743 Sticks Self Enguage

[tlaff]

I have a 1987 743 and the left and right steer sticks self enguage and move the machine forward on it's own. I have checked the adjustment on the pump and it seems to be right. I set the park brake and it will not move forward but it seems the the motor bogs down and makes a metal rattle sound and when cold the sticks will move forward and actually kill the motor. Any help would be greatly appreciated.

 

[fairmountvewe]

Way out in left field here, but are the control linkages free to move when the machine is shut down? From the comment about the motor bogging down, it sounds like the control arms are not returning to neutral (the is a spring that takes care of that right behind the bulkhead) and are constantly loading the pump? Your comment about the linkage being properly adjusted not withstanding, do you have travel on both sides of neutral? Then you go through the simple stuff, did this just happen recently? Is it a new to you machine?, has there been maintenance done to it recently?, are all the levels correct?. Sorry I can't be more help. Peter

 

[Tazza]

Way out in left field here, but are the control linkages free to move when the machine is shut down? From the comment about the motor bogging down, it sounds like the control arms are not returning to neutral (the is a spring that takes care of that right behind the bulkhead) and are constantly loading the pump? Your comment about the linkage being properly adjusted not withstanding, do you have travel on both sides of neutral? Then you go through the simple stuff, did this just happen recently? Is it a new to you machine?, has there been maintenance done to it recently?, are all the levels correct?. Sorry I can't be more help. Peter

Also check your spring, it should hold the sticks in neutral. If the adjustment is slightly out, it will try to force the sticks forward and you will hear the whine or grinding sound from the pump. It will easily kill the engine if the brake is on and they fly forward. It really loads the engine down so much that it will stall. The round oucks on the pump should be flat against the stops, the stops shouldn't have any worn patches, they should be flat.

 

[tlaff]

Also check your spring, it should hold the sticks in neutral. If the adjustment is slightly out, it will try to force the sticks forward and you will hear the whine or grinding sound from the pump. It will easily kill the engine if the brake is on and they fly forward. It really loads the engine down so much that it will stall. The round oucks on the pump should be flat against the stops, the stops shouldn't have any worn patches, they should be flat.

This machine has over 5000 hours of hard use. The sticks have full range in both direction. The steering linkages have alot of wear at the bushings and I did notice that the spring adjuster is all the way to the shoulder of the bolt. Maybe I'll try a few washers as a spacer on the spring until I can rebush the entire linkage system. It seems that there is very little play between forward and reverse on the sticks as well. I have not worked (as a mechanic) on Bobcats at all although I have 30 plus years of operating them. Thanks for all of your help.

 

[tlaff]

This machine has over 5000 hours of hard use. The sticks have full range in both direction. The steering linkages have alot of wear at the bushings and I did notice that the spring adjuster is all the way to the shoulder of the bolt. Maybe I'll try a few washers as a spacer on the spring until I can rebush the entire linkage system. It seems that there is very little play between forward and reverse on the sticks as well. I have not worked (as a mechanic) on Bobcats at all although I have 30 plus years of operating them. Thanks for all of your help.

This thing is starting to drive me nuts. I don't think I made a very good choice purchasing and old machine. Now when I tried to start the thing in cold weather (low 30's) the machine started to move forward on it's own and the lift arms began to move the bucket up on it's own. I'm going to kill myself on this thing if I don't get it figued out. Any suggestions??

 

[busa4]

This thing is starting to drive me nuts. I don't think I made a very good choice purchasing and old machine. Now when I tried to start the thing in cold weather (low 30's) the machine started to move forward on it's own and the lift arms began to move the bucket up on it's own. I'm going to kill myself on this thing if I don't get it figued out. Any suggestions??

check to make sure the machine is not stuck in or partially engauged in auxilary(right side stick control left and right movement). it makes the hydraulics do weird shit.
i too have the same machine and let me tell you it kicked my ass. i just purchased the 4 steering linkage bushings from bobcat and they were cheap. replace the bushings and start over with the steering linkage adjustment.

 

[Tazza]

check to make sure the machine is not stuck in or partially engauged in auxilary(right side stick control left and right movement). it makes the hydraulics do weird shit.
i too have the same machine and let me tell you it kicked my ass. i just purchased the 4 steering linkage bushings from bobcat and they were cheap. replace the bushings and start over with the steering linkage adjustment.

Creeping isn't a big deal, but the lifting on its own is an issue...
How tight are your foot pedal linkages? if they are too tight, they may be out of alignment when you start up causing it to lift on its own.

 

[tlaff]

Creeping isn't a big deal, but the lifting on its own is an issue...
How tight are your foot pedal linkages? if they are too tight, they may be out of alignment when you start up causing it to lift on its own.

The foot pedals seem to be fine and work correctly when the machine is working. The bucket lift issue has only happened once and it was while the starter was engaged attempting to start the motor. The Bobcat began creeping when starter is engaged about 15 running hours ago as well. Thanks for all of your help.