If you’ve got a newer piece of CAT construction equipment—like the 120M road grader, 924H wheel loader, D7R II dozer or 621G scraper—you’ve no doubt noticed they come equipped with an ether start aid valve, NSN 4820-01-551-9292.
Inside the valve is a filter that often gets plugged with debris, gets damaged, or just plain comes up missing. Don’t bother looking for it in the TMs. It’s not there!
The filter is available, though. Order it with NSN 2910-01-658-4647 for about $7. That’s a big savings over the cost of a new valve at $196!
Filter NSN 2910-01-658-4647