I have a Bobcat 763, guessing early 90's, that is getting a traction lock hold circuit shorted to ground flash code (Traction LED blinks 3 times on the BICS). The failure happens when I have middle to upper RPMs, but not so much with just idling around. I don't have a service manual so I am at a lose as to how to go about trouble shooting this failure. I don't know what wire(s) are associated with the traction lock hold solenoid that go to the BICS but I did look at the wire harness in general and didn't see any wires that I suspected were shorting. I am not sure what solenoid is associated with the traction lock hold circuit.... thus I haven't verified it. Thanks in advance for any assistance you may be able to give. Regards, Dave
I should add a little more detail. The traction lock works initially and I am able to drive the machine. When I increase the RPMs the machine will lock while driving, almost throwing me out, and then the flash LED of 3 shows up. At that point I shut the machine down,restart it and the failure clears until the next time.
The traction lock circuit has a fuse, a relay, the brake solenoid, the Traction Lock Override button (if equipped), the brake switch on the floor and the BICS controller. The solenoid has two coils, a pull coil and the hold coil. It sounds like either the hold coil is shorting or the circuit that powers it. To get to the solenoid raise the cab. The solenoid is in the top of the chaincase below the seat. The solenoid has two power wires and a black ground wire. The power wire for the pull coil is red or white and the power wire for the hold coil wire is pink or red. The resistance for the hold coil is 0.4 - 0.5 ohms. The resistance for the hold coil is 10-11 ohms. The relay is one of the 4 or 5 relays mounted to a bar right above the battery. The Brake relay harness has 4 wires. Black is ground, Red/White, White, Pink/White. All the relays are the same type. The bar is labeled but be aware you can plug any harness into any relay. These relays can fail in the open or closed position. The BICS powers the relay to close the switch powering the pull coil in the brake solenoid. The BICS also directly powers the hold coil in the brake solenoid. I would start by checking the resistance of the brake solenoid coils, Brake Fuse and relay. You can switch the glow plug relay with the brake relay to check if your problem subsides. When my relays started to go I replaced them all and bolted an extra one on the back side of the mounting bar. That way if one goes bad I can just unplug the harness and plug it into the spare. Since it will start and go, It must be a short some where between the brake solenoid and the BICS controller. Not so obvious, it could be the brake switch opening when you bounce the loader.
My analysis continues Thanks TriHonu for the great information. Here is what I have done so far: 1. Brake solenoid hold coil resistance is 10.4 ohms (normal) 2. Brake solenoid pull coil resistance is 0.5 ohms (normal) 3. Temporarily used the Glow Plug relay in place of Brake relay, no improvement. 4. Disconnected the brake switch on the floor, no improvement. 5. Since the hold circuit short is reported during higher RPMs, I suspected vibration maybe affecting the coil. So I removed the brake solenoid and attached an ohm meter to the hold coil leads. While watching the resistance I tapped the solenoid, vibrated it, etc.... nothing seemed to change the hold coil resistance. 6. With the brake solenoid disconnected I started the machine and the BICS correctly reported the hold coil was open. Suggesting maybe the BICS is operating correctly. As I understand it the hold coil lead is coming directly from the BICS. Seems hard to believe a ground short is occurring somewhere along the wire as its in a plastic webbing all the way back to the BICS. Seems to me the brake solenoid is still somehow bad or changes resistance during operation. OR The BICS is malfunctioning during operation. Any suggestions on how I sort this out?
Another thought... The GND lead of the brake solenoid is not electrically connected to the case of the solenoid. What if the hold coil momentarily shorted to the case? My bench test of attempting to obstruct the hold coil resistance by vibrating the solenoid would have been affected by a short to the case as the case was floating at that point. However when the solenoid is attached to the machine the case would be grounded and therefore an intermittent connection would yield a lower coil resistance. Thoughts? Looks like I may need to go buy another brake solenoid and see what happens... Any idea on how much they cost?
