8N Hydraulic Pump?

[tderrick]

The 8N is having difficulty lifting the bushhog off the ground lately. What could be some things to try, short of a complete pump overhaul?

thx

 

[gary49]

Might just need the lift cylinder rebuilt. The 8N's were designed to be worked on by farmers, it's not so hard. Parts still easy to get and not expensive, get a manual and have a go at it.

 

[tderrick]

Might just need the lift cylinder rebuilt. The 8N's were designed to be worked on by farmers, it's not so hard. Parts still easy to get and not expensive, get a manual and have a go at it.

I think I'll try that over the Winter. Would that be the first / easiest thing to check / rebuild?

 

[gary49]

Pretty easy, I think. I’ll admit I haven’t done an 8n , but replacing the seal in my Fordson was not hard. You get an opportunity to drain the old oil and you can get rid of any water that has gotten in there, which is a good thing to do in any case. Also easy to remove the pump and inspect it while you’re in there.

 

[tderrick]

Pretty easy, I think. I’ll admit I haven’t done an 8n , but replacing the seal in my Fordson was not hard. You get an opportunity to drain the old oil and you can get rid of any water that has gotten in there, which is a good thing to do in any case. Also easy to remove the pump and inspect it while you’re in there.

Thx for the help, brother... One more question - Do you know a line on any good shop / tear down manuals to help me?

 

[Barry 1]

Look up N Tractor Club

 

[Wilburdog]

The I&T shop manual provides descent information of the Ford 8N.

I agree the N Tractor Club site is a very good reference.

As well John Smith’s site has great info but I believe he retired his site but the info may linked to another Ford tractor site.

A couple things I did when the hydraulic lift was leaking down on my 8N was remove the round cover inspection plate on the right side (when sitting in seat) of rear housing & observe if fluid is spraying from a specific location internally. In my case the leather ring seal around the lift cylinder piston was worn. I upgraded to a NAA piston & seal kit plus very lightly honed the cylinder.

Another thing to check for is a defective pressure relief valve. This is located at the base of the pump inside the rear housing. Look for fluid leaking in this location.

As well confirm the condition of the transmission/gear oil. It may be contaminated with water.

I ended up dropping the hydraulic pump just because I want to learn how it worked. I disassembled, cleaned the components & resembled. Upon disassembly I could a piece of wood lodged in one of the check valves. Lots of sludge accumulation was cleaned out of the pump & rear housing that most likely helped improve pump operation.

Once refilled with universal tractor fluid the hydraulics has been working great for several years now.

My resources were: the I&T Manual, a old Ford 8N shop manual, the N Tractor Club site & John Smith’s site.

Hope this helps.

 

[mapper]

Make sure you have permatex form a gasket on hand to stick the hydraulic pump gasket in place when reinstalling the pump. You have to lift the pump up then slide it forward about a half inch when it's about a eighth of an inch away. Keeping the gasket in place is almost impossible, and since the high pressure oil flows up to the lift cylinder through a port in the base plate into the transmission case any displacement or inadequate torque on the bolts results in 90 weight oil spraying out between the base plate and transmission case.
Go ahead, ask me how I know this:laughing:

 

[tderrick]

Thanks for all the help guys. I did pick up the I & T manual and the original 8N manual. Will get it in the garage this winter and will work on it on the
weekends.

 

[Soundguy]

Make sure you have permatex form a gasket on hand to stick the hydraulic pump gasket in place when reinstalling the pump. You have to lift the pump up then slide it forward about a half inch when it's about a eighth of an inch away. Keeping the gasket in place is almost impossible, and since the high pressure oil flows up to the lift cylinder through a port in the base plate into the transmission case any displacement or inadequate torque on the bolts results in 90 weight oil spraying out between the base plate and transmission case.
Go ahead, ask me how I know this:laughing:

that permatex, if it's anywhere near the pressure port is a pretty much guarantee to make the paper gasket blow out. plain grease works better. you DO NOT want any rtv or goop on those paper thin, paper gaskets that go in the hyd system on an N