Toolcat drive issue

[snmirab]

I have a '04 toolcat with about 700 hours on it ... noticed in the Fall a little intermitent laboring while it was traveling. So with out a persistent problem I new it would be hard to troubleshoot. So now it has become completely problematic.

The issue is that only one axle will drive, while the other will not seem to drive at all. After diagnosing it, I have determined that a signal is not being sent to the hydraulic pressure controller on the pump for the rear drive motor. This is causing the rear pump to not drive, only the front. Checked all connections and feel that it is computer related. Conicidentaly the diff lock switch has become non-responsive at the same time. Any ideas what could be causing it? I am hoping that the computer needs recalibration, and not replacement.

 

[timm9]

That's very interesting. While I'm far from knowledgable about technical aspects of the TC's I would expect you would be getting error codes with a warning light on your TC if the issue was a lost "signal". Have you experienced any error codes? Have you had any plugging in your hydraulic fliters? If so you may have a drive motor issue. Is not a 2004 a B series? You might pull your hydraulic filter(s) dump the filter contents into a pan, and carefully cut the filter(s) open and look for brass colored particules in the filters and fluid. There are two filters on a B series with one immediately nest to the battery, and the other near the rear axle under the bed. I also experienced a similar issue with the Diff Lock and it turned out to be a loose connection at the switch under the center console. You can easily check by pulling the rubber pad/arm rest, remove the bolts, pull the cup holder and removed the torx screw and lift up the console. Please post any "discoveries" and remedies.

 

[snmirab]

Surprisingly there are no codes at all, so either it is something deeper than they want a user to see, or it is the computer itself and that is why it is not tripping a code. I don't see it being a drive motor issue because during my troubleshooting I swapped the wires for the front and rear pump pressure controllers. I did this so I could determine if it was the controller on the pump or the signal being sent from the computer. When I did so the problem tranferred to the front axle, and the rear axle started operating properly.

I have it loaded up and will be taking it to the dealer to see if they can reflash it, hopefully that will resolve it, I'll have them test for pump failure if they have time, I need it back for a supposed storm on Monday. I'll post the results when I know more.

 

[pairiefencer]

The problem you are having sounds a lot like the one I have with my 03 A model. It is in the shop right now and they are changing some of the brake discs in the part above the drive motor. They said that would solve the problem but it seems to me that it would be more of a problem along the lines that you discribe? I asked them if there was a wire or switch that sent a signal to the front and rear to unlock or drive? My back wheels would spin and the front was just dead. After about 1/2 hour to 45 minutes of running it would finally take off and drive normally. I had hoped to have it back by this weekend but no such luck. I sure hope they didn't miss the problem and aren't fixing something that wasn't broke? Good luck with yours.

 

[snmirab]

From what I can tell mine does not have any brake pads, the brake pedal is connected to a throttle position sensor when sends a signal back to the computer, so it some how does the braking by hydraulics. Your A model, even though it does have brake pads, doesn't seem characteristic of a brake issue like you are suspecting. The way my 04 model works is a TPS sensor in the accelerator sends a signal to the CPU. There are two variable displacement pumps tandemed together that run the drive motors. One pump for each drive motor. They have solenoid valves that control flow direction ( forward or back). THen a third solenoid looking thing that is the pressure controller. Basically that varies the pressure being put out by the pump depending on how much voltage that is being sent to it. The more pressure more power goes to the motor and consiquently the harder it pulls.

I agree that your machine sounds more of a hydraulic problem. I am hoping that the bobcat techs know the machine and don't feed me the same lines.

 

[snmirab]

Dropped off to dealer this morning. Barring parts availability they are suppose to have it back to me today for tonight's snow. The tech's initial thoughts was a rear wheel speed sensor problem. Apparently they go out alot and cause the shut down of the entire axle if they do not report properly. Bobcat's solution is to reflash the computer and since there are four sensors, set the computer to only read off of the front sensors. That is a Bobcat solution not a dealer solution. He was a little interested in the diff loc not lighting up so he wanted to look a little deeper to make sure that is all it was. I'll update with the final diagnoses and cost later today.

 

[snmirab]

Got the TC back yesterday and seems that everything is working properly, they have not prepared a bill for me yet...
Their best guess is that the speed sensor for the rear axle went out. They did a software update, and that took care of the problem. Apparently the new software by Bobcat sets the machine to only read from the front speed sensor, since it only needs one input. They never did find the problem, only what fixed it, they are assuming that is what occured.


My topspeed went down from 18-19 down to about 14. I can not tell if is actual or not. Since the problem deals with speed sensor I am skeptical about what the digital reading is, so I'll have to do a field test to see where it comes in. From the sound of things on the board, I should fight to get the drive motors replaced if my topspeed is sub 17mph. Anyone have any contacts with bobcat regarding this matter that i can go to?

