Guys, I have purchased a 1989 Krupp 4055 crane for resale and I am having an issue with the boom not extending. All other functions work. The counterweights are currently off of the machine and am wondering if there is a safety switch that would need to be activated by loading the counterweights to get the boom to extend. If any Krupp experts are in the Minnesota area or anywhere for that matter I would greatly appreciate some help. Feel free to give me a call at 813-478-3802.
If it was an a2b malfunction it would cut the boom down and cable up. Check the charts and see if it has a 0 cw load chart. If I was a betting man I'd bet the switch that switches the controller from boom up and down to boom in and out is not working. Start with the switch and follow it the valve and I'll bet you'll find the problem.
Knepptune, I appreciate the feedback immensely. Is there anyway to by pass that switch in the short term? The operator said you can hear the hydraulics engage and load up, but it won't extend the boom. If you had 5 minutes to explain this to my operator when he goes to the crane today, I would be forever indebted. 813-478-3802- Matt
Might be worth grabbing an engineer to take look. Did you get the manual with the sale? can try giving these guys a call if you have trouble, sure they know what they are doing. Don't think they will charge anything. Good to get some expert help if you are ensure. We don't want any safety issue to result if there is a problem with the machinery, especially when heavy loads are involved.