After long time use, PHB-3000 Brinell hardness tester hydraulic oil will lose and the remaining volume is not enough to produce proper movement of indenter, so that it can not apply full scale of 3000kg test force on the specimen.
And the judgment method as below:
1. Checking the hydraulic sump
Take off the pressure lever and check if there is oil near the bronze bushing. If there is, it means the O ring in the bronze bushing is worn. Both of the O ring and the bushing need to be changed for new ones. The operation process of it is as following:
Take off the test head from the carriage, make the sump upside and put it on the desk. During this process, take care of avoid oil leakage.
Use the special wrench for bronze busing to take the bronze bushing off. The bronze bushing has a left- hand thread which is different from other threads, so turn it clockwise. An O ring will be found in the bronze bushing. If the O ring wears, some oil leak from bronze bushing. Fill the hydraulic oil overflowing around the bronze bushing. Clean the test head with soft cloth and cleaning fluid and install back the test head.
Other parts of the hydraulic sump can not be taken down or changed except for bronze bushing and O ring.