B7100 FEL question

[2drx4]

I just bought a B7100D and it has a FEL on it. No idea who made it, or if it's factory, or what.

Anyway, I'm changing all the oils to catch the servicing back up, and it appears there is no drain on the FEL's reservoir. It's the typical design where the upright on the controlling side is used as the reservoir.

Is there any reason I shouldn't drill a hole in it and weld a NPT bung on it? Or should I just pull the pump feed line off and drain it there? The pump feed port is several inches above the bottom of the reservoir, so if I do that I'd want to try to suck out whatever crud might be in the bottom I guess.

I took the fill/breather off the top and definitely watched a chunky of mangy old teflon tape fall in the reservoir, hence being more concerned than I might be otherwise. I'm not sure if there's a pump inlet screen or not either, I'd assume if there is that it would actually be on the pump?

 

[Lil Foot]

If it is a B219 FEL, (most common on B7100s, 1st two pics) the fitting that the arrow points to is actually a screen that doubles as a drain plug.

 

[2drx4]

Okay, thanks, it appears to be that FEL. The fitting stackup there is different, I'll pull it apart and see if there's a screen there and try to suck out the remaining oil.

 

[2drx4]

I pulled that fitting, and yup, there's a screen in there that's covered in crud. The bottom of the reservoir was also covered in crud and metal flakes (probably from pipe threads). I sucked most of the oil out from below the supply fitting with big syringe and piece of hose. The oil in the top of the reservoir looked okay, a bit dirty, but the stuff in the bottom was black sludge, the picture doesn't really do it justice. I cleaned everything up with rags and brake clean the best I could, it's not perfect, but probably 99% better.

Now the debate is if I should try to flush the rest of the system or not.

I honestly think the system should have had a drain fitting at the actual bottom. I don't imagine it will matter for the remaining life of the machine though.

 

[Lil Foot]

I honestly think the system should have had a drain fitting at the actual bottom.

I had the same thought when I did the initial cleanup on mine, and I almost drilled & tapped the bottom of the reservoir for a pipe plug, but then I rationalized I would probably never need to do a major cleanup again.
Mine had been running without a vent cap, just a rag wrapped around it. Remedied that right away.

I drained the fluid, filled with clean fluid, ran it for a day, then drained it again. Refilled with clean fluid again, then ran it several years.

The next time I drained the fluid, it was VERY clean, the screen was spotless, so I think it will go without a fluid change for many years to come.