8N hydraulics help

[AndyM]

I got home from work a little bit ago, and in the twilight glow, I decided to get the Ford 8N and do some box-blading.

After about 15 minutes, my three point arms quit lifting. My hydraulic oil level is fine, and now it's completely dark to try and figure out what's wrong. I've never had this problem before.

I'm not a mechanic, but I'm good at following directions.
Where do I begin looking?
What do I look at?
What am I looking for?

 

[beenthere]

You should get ahold of one of the repair books for the 8N.

I had a Ferguson TO-30 that did that, in the dead of winter at -20. I got it inside, and figured it was the pump. So grabbed the manual and started reading how to remove and repair the pump. First drain the oil. It was so cold, that it drained for two days.
After two days, I removed the pump according to the directions. When it was on my bench, I more carefully read the first line of the R&R section for the pump removal and it said something like "before removing the pump, remove the side covers and reach inside to see if a particular linkage was stuck or not. I grabbed the linkage on the pump sitting on my bench, and it was stuck, so I unstuck it. That's all I had to do. A five minute job had I read the first line. Instead I made it into a 5 day job. /forums/images/graemlins/crazy.gif

So, maybe that is all that is wrong, just a stuck lever going to the pump. The manual will give you some better information. Good luck.

 

[Soundguy]

This info is 8n specific.. if you have a 9n/2n or a NAA / jubilee / hundred series.. only some of it applies.

First.. pull right side cover.. This means you are removing the running board, and radious rod socket.

with the tractor running, and the pto engaged.. run the lift up using the hytrol lever.. Look for oil leaks on the inside. Oil from the mouth of the piston indicated bad rings or a bad cylinder... or a hole in the piston. Oil from around the cylinder means a bad dime shaped gasket between the cyl and the hyd top cover. Oil from the front right top side of the case means the top cover gasket has blown out on the inside letting fluid out of the standpipe. oil from the lower right front corner means the lower pump gasket has blown out letting oil out the bottom of the stand pipe. Oil from the pump sides means a cracked pump chamber, or one of the two chamber gaskets has blown. lots of oil swirling in front of the pump menas the check / relief valve has stuck open, or has blown out / unscrewed. If no oil leaks are present, make sure that when you move the hytrol lever, that the long arm that runs down to the hyd pump intake/exhaust valve is actually moving the valve into and out of the body of the pump.

If none of this helps.. you may need to drop the pump / pull the top cover. Always possible that a 50 cent cam follower pin has worn thru.. the hytrol lever has a pin on the inside which follows a metal contour that in turn moves that long control arm that goes down to the pump.

I just rebuilt the hyds on my 8n 2 months ago. Parts were less than 100 bucks shipped for all gaskets, new upgraded piston that uses a washer and oring instead of steel rings.. a new relief/check valve, side cover and pto gaskets.. etc. dowel rod, etc.. and a brake hone to resurface my cylinder. If I had bought the cyl.. that would have been another 80 bucks. Usually unless your cyl is completely gutted.. a hone works fine.

It's always possible that some of your draft linkage has come apart on the back side of the hytrol valve. I strongly suggest you get a copy of the I&T fo-4 manual.. it takes you thru the r&r of the pump, inculding torque values. Pretty much a 1 wrench job, as the pto bolts, side cover bolts, top cover bolts and bottom cover bolts are all the same size ( 11/16? or 9/16.. can't remember.. )

Don't use any gasket pucky on the top cover and bottom cover gaskets, as the hyd pressure at the front corner standpipe is 1700 psi.. and gaskets with pucky on them will blow out.. the thin paper is fine.

Gasket puckey however is fine on the pto gasket and side cover gasket.. though it doesn't need it. Don't use gasket pucky on the three small gaskets on top of the lift cyl either.. they go between the cyl and the top cover.

If you need part numbers, i have a sheet in front of me for what I ordered, and prices.. from www.just8ns.com.. pretty much the best prices.. and nice guys.

It took me 9.5 hours from driving the tractor in to driving it out of the garage. that included clean up time as this is a super oily / greasy job.

Refill with 4.5 gals of 90wt mineral oil gl-1.. tsc or napa has it. 134d oil from NH or unit-tran oil is ok.. but pretty thin. Fill oil till it drips out of one of the bottom holes on the inspection cover. This is plenty of oil for the tran/diffy/hyd pump, and keep oil from puddling around the axle seals in the mouth of the axle trumpets, and from setting on the tranny input seal... all 3 of those are prone to leak on a 50-60 year old machine.
That should consume a little over 4 gallons of your 5 gallon pail of oil. Don't use 80w90 gl-5 oils.. the gl-5 oil is known to have compounds which can damage yellow metal.. and the cam blocksin your pump are yellow metal.

I did mine over a long 3 day weekend.. if you can work on it 1 day straight.. figure 8.5 hours if you stick to it.

Only tricky part is getting the long arm from the top cover lined back up in the slot on the valve inthe pump. Top cover weighs? 65pounds. bottom pump weights 40?

Soundguy

 

[AndyM]

Thanks Sound-dude... I had a feeling you would reply! /forums/images/graemlins/cool.gif

I'm sure it's something simple, but it's a matter of finding some extra time to even look at it, let alone fixing it. /forums/images/graemlins/frown.gif

I still don't have a building, and Mrs AndyM won't let the 8N into the garage. /forums/images/graemlins/crazy.gif

Good day!

 

[Soundguy]

If you just need cover to work on it outside.. go grab one of those el-cheapo 'lunch' pavilion tents. Theye are usually 8x8 with 4 metal legs and some kind of decorative trap top. I got one for the wife at the beach from eckerds for 19 bucks.

For that matter.. a tarp works fine.. Just use newspaper to tape off any exposed areas.. like the top and bottom case of the hyd section..

If you do drop the pump, I reccomend getting a few gallons of diesel or mineral spirits.. whatevers cheapest.. and a spray bottle or garden sprayer, and rinse the sides of the sump out. Also not a bad idea to spray off the pump as well. I set mine in a big oil change pan,. and tilted it up by setting it on a big bolt.. then sprayed off the 50 years of crud that settles to the bottom near the pickup of the pump.. under the drain plug.

You can even use your hose to spray the pump out.. just go back with mineral spirits or wd/40 to 'wash' it down.

When you pull the side cover for diagnosis.. email me if you need any help.

Soundguy