Welcome! Please use the navigational links on your left to explore our website.

Company Logo Shop Now
   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
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
Kountry Life
Ford 9N, 2N & 8N Discussion Forum
Order Ford 8N Parts Online

Safety relief 8n

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

02-21-2021 15:23:24

Report to Moderator

Is there a way to modify the safety valve. I put a new valve in and the blade sinks after 4 min. It has 80 /90 w . I was thinking about putting a heavier spring on. The pump is clean and works very well. I spent a lot of time cleaning- scrubbed it with toothbrush. I put in a new relief valve . But I think it came from the land of dam near got her right.

[Log in to Reply]   [No Email]

02-22-2021 08:53:59

Report to Moderator
 Re: Safety relief 8n in reply to davyfireball, 02-21-2021 15:23:24  
Quoting Removed, click Modern View to see

Never a good idea to modify a relief/safety valve with out all the proper tools, specs and knowledge to change pressures. Not saying you don't posses all these, just that it can be dangerous. This should only be done on adjustable valves, which the 8N's hydraulic pump valve is not. Notice the crimp / stake or even solder holding the valve at it's correct pressure. Non-adjustable relief valves are typically set at the factory for the correct pressure for the application they're being used in.

There can be huge consequences of "winging" something with pressures like this, for safety reasons and mechanical damage.

Do a pressure test on your pump / valve. See if it releases at the required spec. If so, your leak down problem is likely elsewhere. If you can't build enough pressure to kick the relief valve open at spec, you have other problems. Only if the relief valve is found to be not working correctly should it be replaced. This is usually the valve being stuck open. Look for excessive turbulence at the valve. Don't confuse the PTO shaft turning with this. If by chance there was debris in the valve causing a leak, kicking the valve open with a pressure test would probably clear it.

Without knowing more about your capabilities, that's my recommendation.

[Log in to Reply]  [No Email]
Tim PloughNman Daley

02-22-2021 03:51:44

Report to Moderator
 Re: Safety relief 8n in reply to davyfireball, 02-21-2021 15:23:24  
Won't matter if cylinder and piston are worn and need replacing. I concur with Denny - the likely problem. Did you perform the Leak Down Test? Check oil -murky brown or whitish? Yes? Oil is contaminated with water. Can be from one or two things. Water sat in sump and then froze. When attempt was made to activate, pump may have cracked. Remove Inspection Covers. Start engine, run at idle, and engage pump. See bubbles at base of pump? Tat is the big clue. Leak Test: Attach a load like a rear blade or plow. Start engine, engage hydraulics, raise 3-PT lift to full UP quadrant, leave it UP, shut down engine. Using your Min-Mag flashlight, get on your knees and look up thru inspection covers to the hydraulic cylinder bolted on the bottom of the top cover under the seat. Watch closely and observe if oil is seeping/leaking down out the cylinder and piston. Yes? Cylinder is worn and possibly piston too and both need to replaced with NEW. Now is the time to rebuild the pump too. Clean and inspect all parts. The OEM N piston used three steel rings like your engine piston. When the NAA was issued, the hydraulic system used a new piston with a rubber O-Ring and a leather backup washer/wiper. This was a better piston and will also work on any N-Series. I highly recommend you don't think you can just hone out the cylinder and it'll work. It won't. Once grooves get worn in the cylinder wall, it will never seal. The job is not difficult, just time consuming to do it right and you don't want to have to pull the top cover a second time do you? Be aware that the 8N cylinder has a cast scallop at the 7 O'Clock position for clearance of the control rod. Many new aftermarket cylinders don't have this and you'll have to machine a scallop out yourself.

Tim Daley(MI)

[Log in to Reply]  [No Email]

02-21-2021 15:42:09

Report to Moderator
 Re: Safety relief 8n in reply to davyfireball, 02-21-2021 15:23:24  
It has new O ring and leather . The lift works so good with heavy snow it will bring the front of the tractor off the ground. Blade weighs close to 350 . And I have 80 lbs barbells on front.

[Log in to Reply]  [No Email]

02-21-2021 15:35:10

Report to Moderator
 Re: Safety relief 8n in reply to davyfireball, 02-21-2021 15:23:24  
Quoting Removed, click Modern View to seeOn such an old tractor,you should be proud of 4 minutes. What makes you think the safety valve is leaking?

[Log in to Reply]  [No Email]
denny k

02-21-2021 15:35:15

Report to Moderator
 Re: Safety relief 8n in reply to davyfireball, 02-21-2021 15:23:24  
In all probability, the seal in the lift piston needs replacing. If you remove the RH dipstick cover and raise the lift, shut off the pto and look inside for oil coming from the top cover. If so, the seals are leaking. There are new style seals and piston available from this site.

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

Hop to:

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

Today's Featured Article - Horsepower Defined - by Staff. Indicated Horsepower This represents the power developed in the enine cylinder as obtained from the pressure in the cylinders. This is pressure obtained from an indicator which shows cylinder pressures. Indicated horsepower does not represent the actual useful power delivered by the engine. Brake Horsepower This is the actual horse power delivered by the engine to the shaft. It is equal to the "indicated horsepower" less the friction of the engine. It is useful hor ... [Read Article]

Latest Ad: Looking for an original IH 730 Plow Operators Manual. Not interested in a CIH reprint. Thank you [More Ads]

Copyright © 1997-2021 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