What if the problem is the BICS momentarily loosing its ground and letting the traction lock solenoid snap shut? With the cab raised, you will find a group of ground wires near the cab hinge (behind your left shoulder as you're sitting in the cab). It is common for this connection to corrode and cause numerous issues. Try cleaning this connection to insure the BICS is staying properly grounded. If you have a recording multimeter, hook it up to the hold coil and set to record. Jiggle the ground wire group and see it the hold circuit is loosing power. You may want to run this by the Service Manager at your dealer. I deal with Lano in Ramsey. They have been very helpful when I have gotten stuck on a couple wiring issues.
check to make sure the alternator is not over charging also it may be causing that
just thought of this and disregard the alt post they have a foot brake on those i believe there is a metal tube that runs under the kick plate and the wires a re known to be rubbed or cut there look at that harness and make sure the wires are not cut i got burned by that before so look there it should be right behind the kick plate on the right side of the machine also look at the solenoid by the brake petal also
Thanks bobcatmechanic! I have isolated the foot brake by disconnecting it from the circuit. This eliminates the wiring that goes through that metal tube and the switch itself. I still had the same problem of the traction lock hold circuit shorted to ground under higher RPMs. I have yet to check the BICS ground connection as suggested by TriHonu.
How does the trac lock solenoid operate? I have bought a new solenoid and have off chaincase cover, but piece on the old solenoid that goes down in chaincase is missing. I need to know what keeps that piece from falling out of solenoid?
it is magnetic
which piece there is a 1/4 bolt a small washer a wedge 2 springs and a about 1/2 around solid rod if any is in the chain case start fishing with a magnet if any gets in your chains or bearings its bad news look under the rear drive sprockets in the back corners is where the pieces usallly end up
the coil is magnetic and pulls the brake wedge assembly up when energised and then there is a hold circuit in it to keep it up
I think it is the alt. because it only happens at hi rpm's.
I'm having a similar problem with our 763G, It will not let the brake release after start up. Machine will not move at all, has a code of 17 06(may have that wrong) which says the traction lock solenoid is not grounded. Checked the ground and it seems to be OK. I'm not very familiar with the Bobcat BICS system as this is the only one I've ever worked on. :beatsme
sorry for jumping in but i need help i got a bobcat 863 i parked it yesterday went to go today runs like normal but nothing moves in the indicator spots were the light come on there is nothing not even the power light i looked at all the fuses i could find all good there made shure it was well heated still nothing o ya its a 2001 thanks for any help
try a new cylinoid sp it has probably gone bad internally
what would that be and were would it be can i test it thanks for your reply
lift the cab right inside behind the kick plate or where the steering controls comehtrough there is a chain case cover there are three on the machine one in the front where your feet rest when your running it atleast ming do on an acs machine one right behind the kick plate and one right infront of the hydrostat the middle one right behind the kick plate is where your brake is there will be a gold looking coil if its not covered in oil soaked dirt that is your brake coil i think there is a test for it but don't know it off the top of my head more than likely thats what has gone bad you pull it by taking the 2 7/16 thats the socket size bolts out and pull the coil off and unplug it you can take the entire assembly off which is 2 3/8 bolts or 9/16 socket then you can take the coil off from there you may check the relay on the fuse panel if its a g series triangle lights is how you tell its a g and triangle panels inside that are gray a f series has square head lights on the front if its a f they are in the engine compartment open the back door and its on the left side above the battery third one in is the brake solenoid swap it with the light relay and see if that fixes it if it does replace the relay if not its probably the coil
bump
Make sure the Battery has enough volts to activate the magnet
Hi I have an old skidsteer, I think its a 543 or 553, somebody painted over all the labels before I got it. Anyway I have been having a problem where the BICS will not power up, which has got worse and worse. Having just spent 700USD on an oil cooler and starter motor, I don't want to spend any more. I only use this machine at home, often with a backhoe attachment, for my self build project. What I want to do is replace the BICS with a rocker switch, so once I am sat in, bar down, I press the switch and the Traction Lock Solenoid & Hydraulic Tilt Lock Valve Solenoid engage, and my machine works. The Hydraulic Tilt Lock Valve Solenoid looks easy, 2 wires, one goes to ground, the other the switch. The Traction Lock Solenoid as you have kindly explained above has 2 coils. I am guessing the pull coil needs power initially, then both, then drop power on the pull coil so just power the hold coil, would this be correct ? I am aware that removing the BICS is less safe than with it in place, but I have already glued the seat sensor so it thinks I am always in the seat, so its only really checking the safety bar is in place. Many Thanks Rick
