Swing brake help

1. #1John C.2011-09-05 20:19

   Which Dash series Komatsu do you have? The automatic function is in the computer on most models and the fact that you can throw the prolux switch and get the house to swing means the solenoid and the brake itself is OK. I think there is a diode on there that could be the problem and sometimes the wire harness goes bad if it has had a lot of hydraulic oil soaking it for a long time. I don't recall where the diode is on older models so I need to know what your machine is before I can send you into dark places looking.

2. #2Drtdigger42011-09-05 20:45

   I'll get all the info off it tomorrow I really appreciate your help

3. #3Drtdigger42011-09-06 10:57

   That track hoe is a 08 komatau pc200-lc serial number a88803 It's got both piolot controls leakin out the 4 pistons I'm gonna replace those seals today. Would that effect the swing brake if those seals are leakin?

4. #4michel2011-09-06 11:22

   The only way to troubleshoot ur machine is to put a gauge on the swing brake hose using a Tee adaptor so you can check the pressure on the swing brake while operating the swing, good luck

5. #5John C.2011-09-06 21:56

   The leaking hand controllers cannot cause a problem in the swing brake. Maybe you better explain some more about what is going wrong. Shifting the prolux swing releases the swing brake all the time unless you set it on the panel. Most of the time people shift that swing and forget they did it. They will run for years until the swing motor wears out and the swing starts drifting. I suspect from your description of the leaking hand controller that your machine has been continually overheated to the point of cooking out the rubber seals. That kind of damage comes from plugged radiators and oil coolers. At any rate please describe what the machine is doing that makes you say the swing brake has a problem.

6. #6jpz 1232012-01-17 19:46

   I have a sinular broblem PC220 see next entry

7. #7jpz 1232012-01-17 19:49

   I have a sinular broblem PC220 Does the power to the solenoids switch the negative or the positive. Mine has Positive but no negative

8. #8John C.2012-01-17 21:23

   There should be two wires on the solenoids. One is hot all the time and the other grounds in the computer. The computer controls all the electrical system by making ground which allows current to flow.

9. #9pinesd34002012-01-18 07:06

   sorry computor had a moment Having another computor meltdown

10. #10jpz 1232012-01-18 18:45

    Thank you for the information. Tomorrow I'm scheduled to work on that 220

11. #11jpz 1232012-01-19 18:46

    Help Again! With that PC220 swing brake which I"m in the process of trying to fix. The dealer was quite helpful by giving me a couple of pages from the service manual. So I'm reduced to two possible problems. The swing brake solenoid is bad since the ohms are 70 vs 10-35. but that little handful of copper is $800 is it available aftermarket? The second possible problem is a weak ground which is the switched leg I'm only getting 19.2 volts to a good positive Hence a bad connection?

12. #12AirBornOne2012-02-11 07:50

    Measuring ohms in that low of a range can Really benefit from having a good meter & connections.Just probing can give that much variation in readings. A high resistance ground can be a source for lots of headaches. Are connectors used or is this hardwired? Either way check/clean the connections-tighten if needed. A lot of the older plastic bodied connectors can be dis-assembled for cleaning or re-tensioning of the spring contacts.Or just replaced. Have fun. J.

13. #13jpz 1232012-02-12 18:42

    Thank you for your response. I replaced the swing brake solenoid which included the valve body solving the problem.