 

[snmirab]

Oh yeah, I did talked to the tech, and it does have brake pads, everything is internal to the drive axle, so the axle needs to be pulled and split in order to change them... sounds costly..

 

[DEWFPO]

Oh yeah, I did talked to the tech, and it does have brake pads, everything is internal to the drive axle, so the axle needs to be pulled and split in order to change them... sounds costly..

Only if you have to change them. They should last a very, very long time. I haven't heard of anyone having to change them yet.

DEWFPO

 

[J_J]

Oh yeah, I did talked to the tech, and it does have brake pads, everything is internal to the drive axle, so the axle needs to be pulled and split in order to change them... sounds costly..

This is mostly related to the 5600
I believe that your brakes are internal hydraulic activated brakes, and controlled by pressure. When you are going slow or stopped, the brakes are applied when the pressure drops to around 400 to 600 psi and below. When you go fwd or rev, the increase in pressure above the set psi releases the brakes. You might ask your mechanic, that if you drive real slow a lot, will the brakes drag and wear out faster. It's probably a ramp up or down in pressure that is applied. You just do not lock up those brakes unless you lose power, and I don't think you can apply brakes while traveling at a good speed. The hydraulics will usually slow the machine down when you let off the power control. When towing the newer models, you have to screw in some bolts to release the brakes, and remove the shuttle spool, etc.

Some good advice would be to make yourself a hydraulic gage test kit, whereby you can plug in the gage, and know the hydraulic pressure at any significant point. Quick disconnects and a tee in the hydraulic line at those significant points and the test gage will allow you to trouble shoot your hydraulic system. One thing you have to know is a reference pressure, what was the pressure when new. or have the hydraulic schematic with listed pressures. Very few operators have hydraulic schematics, included me. My manufacture does not have one, or will not give me one. Bummer.

 

[snmirab]

Well scratch the "It's Fixed" post. It worked great the day I got it back and two nights ago, though all I did was a test drive a couple hundred feet. This morning with snow on the ground ready to be cleared, it acted up identically to the first time. I am pretty confident that it is temperature related. When I dropped it off and even up till last night, it stayed at temps 40 degrees and plus, this morning it was 29 and the problem was right back. Called Bobcat, they are going to research and see what they can find... It started off intermittent, then became sustained. As I was driving and draging the back axle, I checked for codes 'none' came up...

As far as the breaks go, I have been told the same this by bobcat, that they last VERY long and are hydraulicly applied. I have read some previous threads that the pads " crumbled" and had to be replaced. I don;t think they drag at low speeds becasue I have noticed that if I am on an incline, say a ramp for a trailer, if I just touch the accelerator, the machine will actuall "drift" back until give it more pedal and it builds up ample power to propel forward. From what i can tell, it is a pump pressure issue, because when I swap the pressure controller wires from front to back pumps, the problem swaps to the front axle, so the pump and axle are responding with proper inputs... I might swap the speed sensors from front to back and see what effect that has... Tech saw the axle birping gear oil out of the breather and pointed at that, but I don;t see an issue there, but i'll double check that aswell...
I hate paying for a tech's learning curve at the dealer...

 

[snmirab]

I have not gotten a chance to get it back to the bobcat dealer. Had it out this past weekend and it did the same thing, with air temp at 40. So I let it run for about 1/2 hour and everything ran fine after it warmed up... so it sounds alot like what pairiefencer described with him machine.


pairiefencer, did you ever get your problem resolved? if so, what was discovered?

 

[pairiefencer]

I have not gotten a chance to get it back to the bobcat dealer. Had it out this past weekend and it did the same thing, with air temp at 40. So I let it run for about 1/2 hour and everything ran fine after it warmed up... so it sounds alot like what pairiefencer described with him machine.


pairiefencer, did you ever get your problem resolved? if so, what was discovered?

Just for everybodies info I will post my results. It wasn't the brake issue that the dealer thought. Cost over $1000 and same problem. They then unplugged the rear speed sensor and it works fine except that I get an error message. They claim it will work fine with the speed sensor unplugged. I haven't been driving it much lately since it hasn't snowed. The speed sensor costs over $300. Sounds like snmirab has tried all this already so maybe his problem is more related to hydraulic pressure? This is only the second time I have had work done at this dealer and I have gotten the shaft both times. They said they guarantee their work but I guess that doesn't mean much. Most other mechanics won't touch them because Bobcat doesn't let out their computer programs. Sorry I couldn't be of more help.