Update To bypass a non working BICS, from a 553C, mid 80's. I am no expert, and I recommend that you don't do this, but if like me the cost of a new BICS exceeds your machines value, what I have done works for me, and may work for you. I really really can't say enough how silly doing this is, and that your machine will be less safe as a result, so don't do it. OK you ignored the safety warning, on your head be it !!! Chock the Bobcat wheels, just in case. Disconnect the battery, red cable only will be fine. Lift up the CAB & secure. I use a ratchet strap. Make sure this is done very very well as you will be working under the CAB. I ran a chunk of 3 core cable from the ignition switch via the CAB hinge down into the motor bay below the seat. Find the Traction Lock Solenoid (in the centre of the machine at the front of the bay under the seat, quite hard to get too), cut the red & pink wires (leave black alone), connect the cut wires from the Solenoid each to a core of the 3 core. Insulate and make tidy. Find the 2 wires going to the Hydraulic Tilt Lock Valve Solenoid. This Solenoid is in the engine bay, but the wires pass near the traction lock solenoid. Cut the green, and connect the end going to the solenoid to the 3rd core in the 3 core. Leave the black alone. Insulate & make tidy. Put cab down, and get to the back of the ignition switch. Connect a wire from the switched live to a suitability mounted rocker switch. On the other side of the rocker switch connect the 3 core wires that run to the green of the Hydraulic Tilt Lock Valve Solenoid, and the pink of the Traction Lock Solenoid. Connect another wire from the switched side of the rocker switch you have just installed to a suitably mounted "press to make and auto release" switch. Connect the other side of this switch to the 3 core wire that goes to red wire on the Traction Lock Solenoid. Insulate all connections and make tidy. Reconnect battery. To drive the bobcat, get in, secure seat bar & seat belt. Start the engine like normal. Set the rocker switch on, peddles to move the arms will now work. Press the push to make, and hear the normal clunk as the brake releases. Drive your machine as normal. When finished, set the rocker switch to off and turn off engine. If you had a working foot brake, which I didn't, it is now not working. Now I hear you ask, what if only my seat sensor is not working, as the seat is old. This is easy. Lift the CAB, chock the machine, disconnect the battery as described above. The seat sensor is under the middle of the seat, unbolt it from the machine, this is harder than it sounds, but not overly hard. The sensor is a magnet in a coil. Rearrange the wires so when the CAB is down you can get to all the bits. Put the CAB down & reconnect the battery. With the machine on, but no engine running, very slowly move the magnet inside the coil till the BICS sees the seat sensor as activated, remember this position. Use some glue, tape, silicone or whatever to hold the magnet in the coil in the position you have just found. Insulate & make tidy. Lets just finish up by saying that your BICS is an essential safety system, and by bypassing any of its functions, as I have described above, you are being monumentally stupid, and may kill yourself or others.
I have a similar problem with th BICS on a 763. The machine starts fine. After the traction override button is pushed the traditional "clunk" is heard. As soon as the right hand control is moved (AHC) to activate the tilt control the valve control light for tilt and lift on the BISC turns off and all control movement is halted. The machine can still drive but no movement of the bucket lift or tilt is allowed. Something to do with the right hand control grounding something out? All replies are appreciated. Thanks
In my machine the wires to the Hydraulic Tilt Lock Valve Solenoid run past the workings of the right hand control. I would suggest that they have rubbed, and the wires have worn through the insulation.
what was the solution to the original problem or was it ever solved? thanks Ryan
bobcat 763 trying to bypass seat sensor in 763 cannot get the lift valve to light up
You can't bypass it by simply joining the wires. What you have to do is take the sensor out of the seat. You will find its 2 bits, a magnet and a coil. You have to work out where in the coil the magnet needs to be, and then using glue / gaffer tape fix the magnet in that position. THIS JOB HAS MANY DANGERS I RECOMMEND YOU DON'T DO IT WITHOUT A RISK ACCESSMENT. Rick
early t190 heater r&r need to get the heater blower motor out but seems like every way i go is a dead end i have the heater core and a/c pulled started to pull the whole duct work and all but seems like the seat needs to come out to get the heads of bolts gotta be doing something wrong any help
You have a more modern model than I, however I had to take the seat out, and lift up the top to get to the bottom of the seat and the sensor.
this is copied from a thread on skidsteer forum for a t200 same problem. hope it helps. Well, I got the motor out after I found all the bolts. There are 4 bolts that hold the whole HVAC system to back/under side of the cab. 2 of the bolts are hidden under foam at the bottom edge of the HVAC unit. Once you drop the HVAC unit you will have access to the blower motor. As I said in my previous post, the bobcat dealer wanted $140 USD for just the motor. I took my motor to NAPA and found the motor for $75 USD. I will try to get that part number and post it. I also took the old motor apart because it just needed a bearing and after I got it apart I found that it does not have standard ball bearings. It is some funky bushing (junk) so repairing the old motor is not an option. I also found out that when the motor starts going out it will last about 5+ more hours if you beat on it and spray the shafts with wd40(a life saver while plowing snow at single digit temps). And when it starts to go out you might blow the 25 amp fuse.
