Topic: Re: hitachi 120-3 hydraulic problem, need shop manual
|Crawlers, Dozers, Loaders & Backhoes Discussion Forum|
[Show Entire Topic] [Return to Forum]
[Show Entire Topic]
[Return to Forum]
[Add a Reply]
Thanks Wayne. I've got a bad feeling it's the pump, but I guess I'll need to buy a book for it to save the mechanic some time. He's good (and 100% honest), just not schooled on Hitachi. Could get the Pape guy out, I just don't know anything about the mechanics there and I don't like the mega-corp monopoly mentality.
As to the "renting it out" comment, I don't blame the guy, it's just that most machines I've known can tell when there's a new guy in the seat, and they often take advantage of it. The last time I let out it came back with a torn seal on the swing motor.
[Reply] [No Email]|
| Glad to hear you have someone you can trust and is good enough to work on your machine. That said, if your guy has a flow meter with a true load valve arrangement (ie one with a rupture disc just in case he's loading it and the pump is the problem) and is as good as you say, he shouldn't need a book to do the flow test, except to get the exact specs. Given the problem exact specs probably aren't going to be needed as a sudden spike, drop, etc in flow and/or pressure will usually be so far outside of the norm that they will be obvious. |
I've worked on several different brands and the usual way to flow test a main pump is to tie into the line directly off the pump being tested while capping the downstream side going to the valve body. Instead of going into, and out of the valve block like normal, the return flow goes into a T fitting put inline where the oil returns from the swing motor. With the meter hooked up being fed oil from the pump, and returning it to the T in the swing motor line, you can then start the machine. From there all thats left is to slowly close the load valve to load the pump, and see what happens. On a machine that size I'd guess your flow would be in the range of 30 to 40 GPM at around 5000 psi. Given the problem you might have to run it for awhile under a load to get everything warmed up so it will act up. I once ran one for nearly 30 minutes, under a load, before anything happened. Then what happened was the swash plate finally decided to move and when it did the surge created by the additional oil created a pressure spike that blew the 6000 psi rupture disc in my meter. That's why I mentioned earlier that to do a test in a situation like this a rupture disc in the flow meter is a must.
Good luck, and holler if you run into any problems along the way. I'll be glad to help out as much as I can.
[Reply] [No Email]|
|Same-Day Shipping! Most of our stocked parts ship the same day you order (M-F). Expedited shipping available, just call! Most prices for parts and manuals are below our competitors. Compare our super low shipping rates! We have the parts you need to repair your tractor. We are a Company you can trust and have generous return policies! Shop Online Today or call our friendly sales staff toll free (800) 853-2651. [ More Info ]|
| Copyright © 1997-2013 Yesterday's Tractor Co.|
TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.
Yesterday's Tractors - Antique Tractor Headquarters
|About this site - Yesterday's Tractors is your one-stop source for antique tractors. If you are interested in older tractors you've come to the right place! Join more than 275,000 other classic tractor enthusiasts from all over the globe. We have many resources for antique tractor enthusiasts available including photos, classified ads, more than 24 tractor discussion forums, a show guide, values, specs and much more. Bookmark this site and come back often. Thanks for stopping by! Feel free to use our feedback form to send us your comments, suggestions and ideas.|