 

[snmirab]

It's 29 degrees out and I just started up the TC to duplicate the issue with the rear diff not driving. As planned, it drug it's wheels with only the front driving. Disconnected the rear speed sensor and after ignoring the code fault and lack of speed display, the TC drove normally, plugged it back in and the problem came right back... The rear diff is burping oil and it is caked over the speed sensor, maybe that is the cause, but i am convinced it is the speed sensor now...

I am glad that I posted this board. I owe you a drink praire, thank you very much for you help.

In another unrelated issue, my diff lock was not engaging, after reading other threads and someone suggest it only works in two wheel steering, so I switch it over, and worked like a champ!

 

[rayden25]

Guys try to keep in mind that this is a very complicated machine and there are highly trained individuals designing and supporting this product. You guys are completely off base on how the brakes work. The brakes are only there for parking and they are spring applied and pressure released. The rear speed sensor has been taken out of the software for about a year now. If you have had the software updated within the last year the rear speed sensor is not used anymore. Trust the people at the dealers, they know far more about this product than you may think, additionally they have a direct line to the factory for troubleshooting these problems.

 

[J_J]

You never did say which model you had, a C or D 5600 The bolts are used on the C model. I did find out that there is no good way to tow a disabled D model.

 

[DEWFPO]

Trust the people at the dealers, they know far more about this product than you may think, additionally they have a direct line to the factory for troubleshooting these problems.

That's a broad statement and kinda tough. Everyone needs to scope that out themselves with their local service provider. When I talked to the Service Manager at the dealership a few weeks ago, he didn't know there was a different procedure to be used when towing a "D" Model. The "D"'s have been out for a while now and this guy had quit a bit of experience. He also does a significant portion of the field service work himself (he's been to my place twice to work on my machine).

DEWFPO

 

[J_J]

That's a broad statement and kinda tough. Everyone needs to scope that out themselves with their local service provider. When I talked to the Service Manager at the dealership a few weeks ago, he didn't know there was a different procedure to be used when towing a "D" Model. The "D"'s have been out for a while now and this guy had quit a bit of experience.

DEWFPO

I totally agree. The service manager gave me erroneous data. I don't think everyone of the mechanics go to school on all the new products. It probably works like this. One day, a new model arrives to the dealership with manuals, maybe not. Then someone will learn by doing, and then tell other mechanics about the system. It may be a CD training course that they take home and learn as much as they can before the new TC they just sold comes back in for something or another. Learning is easy, retention is a bit** as you get older.

 

[J_J]

Guys try to keep in mind that this is a very complicated machine and there are highly trained individuals designing and supporting this product. You guys are completely off base on how the brakes work. The brakes are only there for parking and they are spring applied and pressure released. The rear speed sensor has been taken out of the software for about a year now. If you have had the software updated within the last year the rear speed sensor is not used anymore. Trust the people at the dealers, they know far more about this product than you may think, additionally they have a direct line to the factory for troubleshooting these problems.

We know the hydraulic motors have internal brakes, but do you have to apply them, or, or they applied when the hydraulic pressure goes below the spring pressure. Now are these springs manually activated, such as pulling a parking brake lever, or they automatic, such as when the hydraulic motors are at rest. Some where I remember about the brakes are released when the motor hydraulic pressure goes above 600 psi, so that means that between 0 psi and 600 psi, the brakes are on to some degree, and the brake force is usually stated in the specs for the motor.

And NO, I am not way off base, maybe a little, and I bet I could learn your system if I had a new TC-5600, or 5610.

 

[DEWFPO]

We know the hydraulic motors have internal brakes, but do you have to apply them, or, or they applied when the hydraulic pressure goes below the spring pressure. Now are these springs manually activated, such as pulling a parking brake lever, or they automatic, such as when the hydraulic motors are at rest. Some where I remember about the brakes are released when the motor hydraulic pressure goes above 600 psi, so that means that between 0 psi and 600 psi, the brakes are on to some degree, and the brake force is usually stated in the specs for the motor.

And NO, I am not way off base, maybe a little, and I bet I could learn your system if I had a new TC-5600, or 5610.

At slow speeds in Work Mode with less than max. engine rpm (~1900) I can heard the brakes squealing as I'm moving around even at several mph with the bucket on so I guess there's not enough residual pressure to completely release the brakes. Just sounds weird like I'm dragging the brakes. Makes me think I'm wearing them out fast.

The mechanic/Service Manager said it takes about 300-400 psi to release the brakes but I think was a guess based on some experience. I've never actually used my brake pedal to stop the Toolcat, only to keep it from moving again when stopped on a steep hill. It will start to move once stopped on a steep slope.

I'm not sure what actually happens when the brake pedal is pushed.

DEWFPO