863 bobcat, hydrostat issues New here, just found you guys while searching the net for answers. I apologise up front for not knowing the ropes here. I understand not being able to make a new post or topic or something like that for a while. Anyhow, I'm also fairly new to skidsteers and my 863 tracted pretty good until a hose sprung a leak, I shut it down, pulled the trailer over to it, loaded it, took it to a small shop, they replaced the hose, bucket was jumping and track control was slow to engage when i picked it up, they said it was air in the lines and would clear up, never did, in fact now it doesnt want to move, then it will begin to then wont move again, Hydro fluid looks great on dip stick prior to running, then it looks bubblely, appears to be sucking air into system. Can anyone shine some light over here for me? Thanks
If it looks bubbly I would guess it is still residual air coming through. If it were sucking in air more likely would be foam. Have you operated the boom and bucket cylinders a lot since the hose repair? If not do so and let it sit for a couple hours to let the air come out of the fluid in the tank and do it again. I think the shop should have had it in operating shape when you picked it up. If the drive system was drained the machine should be set up on blocks and run at idle forward and backward so the motors and pumps can turn easily and fill with oil. Check in the book on startup after rebuilding pump or motors.
Boobcat 863 Hydrallic issues I have tried to operate it, When you first start it now, it will not move bucket or wheels, after moveing levers back and forth 4 to 5 times, the wheels will slowly begin to move, then ever so slowly the bucket will begin to respond. you can then move around for 5 to 10 mins and then it will not move at all. shut it down and pull dip stick and it is pretty milky. after allowing to set for 30 min to an hour it will move again. ALSO, if you pull dip stick while moter is running, it will pour fluid out dip stick hole and I do believe it did that before. Man at that shop said it need seals in both drive motors and the Hydrostate. which he quoted $1200 for the motors and $3500 for the hydro. I dont feel good about letting him work on it any more for the machine never had any hydrallic issues prior to that hose springing a leak and it still drove better when I took it to him than when I picked it up. Thanks in advance for any and all feedback.
Boobcat 863 Hydrallic issues I meant to say that I do NOT believe it poured fluid out of dip stick hole before. Dont think it is suppose to do that.
It has been a couple years since I redid the hydrostat in a 632 but I remember the book being very specific on sitting the machine on blocks and and letting it operate slowly to get the air out of the motors and pump. If there is that much air in there to try to operate it under any load at all could cause damage I believe. Hopefully you will get a response from a actual bobcat mechanic on this.
Welcome to the forum AngelRock LLC. :usa Wise choice if ya ask me, wouldn't let him work on it either. Check the suction hose going from tank to pumps very closely, sounds like you might have a poor hose connection that's sucking air when running.
If all was good prior to having the hose replaced, you might want to be sure the hoses are routed correctly (i.e. port A to A, port B to B).Also, if you are getting fluid out of the dipstick only when running you have excessive return pressure (improper hose position ?), if the motors are not leaking externally, pull the case drain lines and measure the amount pumped out in 1 minute (dealer can provide specs.), all will have some case drain oil flow, excessive means your motors are bad. As for the hydrostat, the Sundstrand sets are good for 5K hrs. normally depending on maintenance. If you doubt the pumpset, pull the hydraulic filter and cut it open below the threads, once open you can look inside for brass debris. Also, in the future, if you change a hose dead head the tilt cylinder in curl back position for 20-30 seconds, then recheck oil level, and raise boom to dead head those cylinders, while raised curl the bucket out, and dead head, this will work you hydraulic system over relief and remove the air, those older Bobcats replenish their oil at more than 2 times their reservoir capacity a minute (unrestricted), so they work their air out quickly, they also empty their reservoirs quickly when they lose a drive line or main pump to control valve line. Hope some of this helps.
Check to see if the fill screen is missing- under cap- if it is it could be at the bottom of the tank, resticting the oil feed to the pump and causing return oil to fill the tank. If screen is missing, drain tank and see if it in there.