One of the most discussed problems that people confront me with is hydraulics in nature. Whether it be about what hydraulic fluid to use; what pressure hose to use; why some hydraulic fluid is black, clear or red in color; can I top-off the system with the clear fluid if it already has red fluid in it; can I mix the two? Questions like these, I get on a regular basis.

    So I am going to discuss a seemingly easy problem that became not so easy to one of my callers. He stated that he was responsible for a Tennant Model 8200. This machine is considered a mid-sized rider sweeper/scrubber. This would fit well in a 100,00 to 250,000 square foot warehouse.

    As far as hydraulic motors, the machine consisted of a main brush motor, side brush motor and either two or three scrub brush motor options. He stated that the sweeper/scrubber had about 700 hours in his maintenance log when the side brush motor started to leak. It is a relatively easy job to rebuild, being an A Series Motor with rear ports. He stated that he rebuilt it without a hitch and reinstalled the motor. "No leaks." Approximately one to two weeks went by and, again, it was leaking. Accordingly his maintenance log was around 60 hours.

    Next, he bought another repair kit and, again, rebuilt the motor. When he took it apart he double-checked for internal parts for damage, but there were none. Again, it was reinstalled on the unit. Keeping a close watch, he said he checked the motor every day. Around two weeks, actually, 72 hours in service, it began to leak abruptly and got worse. So he said he had to again pull it from the floor.

    When I was contacted he soundly defended how he rebuilt them. He honestly did not know what to do except, perhaps, give up the idea of rebuilding it and just buy a new motor. Read and find out what I told him.

    First some questions I needed answers for:

        1. Where did he purchase the repair kits? He stated that a hydraulic shop

        sold them to him. They looked them up with the number on the motor.

        2. What color is the hydraulic fluid? He said it was red.

    I did not have to hear more because I had the answer.

    First of all his rebuilding methods were just fine and not at all at fault. The red hydraulic fluid is a DuPont product that Tennant uses because it is explosion-proof/non-combustible. Many companies require this for one reason, or another. The system has this fluid, however, the downside is that it deteriorates ordinary seals made of Buna-N.

    For the conclusion of the article see next month's Creamer Corner.

    As always I appreciate your comments and input. If you have any questions or comments you can e-mail me at mikec98423@yahoo.com or call at 1-800-346-2319.