873 locks up when moving

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slewpumper

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Mar 18, 2007
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59
Today was my first real work with my bobcat. Several diff. times when moving forward the bobcat would suddenly lock up and kill. This happened about 4 times today. I don't know if it is the seat sensor causing it or what. I am afraid to go very fast because when it locks it practically pitches me through the window. I have to hit the tracloc button to get unlocked. What is the cause of this, any ideas? I weigh about 160# and adjusted the seat so it wasn't so stiff thinking maybe my weight isn't enough to activate the switch. Any ideas what I can do? Can I bypass the seat sensor? Thanks for any advice. Other than that it worked great. I loaded 5 trailer loads of Oak and maple today to saw with my sawmill.
S5030093.jpg
 

skidsteer.ca

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Jan 20, 2006
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3,853
Does your machine have triangle headlights or rectangular head light. or what year is it?
Something is causing the park brake/pin to enguage, you need to solve this or remove the brake b4 you smash it uo with the sudden stops
Ken
 

Fishfiles

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Feb 8, 2007
Messages
1,698
From what you said about the seat sensor it makes me believe you have the first generation of the interlock system which had a seat sensor and the controller box was on the right side of the seat , there is a kit to eliminate the seat sensor from Bobcat , it was offered free for a while as an upgrade /warranty if you had a problem with the interlock , but that was probally 15 years past , it's pretty expensive , I seem to remember over $200 , but you can trick it by using a steel worm drive hose clamp, what you do is raise the cab and push down on the seat then wrap the clamp around the sensor so it stays engaged all the time , another way to do it is to remove the sensor from under the seat , clamp it together , tape it up and strap it out the way -, I have never figured out how to by pass it with the wires as it is a three wire , 6 volt set up -------when it locks up what lights are not lite on the interlock ? , there may be dirt or rocks under the seat , you could first try and wash it out with a hose , and also check the connection on the bottom of the controll box as corrision has a tendency to get into that plug
 

slewpumper

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Joined
Mar 18, 2007
Messages
59
From what you said about the seat sensor it makes me believe you have the first generation of the interlock system which had a seat sensor and the controller box was on the right side of the seat , there is a kit to eliminate the seat sensor from Bobcat , it was offered free for a while as an upgrade /warranty if you had a problem with the interlock , but that was probally 15 years past , it's pretty expensive , I seem to remember over $200 , but you can trick it by using a steel worm drive hose clamp, what you do is raise the cab and push down on the seat then wrap the clamp around the sensor so it stays engaged all the time , another way to do it is to remove the sensor from under the seat , clamp it together , tape it up and strap it out the way -, I have never figured out how to by pass it with the wires as it is a three wire , 6 volt set up -------when it locks up what lights are not lite on the interlock ? , there may be dirt or rocks under the seat , you could first try and wash it out with a hose , and also check the connection on the bottom of the controll box as corrision has a tendency to get into that plug
Thanks for the replies. My skidloader is a 1995 873. It does have the control on the ride side of the operator seat. Thanks!
 

nobull1

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Joined
Jan 4, 2007
Messages
196
Thanks for the replies. My skidloader is a 1995 873. It does have the control on the ride side of the operator seat. Thanks!
Fishfiles

When you say clamp the seat sensor. Do you mean to put the clamp around the plunger while it is depressed, while holding the seat down, to hold it in place? Is the clamp strong enough to hold the seat spring down and not damage the plunger?
 

Fishfiles

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Feb 8, 2007
Messages
1,698
Fishfiles

When you say clamp the seat sensor. Do you mean to put the clamp around the plunger while it is depressed, while holding the seat down, to hold it in place? Is the clamp strong enough to hold the seat spring down and not damage the plunger?
Yes the clamp will hold the white plunger in the postion so that the magnet will activate , the spring force is very minimal , it almost takes two people to do it on the machine as you have to push down on the seat with the cab open while you postion and tighten the clamp , like I mentioned it is a little easier to take the sensor off the bottom of the cab , clamp it then tape and strap it up out the way ------the kit they sell has a new controller box , push to operate switch and a new operator manuel that straps behind the seat , it cost around $200 US and takes about 20 minutes to install --------a slim jim like they use to open lock doors on cars and a garden hose will sometimes clear any dirt from under the seat plate which is usually the problem of way the seat sensor doesn't activate , and thats no bull , fishfiles
 

skidboy

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Joined
Jan 3, 2007
Messages
94
Yes the clamp will hold the white plunger in the postion so that the magnet will activate , the spring force is very minimal , it almost takes two people to do it on the machine as you have to push down on the seat with the cab open while you postion and tighten the clamp , like I mentioned it is a little easier to take the sensor off the bottom of the cab , clamp it then tape and strap it up out the way ------the kit they sell has a new controller box , push to operate switch and a new operator manuel that straps behind the seat , it cost around $200 US and takes about 20 minutes to install --------a slim jim like they use to open lock doors on cars and a garden hose will sometimes clear any dirt from under the seat plate which is usually the problem of way the seat sensor doesn't activate , and thats no bull , fishfiles
I doubt that the seat sensor is the problem,as when the system is operational (you are sitting on the seat with the seat bar down ) you can lift of the seat and it will not lock up.I would be looking at a worn bush in the seat bar sensor on the left side of the seat bar.
 

slewpumper

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Mar 18, 2007
Messages
59
I doubt that the seat sensor is the problem,as when the system is operational (you are sitting on the seat with the seat bar down ) you can lift of the seat and it will not lock up.I would be looking at a worn bush in the seat bar sensor on the left side of the seat bar.
I ran it most of the day yesterday without a problem. When it does act up it seems to be when I first start running it. After it warms up it doesn't seem to bother. Thanks all for the replies.
 

slewpumper

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Joined
Mar 18, 2007
Messages
59
I ran it most of the day yesterday without a problem. When it does act up it seems to be when I first start running it. After it warms up it doesn't seem to bother. Thanks all for the replies.
Here is a link to a picture of my skidloader loading logs for the sawmill. May have to copy and paste url into address bar. http://i129.photobucket.com/albums/p213/slewpumper/S5030093.jpg
 
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