Welcome! Please use the navigational links to explore our website.
PartsASAP LogoCompany Logo (800) 853-2651

Shop Now

   Allis Chalmers Case Farmall IH Ford 8N,9N,2N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver

Attention Forum Users: On the 28th of December 2023 at 9:00am Central Time, we will be taking the forums down for maintenance while we prepare the new forums for your use. Please click here for more information.

John Deere Tractors Discussion Forum
:

8640 hydraulic flow

Welcome Guest, Log in or Register
Author 
Attila

04-14-2007 07:54:42




Report to Moderator

My 8640 seems to have lost 50% of the hydraulic flow to the remote connections. It seems slow now in raising any implement or operating my air seeder. Would the pump have gone on me or would a valve be stuck open somewhere reducing the flow to the remote cylinder connections. Any help would be appreciated.




[Log in to Reply]   [No Email]
Bob

04-15-2007 00:33:01




Report to Moderator
 Re: 8640 hydraulic flow in reply to Attila, 04-14-2007 07:54:42  
1.) Have you changed the hydraulic filters, and was there anything in them (clutch or brake material or metal filings)?

2.) Is there any abnormal heating of the hydraulic system? A "high pressure leak" that keeps the pump "in stroke" all the time will make the system run hotter than usual.

3.) If neither of the above apply, it's going to take a little detective work with a flow meter test set and a factory service manual to be SURE if the problem is the main ( front pump), or some other obscure problem with the hydraulic system.

[Log in to Reply]  [No Email]
attila

04-15-2007 12:06:19




Report to Moderator
 Re: 8640 hydraulic flow in reply to Bob, 04-15-2007 00:33:01  
Yes Bob: I did replace the hydraulic filters and there was no metal filings or material visible. There has been no abnormal heating of the hydraulic system. When I first noticed the reduced flow was when I was seeding. The hydraulics were working good then when raising the drill the fan speed (hydraulic) reduced sharply. The following morning I did replace the filters but this did not solve the problem.

[Log in to Reply]  [No Email]
G/MAN

04-16-2007 18:05:31




Report to Moderator
 Re: 8640 hydraulic flow in reply to attila, 04-15-2007 12:06:19  
Right off the top of my head I'd suspect a problem in the stroke-control valve area of the pump control valve block mounted on the front of the pump. The spools and valves in that block are the items that allow the pump to go into and out of "stroke" in order to maintain proper system pressure at all times, regardless of the amount of oil required. The problem either lies there or there is some sort of internal leak somewhere preventing the main pump from getting all the oil it should be getting from the transmission pump, which acts as the "charge pump" for the system. An internal leak could be allowing much of that charge oil to be lost. Your best option in order to avoid throwing parts at the thing hoping to fix it is to get the Deere manual and proper test equipment and start doing the step-by-step troubleshooting the hydraulic system diagnostics section lays out. Skipping steps is not recommended, and proper troubleshooting will locate and fix the issue in the most time and cost efficient manner possible.

[Log in to Reply]  [No Email]
Bob

04-15-2007 00:32:57




Report to Moderator
 Re: 8640 hydraulic flow in reply to Attila, 04-14-2007 07:54:42  
1.) Have you changed the hydraulic filters, and was there anything in them (clutch or brake material or metal filings)?

2.) Is there any abnormal heating of the hydraulic system? A "high pressure leak" that keeps the pump "in stroke" all the time will make the system run hotter than usual.

3.) If neither of the above apply, it's going to take a little detective work with a flow meter test set and a factory service manual to be SURE if the problem is the main ( front pump), or some other obscure problem with the hydraulic system.

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

Hop to:


TRACTOR PARTS TRACTOR MANUALS
We sell tractor parts!  We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]

Home  |  Forums


Copyright © 1997-2023 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

Website Accessibility Policy