Yesterday's Tractor Co.
Shop Now View Cart
   Allis Chalmers Case Farmall IH Ford 8N,9N,2N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver
Classified Ads
Photo Ads
Tractor Parts

Discussion Forums
Project Journals
Tractor Town
Your Stories
Show & Pull Guide
Events Calendar
Hauling Schedule

Tractor Photos
Implement Photos
Vintage Photos
Help Identify
Parts & Pieces
Stuck & Troubled
Vintage Ads
Community Album
Photo Ad Archives

Research & Info
Tractor Registry
Tip of the Day
Safety Cartoons
Tractor Values
Serial Numbers
Tune-Up Guide
Paint Codes
List Prices
Production Nbrs
Tune-Up Specs
Torque Values
3-Point Specs

Tractor Games
Just For Kids
Virtual Show
Museum Guide
Memorial Page
Feedback Form

Yesterday's Tractors Facebook Page

Related Sites
Tractor Shed
Ford 8N/9N Club
Today's Tractors
Garden Tractors
Classic Trucks
Kountry Life
Crawlers, Dozers, Loaders & Backhoes Discussion Forum

Re: hitachi 120-3 hydraulic problem, need shop manual

[Show Entire Topic]  

Welcome Guest, Log in or Register
Author  [Modern View]

07-26-2012 10:56:03

Report to Moderator

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.

[Log in to Reply]   [No Email]
[Show Entire Topic]     [Options]  [Printer Friendly]  [Posting Help]  [Return to Forum]   [Log in to Reply]

Hop to:

Fast Shipping!  Most of our stocked parts ship within 24 hours (M-Th). 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. [ About Us ]

Home  |  Forums

Copyright © 1997-2016 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy

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