How do you adjust the treadle peddle linkage on a Grand L40 series?

[Grateful11]

Years ago there was a thread on here on how to adjust the linkage or cables from the treadle peddle to the engine and transmission. The L3940 here has right at 3000 hours and the peddle has to be moved 10-15˚ before it even starts to move, in reverse it's as it should be. The engine revs but no forward movement until there's an excessive amount of peddle movement.

I've searched every which way I could think of to find that thread but couldn't. I need to either find that thread or could someone explain how to adjust it. We've looked but it doesn't just jump out at you.

 

[jonsstihl]

you don't have a cable for movement. the only cable is going to the injection pump for the auto throttle which you say works well. the 40 series is controlled by sensors in the pedal assembly.

what range are you in because I find mine takes more movement to move in H range than in M range. Although it may be more of a "seat of the pants" feeling

I would remove the floor mat and check for debris around the pedal assembly. there must be specs for the pedal sensor and ohms readings in the service manual. I can look them up later tonight. Also take a look at the bearings under the floor board as you move the pedal. they may need a little spray lubricant.

 

[Grateful11]

you don't have a cable for movement. the only cable is going to the injection pump for the auto throttle which you say works well. the 40 series is controlled by sensors in the pedal assembly.

what range are you in because I find mine takes more movement to move in H range than in M range. Although it may be more of a "seat of the pants" feeling

I would remove the floor mat and check for debris around the pedal assembly. there must be specs for the pedal sensor and ohms readings in the service manual. I can look them up later tonight. Also take a look at the bearings under the floor board as you move the pedal. they may need a little spray lubricant.

It's run in Medium range the majority of the time but on the road, if you can call it that, to the main hay shed it gets shifted into High sometimes depending on the road condition. I drove it today and in reverse it'll start moving before the engine even revs but definitely in Medium and High it's taking a good 15˚ or more of peddle to get it to start moving.

I'll look into this sensor assembly, probably have to blast out some mud and poop.

95% of this tractors job is feeding 2-3 round bales per day and in the last week it's loaded 56 loads of manure off the feedlot into a 155 bushel manure spreader.

 

[jonsstihl]

You may have to blast some poop off the underside to check the roller bearings but I think the sensor is on top of the floor board on the pedal assembly.

 

[jonsstihl]

sensor is on the pedal, resistance should move smoothly from 1K ohms to zero If you have a service manual it is in the electrical section page 9 s49

HST Pedal Sensor, Cruise Lever and Swashplate Position
Sensor
1. Measure the resistance between terminal B (7) and GND (8).
2. Measure the resistance between terminal GND (8) and a while
slowly turning the sensor shaft.
3. Measure the resistance terminal GND (8) and b (6) while slowly
turning the sensor shaft.
4. It is OK if the resistance value approximates to the value shown
in the table below.
NOTE
• When replacing the each sensor be sure to adjust the mode
"K".
(Reference)
• The change of resistance can be checking easily when an
analog tester is employed.
9Y1210369ELS0048US0

Reference
Terminal B – Terminal GND Approx. 1 kΩ

Terminal GND – Terminal a
Resistance is normal if
smoothly changing
Approx. 1 kΩ to 0 Ω

Terminal GND – Terminal b
Resistance is normal if
smoothly changing
Approx. 0 Ω to 1 kΩ

(1) HST Pedal Sensor
(2) Cruise Control Position Sensor
(3) Swashplate Position Sensor
(4) Sensor Shaft
(5) Terminal a
(6) Terminal b
(7) Terminal B
(8) Terminal GND

 

[jonsstihl]

that is the text from the manual and when you look at the sensor connector with the shaft that rotates facing down the pins are in order across the top 5, 6, 7, 8

hope the description helps. adobe free version doesn't let me do an extract of the page and save it as a file.

 

[jonsstihl]

if you do replace the sensor there is a "calibration" procedure

 

[jonsstihl]

from your description, sounds like the pedal's "zero" or Neutral is shifted. I would start with the roller bearings and linkage before removing sensors and maybe breaking delicate plastic things.

 

[jonsstihl]

one more thing to note is that the hst pedal, cruise control lever and the swashplate position sensor all appear to be the same sensor according to the service manual so you could probably swap the pedal sensor with the cruise sensor and see if the problem goes away.

 

[Grateful11]

from your description, sounds like the pedal's "zero" or Neutral is shifted. I would start with the roller bearings and linkage before removing sensors and maybe breaking delicate plastic things.

Thanks so much! Will definitely look at all the rollers and such. If it gets into electronics we'll probably have to get someone to to take a look at it.

I do have a WSM I downloaded but for some reason it has L3540, L4240, L5040, L5240, L5740 but omits the L3940 but I'm not sure how it could possibly be much difference.