Liebherr 631B track loader electrical problem

[UwharrieBoy]

I have a 1992 Liebherr 631B loader, made in Germany with a Mercedes engine. Tough machine. Very little problems. Recently it would not start except by jumping the starter relay positive and negative terminals with a wrench and simultaneously turning ignition switch to start. Replaced the relay. Should have known that wasn't the problem because the electrical system would not shut down without jumping the terminals again without turning ignition key to start.
There must be another relay somewhere. My suspicion is it may be connected to some safety feature.

Does anyone have any ideas? Thanks.

 

[J Black]

There is a safety switch located under the parking brake lever under the left hand joystick. That switch will interrupt the start circuit if it's not functioning properly. You can try temporarily bypassing that switch to see if that's the problem.

 

[bull]

I have a 631b with the same problem. When you figure it out, sure would appreciate if you would post your findings.

Thanks much.

 

[UwharrieBoy]

We are thinking it may be the ignition. The problem started when the machine started beeping one day with a low battery warning. The switch key was in off position but fans, guages, and lights were all on just as if key was turned to run.

Thanks J. Black. We've checked the switch located on the servo valve and it is working.

The fact that the machine will not turn off without disconnecting the switch ignition wire makes me think it is the ignition.

Bull, does your electrical system stay on when you turn the key off?

Thank you all for your help.

 

[bull]

Nope, ours is dead when key is off.

We are thinking it may be the ignition. The problem started when the machine started beeping one day with a low battery warning. The switch key was in off position but fans, guages, and lights were all on just as if key was turned to run.

Thanks J. Black. We've checked the switch located on the servo valve and it is working.

The fact that the machine will not turn off without disconnecting the switch ignition wire makes me think it is the ignition.

Bull, does your electrical system stay on when you turn the key off?

Thank you all for your help.

 

[UwharrieBoy]

Nope, ours is dead when key is off.

Bull, maybe yours is the relay. The Liebherr dealer wanted over $600 for the relay. I found a local hydraulic cylinder/ electric motor repair shop in Denton NC and the guy got a relay for us for $300. So don't be taken to the cleaners by the dealer. It was the same Bosch relay, model number and everything. I know because I ordered some other parts and the dealer sent me the relay accidentally because we talked about it. I sent it back.

 

[J Black]

I don't have a wiring diagram in front of me right now, but the liebherr machines that I have had would keep the electrical in the cab/dash, on the entire time the engine was running, whether the switch was on or off. The regulator in the alternator completes the circuit, once it starts charging, and doesn't break the circuit until it stops spinning. I have a diagram I can look at Tuesday, if you need me to.

 

[bull]

Bull, maybe yours is the relay. The Liebherr dealer wanted over $600 for the relay. I found a local hydraulic cylinder/ electric motor repair shop in Denton NC and the guy got a relay for us for $300. So don't be taken to the cleaners by the dealer. It was the same Bosch relay, model number and everything. I know because I ordered some other parts and the dealer sent me the relay accidentally because we talked about it. I sent it back.

Thanks much for the response.

Is that the relay that the battery cable goes to? The one that clicks loudly when the key is turned on.?

Thanks again.

 

[J Black]

The clicking you are talking about is the master battery disconnect. It's located near the batteries, and breaks the ground side of the circuit. The relays are located inside the instrument cluster.

 

[bull]

Bull, maybe yours is the relay. The Liebherr dealer wanted over $600 for the relay. I found a local hydraulic cylinder/ electric motor repair shop in Denton NC and the guy got a relay for us for $300. So don't be taken to the cleaners by the dealer. It was the same Bosch relay, model number and everything. I know because I ordered some other parts and the dealer sent me the relay accidentally because we talked about it. I sent it back.

You wouldn't happen to recall that relay part number, would you?

Just might be my problem.

Thanks much.

 

[Rvaitor]

I have a couple problems. One the upper oil line busted at the top connection to the oil cooler. I am not sure how to get to the lower connection? Do I or should lift the cab 631b btw? I have manuals but not reference to how you lift the cab I thought about taking the bottom plate off but still don't think I could reach it. Located in NC. Thanks

 

[cb75]

On a 641 loader, to raise the cab you must remove the neutral safety lever, the air breather, move the throttle and shut off levers to their center position, remove 3 or 4? Cab mount bolts on each side, then use the Jack to raise it until the safety pin can be inserted. Also, if you have a floor mounted control pedal for a 4-1 bucket, you must remove the floor mat and a cover that goes around the pedal.
Again, this is on a 641. I'm not familiar with 631's. But from what I remember, they were similar.

 

[cb75]

Forgot to say that, yes raising the cab allows decent access to the hydraulic components of the machine.

 

[bull]

While we are on the subject, does anyone know of any place that has used parts for a 631b?

Thanks.

 

[Rvaitor]

All this makes sense. Thanks and I do have the 4n1. Not sure on the jack point and safety pin/lever. I also have an unusual exhaust system - dual cherry bombs/sounds incredible! So I still need to sort out the jack issue but will look into it tomorrow.

 

[cb75]

Our 641 loaders came equipped with a cab Jack. The pump for it was mounted inside the right side engine compartment.

 

[cb75]

Here is a pic of the engine compartment. The pump for cab jack is at the bottom right side. http://static.mascus.com/image/product/large/rolpap/liebherr-lr-631b,670_7.jpg

 

[cb75]

Once the cab is up, look under it, beside the fuel tank and there should be a 2 piece safety brace with holes that when aligned you insert the safety pin. The pin should be red and stored in a small piece of tube welded to the tank. If it's not there, you can use a properly sized bolt and nut.

 

[Rvaitor]

This is the setup I have will look at everything today thanks so much for your help,I will let you know how it turns out.

 

[Rvaitor]

OK I was not able to lift the cab I did remove the four bolts behind the doors loosened the pedal that controls the bucket 4n1 but there must be something else . Does anyone have the instructions or a reference I can't find d it in the manuals I have? Really appreciate the help so far.