I recently acquired an old Cat240B excavator. It’s a nice, tight machine but it has been sitting a couple years. Once we got it going we noticed it won’t swing at all. The motor lugs down like it’s under pressure when you try to swing it but it won’t budge at all. I researched that there is likely a swing brake but I’ve been unable to find any information on where the switch or the solenoid for the brake would be on this model. Does anyone have any experience with this? Thank you.
I assume you mean an EL240.? I see three distinct series of machines. Do you have a machine Serial Number.?
Yes an EL240
Confirms my suspicions. Need a Serial Number to confirm if you have an A, B, or C model. Based on that we find the technical information regarding how the swing brake works.
It is a B model
OK, that makes it either a 5WG or a 6MG machine. The former model was sold in the US, the latter was a grey import and finding info for it is as rare as finding hen's teeth. Again a machine Serial Number is key to finding technical information if you have one to hand. To the best of my knowledge the swing brake is operated by pilot pressure so that when the swing control is operated the same pressure that operates the spool in the swing section of the main control valve also releases the brake. The brake is contained in the top of the swing motor. Most excavators of that era also had a "free swing" system controlled by a switch in the cab. That system operated a solenoid valve that supplied pilot pressure via a solenoid valve to the swing brake and permanently released it so long as the swing release switch was in the "Free Swing" position, or until the engine was shut down. The attached may be of some help.
Does it have a safety pin that prevents it swinging for transport?
Not that I’ve found. The previous owner would have had to install it and he didn’t seem to know anything about it.
Pages 7 & 8 of this attrachment contain information about the controls including the swing lock pin and the location of the swing brake release switch, but I have to stress that the swing should work fine whatever position the switch is in.
Thank you for the replies. With that being said, it would seem like maybe the solenoid isn’t functioning then?
Unless you have already eliminated the possibility that either the swing lock pin is in the down position or that the swing brake assembly could be seized up I find it somewhat difficult to understand how you could come to that conclusion.
Well as stated previously, I don’t believe the swing brake lock pin could be in place. But what are you calling the swing brake assembly? I thought the swing was a hydraulic motor in a bearing and the brake was operated by a solenoid that restricted fluid to the swing motor?
Inside the swing motor is a multi-disc brake that is spring-applied and released by oil pressure - pilot oil pressure as I explained earlier. I know that the attachment in Post #4 was a bit on the large side but it does explain how the swing function works. The text below from Page 96. The information is for an EL240B of 5WG prefix. If you would care to mention your particular machine Serial Number I can confirm whether or not it is correct.
Thank you for the responses. After a lot of troubleshooting today I realized someone had hot wired the key straight to the starter so all of the other electronics have been bypassed. There’s no power getting to the solenoids, including the swing brake solenoid. Or the pressure switch. So now I will be looking for a wire schematic for the key switch to try to rewire it back to original.
I can help you with that but when I did a brief investigation yesterday I found there were a number of different ones depending on the machine Serial Number.
Mine is the more common 5wg
That's good to know, because there are no schematics listed for the 6MG machines. Check your message inbox.