From time to time a customer will ask us for help with a mechanical/hydraulic issue … mostly for bucket trucks, but also for digger derricks. For that type of call we open the unit’s manual and turn to the utility vehicle manual as our main troubleshooting guide.
We want to take this opportunity to review some of the more common questions we get. With that comes our disclaimer: we are not professional mechanics, but we did stay at a Holiday Inn last night! 😆 Actually, our disclaimer states that we are not professional mechanics, but if we have the unit’s manual handy, we can look it up and hopefully we can be of some help.
We get a lot of questions about the boom circuits. Here’s a common one: My lower boom raises, but I can’t get it down. Depending on where the truck is, this can be especially troublesome. Troubleshooting guides give a couple of possible causes and remedies. The most probable cause here is a defective counterbalance valve. There aren’t many options here – the valve probably needs to be replaced.
Running a close second in frequency is that the upper boom raises, but will not lower. It’s possible there is a problem with pilot pressure to the holding valve, or maybe the valve is malfunctioning. Again, it may be necessary to replace the valve.
Maybe I can get one more in before you hit the delete button … I get no response when trying to operate the upper control valves. Your first thought should be to make sure the PTO is engaged. Duh! If the PTO is engaged, check the level of the hydraulic oil supply. It may be low.
Troubleshooting guides can offer as many as ten or so checks to make, ruling out the most obvious things first.
UEP offers manuals for most makes and models of bucket trucks. The manuals cover operations, maintenance, service, and troubleshooting. In addition, the manuals contain parts lists and detailed engineering drawings of systems and select parts.
Contact UEP today to purchase the manual needed for understanding, maintaining and operating your bucket truck!
The “UEP” Guys 
“We Know Parts!”