Got a stupid - but simple - question... We've got a very worn 80's vintage D7G that spends the vast amount of its time parked and rusting out wherever it was last used. Was running it today to improve/rock a road for logging access - a hefty challenge with all the worn pins, bushings, et. al. (makes great speed bumps though) - when I looked over and lo and behold, the cap on the hydraulic tank was AWOL. Dozer has a cab with (mostly) intact glass, so I didn't catch a wiff or notice any splatter of hydro oil when it happened, but reasonably sure it happened today - oil splatter on the tank side was fresh and light, no garbage in/on/down the filler neck, clean threads, etc. That and the only other guy who moves it occasionally (notice I didn't say "operates", or even "drives"...) claims it was there when he moved it yesterday. 'Course he's also always the first to claim "wasn't me!!" whenever tires are flat, low/no oil in tractors, tools lost/missing... The stupid question is, was that cap a simple solid cap - meaning I could hit the hardware store for a pipe cap and be back in business - or was it a vented or some other oddball cap that I can only get from CAT? Its been so long since I've had to add hydro fluid to it I don't remember exactly what the thing looked like, except it being yellow (ish) and something like a cap (duh...). PK
Should not be vented.
Agree with Don. The cap is not vented. However the OEM Cap has a nifty system in it to release any pressure in the tank without spraying oil everywhere, the tank is designed to pressurize when the oil gets to operating temperture. If you bought a "will fit" replacement it wouldn't have that. You need items 1 thru 4 (Ball, plate, gasket, & cap) on Don's illustration. The Part Numbers are 4B-9782, 6H-5139, 9H-6454, & 7H-1447 respectively.
Thanks gentlemen - got a temporary cap clamped down on it for now to keep the crap out. Apparently it's an oddball size/thread, so a standard pipe cap won't fit, will have to get the right one from Cat. At least I was able to finish out the section and beat the rain coming tomorrow. PK