depth that matched the exposed portion of the shaft with the pedel slid off the shaft as far right as it will go up against the floorpan. Use a drill just under 1/4" so the hole can be tapped to 1/4NF28 so a small grease fitting can be threaded in. then using a 1/8" drill I drilled a hole perpendicular to the shaft as close to the center as possible halfway through so it would intersect with the other hole in the center of the shaft. (you will have to unbolt the pedel from the pivot block to get enough clearance to do this) Blow the holes clean to remove all metal chips and reassemble everything and install a zerk fitting. Now I can grease the pivot and doubt this will ever be a concern again. I also decided to try leaving off the small dampening shock on the linkage and I can't see any reason why it was needed. I have no problem moving the pedel smoothly now with no jerking.

 

[Anonymous Poster]

Reminds me of the 3pt balls on my BX, no lube and as tight as a pinched chain saw.

 

[Roy]

Stephen; I had the same thought about zirc fittings. If your problem stays resolved, I may do the same operation. I revisited the linkage after I posted, and I also suspect that the damping shock maybe a major culprit. When this subject was pursued last September ("Sticking HST Foot Control"), watersjj noted that he too removed the shock. If I have the time this weekend, I may do the same. Question: Without the damper, do you find the pedal returns too quickly?

 

[Pks]

Just a thought,

The service manual for a B2400 HSD states that the velocity damper (shock) was added in order to eliminate the possability of sudden stops when the foot is removed from the drive pedal. The sudden stop, says the manual, may send a shock wave into the drive systems and over time could damage the internal workings.

The fluid in my shock absorber blew itself all over the frame this past December. So now the tractor can stop so fast that the fillings in my molars feel like they might come loose. But there is one advantage-on ice. I can use this new "insta-stop" feature to spin the tractor about 90 degrees when I'm turning while in reverse. All I do is start my turn while backing up at high speed throw the wheel to one side (left) then take my foot off the pedal. And presto, the tractor slides the front wheels over the ice while the rear wheels stop rotating and allow the whole thing to pivot on a dime. Not recommended for your everyday work habits. I've only done it twice-but it is kinda fun.

I'll be getting a new shock soon.

Peter

 

[DaveNH]

PKS,

Try loading up the FEL and seeing if it would spin 180

We're all in this together! (3)

 

[Roy]

The BX's particular sticking is temperature (ambient and environmental) independent. When it sticks, it always sticks (is not a come-and-go situation).

 

[Anonymous Poster]

No Roy I don't find any trouble with the pedal returning too soon. With the BX pedal design your foot stays in contact with the pedal all the time so it rarely has the chance to return under it's own freedom. And besides if an emergency stop was needed, having the pedal return slow is the last thing you would want. The bigger HST Kubotas have a clutch pedal which could be used in and emergency quick reaction stop but with the BX you're relying entirely on the HST mechinism for control.

One more thing I forgot to note: If the damper shock is removed, a couple of close fitting 5/16" flat washers should be placed on the control rod on either side of the eye hole in place of it on the pedal pivot block to keep the rod centered and take up some of the gap left by the loss of the shock eye, just to help keep things lined up.

 

[watersjj]

I still do not have the shock absorber hooked up to my HST control. To avoid sudden stops, I took some tension off the return spring as mentioned in original post. I've had no problems since removing shock. My previous HST tractor with foot control did not have a shock absorber at all and gave no problems for the 10 years I owned the tractor.