Bobcat T190

rodneyp10 said:

This is my first hystat so bear with me. If I understand this correctly, the charge oil to the hystat pump is filtered, so no debris should be downstream of the filter.

Click to expand...

Yes and no. The oil does pass through the filter before going to the drive pumps, but if enough debris clogs the filter (such as from a failed gear pump) it will pop open the by-pass valve in the filter housing, junk now goes to the drive pumps. Aside from checking filters as crewchief888 suggested, there's little you can do to check the condition of the system short of complete take apart which is simply not practical.

As crewchief suggested, remove the hydraulic filter and pour the oil in filter into a clean container looking for debris. Once you've poured the filter empty, pour some diesel, kerosene, or solvent in the filter. Place your had over the end of filter and shake it. Now pour the liquid into a clean container to see what comes out. Operate the machine and do a frequent filter change to see what the condition of the oil/debris in filter is.

once again willie has hit the nail on the head.

when you install the new pump, overfill the hyd tank and set the machine sit overnight. this will let oil gravity feed into the pumps so you dont get a dry startup, and cause the same damage to the new pumps.
you may want to install a manual guage in the sender port and spin the engine over, without starting it, untill you see pressure, this will ensure the pumps are full of oil

:drinkup

Me again.................... Installed a new charge/hydraulic pump. Followed you direction for startup.
Initially had about 300 PSI charge pressure and the boom and bucket worked normal.
After it started to warm up, same thing as before, 300 PSI charge pressure until you pull a function and no pressure and no function.
I am loosing pressure down stream someplace.

rodneyp10 said:

Me again.................... Installed a new charge/hydraulic pump. Followed you direction for startup.
Initially had about 300 PSI charge pressure and the boom and bucket worked normal.
After it started to warm up, same thing as before, 300 PSI charge pressure until you pull a function and no pressure and no function.
I am loosing pressure down stream someplace.

Click to expand...

without activating hyd functions, you have charge pressure..
does the brake release and the machine drive normally?

:drinkup

No, lost track function also. Initially the brake released and the track would function.

removed the drive motor hoses from the pumps and cap the fittings off.
start the machine and monitor charge pressure


:drinkup

Im not familiar with the T190 system in particular but when a track motors fail internally they can bypass enough oil that the charge circuit can not keep up. No charge pressure means the brakes will not release as they should. At this point I would be doing the stall tests to see if the pumps are capable of producing adequate pressure. Given the fact that the system runs almost closed it is very possible that damage has been do to both pump and motor. Not what someone wants to hear but is the truth all the same.

The issue is concuqured, two drive motors and a charge pump later.
What oilm can i use in the T190, is AW 46 hydraulic oil ok?

I use a good quality AW46 oil in Bobcat machines.