The CAT E70B excavator is a machine that we use for digging, building, and many other purposes. Every day we find a solution to any problem it faces, but sometimes it is difficult to solving them because they are more complicated. The post will present some problems and solutions by which you make your work easier with CAT E70B.

Cat E70B excavator bucket stuck

The E70B is a relatively old and small excavator, not particularly suited for heavy duty work.

The most likely cause of the bucket getting stuck is that it’s been forced into an overloaded condition by driving forward over material that’s too hard or too thick to penetrate easily. The pressure from the weight of the machine, plus the digging force from the bucket cylinders, can jam a bucket in place. The only way back is to drive out forward.

The way to resolve this problem, in future, is to use less force. This might involve using the bucket as a lever, using something like a rock bar to pry material loose, or even pulling back on the boom and pushing material out of the way with the underside of the boom cylinder. As a last resort, use of a hydraulic hammer may be required — but this will probably be difficult to do on such a small machine.

Cat E70B excavator

Cat E70B excavator swing brake dosen’t hold

When the service brake is applied, it shows 2000 PSI on the gauge. Is this normal? No, should be lower. The service brake is actually the swing brake, so this means the service brake is applying when you don’t want it to. This can cause a lot of weird problems.

Does the excavator have pilot controls? Answer yes or no. If pilot controls are installed then you will need to disconnect the pilot control valve and test it individually to see if its causing any of these problems.

Have you checked the oil level in the hydraulic tank? If there is too much oil in the hydraulic tank then it can cause hydraulic fluid to leak into the swing brake chamber and release pressure from the swing brake causing a loss of holding power.

Cat E70B excavator hydraulic leakage

I am working on a Cat E70B excavator with hydraulic leakage on the swing motor. I was wondering if anyone has any common problems that they’ve ran into before with these and what the fix is. This machine is only a 1970, but I’ve never been able to find much information on them.

I just started working on this machine today and there’s hydraulic fluid everywhere, so it’s going to take some time to get it cleaned up and figure out where everything goes. When I shut down the engine there’s a small leak that comes from the top of the swing motor, but no big streams.

Cat E70B excavator circuit breaker blown

I have a Cat E70B excavator that has had a generator system problem for about 2 years. It would blow the circuit breaker on the right side of the machine under certain conditions. We have replaced that breaker with another one several times.(the breaker is a plug in type) I bought a new one and it blew out as soon as we plugged it in.

I had a mechanic look at it recently and he said the machine needed a new computer board and replaced it. I went to hook up the machine today and it blew out the new breaker again. I unplugged the electric fan motor in front of the radiator and the circuit worked, but when I plugged it back in…it blew again.

My question is…is there a way to tell what is causing this short? The fan motor doesn’t seem like its drawing enough power to cause this problem unless something else is wrong inside that motor which would cause higher amperage usage?

Cat E70B excavator Steering System Problem

The Cat E70B excavator has a steering system that uses a hydraulic cylinder mounted behind the cab. It connects to a rack and pinion gear via bellcrank at the front of the machine. It’s controlled by a foot pedal that opens and closes a valve, which sends oil to either side of the cylinder. The cylinder is connected to the bellcrank with a rod end, which can turn 90 degrees. The bellcrank is attached to a rock shaft that turns the pinion gear. The pinion gear then moves along the rack gear, which is attached to a steering box that mounts on top of the front axle.

The problem was an undercarriage repair shop had replaced all four corners of the E70B. After they had done this they got in it and tried to move it forward, but it would not move, although you could hear the engine running. Then they tried to move it backwards and it moved backwards just fine.

Upon further inspection I found that when we put it into forward gear, it would only go as far as about half way through its travel, then stop moving. It would still be engaged in forward gear but no more movement would take place past.

Cat E70B excavator Electrical system problem

The Cat E70B excavator suffered from electrical problems. The engine would start but the main hydraulic system would not operate. I checked all fuses and all were good and could hear the fuel pump running when the key was turned on.

The problem turned out to be a bad connection between the solenoid control unit at the front of the machine, behind the cab. A small cylinder with a wire going into it about 1 inch in diameter that is mounted just above where the track frame connects to the body of the machine. I took a small screwdriver and pushed down on each of the three electrical plugs that go into this unit and found one that had corrosion on it. It appeared that some rain water had entered this connection and caused corrosion in this plug.

I cleaned up this plug with sandpaper and plugged it back together and now everything works fine again!

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