8N 3PT not raising high enough?

[BossofBBQ]

Hey Folks,
I'm back again with (I hope) a simpler question than last time...
I don't think my 8N's 3 point is raising high enough. Measured at the link balls (at the very end of the lift arms) , it only raises to 25 inches. I can manually lift the entire 3pt mechanism for another 7 or so inches above that. If I lower the hitch all the way down, the link balls drop to only 4 inches above the ground. The only thing stopping them from going lower is the leveling box hitting the axle casting.

The hydraulics seem strong. It lifted my 6' Ford disc fine, but couldn't get it fully off the ground because that would mean lifting past the 25" mark.

Is there a way to adjust the hydraulic travel/range of motion?

 

[RayIN]

That kinda sounds like the relief/overpressure valve is bad on the hyd pump.

 

[Roadworthy]

See if there's a stop on the lever that operates the three point. Many tractors have them to set upper and lower limits on the three point. I use mine to limit the lowering point of my mower so it doesn't drag.

 

[EdGooding]

Hey Folks,
I'm back again with (I hope) a simpler question than last time...
I don't think my 8N's 3 point is raising high enough. Measured at the link balls (at the very end of the lift arms) , it only raises to 25 inches. I can manually lift the entire 3pt mechanism for another 7 or so inches above that. If I lower the hitch all the way down, the link balls drop to only 4 inches above the ground. The only thing stopping them from going lower is the leveling box hitting the axle casting.

The hydraulics seem strong. It lifted my 6' Ford disc fine, but couldn't get it fully off the ground because that would mean lifting past the 25" mark.

Is there a way to adjust the hydraulic travel/range of motion?

Your range of motion should be closer to 8" at the lowest and 33-34" at the highest. This assumes you have 28" rear wheels.

You may be looking at an overhaul of your top cover. Do you have any manuals?

 

[John0829]

Ed gave you the proper measurements, more likely than not someone put the lift arms back on it the wrong position when doing an R&R of the top cover. As for the free travel at the top of the lift, you will have some due to how the hydraulic cylinder is connected to the lift arms using the dog bone link.

 

[BossofBBQ]

Ed- my tractor has the 28" wheels, and I just recently obtained all the manuals: I&T FO4 service manual, Owners manual, and a master parts catalog/assembly manual.

I was out fiddling around with my middle buster/potato plow today, and made an interesting discovery: the 3pt won't raise at all when in "draft control" mode. When this happens, the lever under the seat is fully horizontal. But, if I continue to apply moderate downward pressure to it with my hand, my 3pt will raise to a full 34" and function correctly. When I stop manually holding the "draft control" lever down, I lose all hydraulic power. The lever is still horizontal at this time. If I switch the lever vertical (Position control), the arms only raise 25" above the ground.

I am running fresh TSC Traveller Brand UTF and the level is right up to the "full" mark on the dipstick.
Roadworthy- my tractor does not have a nifty stop on the adjuster lever, so there's nothing to restrict movement there.

I know these problems are difficult to diagnose online, but I couldn't seem to find any symptoms that match mine in the manuals. Something is obviously worn/broken internally, but how would I go about pinpointing the issue?

 

[EdGooding]

Ed- my tractor has the 28" wheels, and I just recently obtained all the manuals: I&T FO4 service manual, Owners manual, and a master parts catalog/assembly manual.

I was out fiddling around with my middle buster/potato plow today, and made an interesting discovery: the 3pt won't raise at all when in "draft control" mode. When this happens, the lever under the seat is fully horizontal. But, if I continue to apply moderate downward pressure to it with my hand, my 3pt will raise to a full 34" and function correctly. When I stop manually holding the "draft control" lever down, I lose all hydraulic power. The lever is still horizontal at this time. If I switch the lever vertical (Position control), the arms only raise 25" above the ground.

I am running fresh TSC Traveller Brand UTF and the level is right up to the "full" mark on the dipstick.
Roadworthy- my tractor does not have a nifty stop on the adjuster lever, so there's nothing to restrict movement there.

I know these problems are difficult to diagnose online, but I couldn't seem to find any symptoms that match mine in the manuals. Something is obviously worn/broken internally, but how would I go about pinpointing the issue?

I think you are headed towards removing your top cover behind the seat and going through it to check for worn parts and make the right adjustments. I'll be interested to see if John in KY agrees. If he does, then the FO4 gives the procedure. I can also send you supplementary info from Ford Tractor that gives more details on the procedure. The FO4 kinda assumes you know how to do the tasks, so it just tells you what to do. I have a copy of the Ford Tractor 8N Mechanic Training Manual, and it gives more details on how to do the steps. Holler at me (that's Virginia and Kentucky talk ) if you want it.

There are some good YouTube videos on this process. This is a good one:

Rachel knows her stuff.

You can even buy a tool to make the adjustments easier to get it right the first time: LG500-LG500 Years:1939-52 Lift Jig

 

[John0829]

I am 100% with Ed on this, sounds like you need to do an R&R on the linkages. It sounds like someone may have, at some point, used the wrong hole on the top link rocker causing it to bend the linkages inside the cover. The top hole is for implements needing a "light" draft, think cultivator, where the bottom hole is for heavy draft implements, think plow. Most the owners of the 8N tractors today do not know this and slap the top link in the top hole because, well, it's handier/easier to get at.

At the very least I would expect the cam follower pin to be worn out and possibly some wear on the cam as well since they never get any lubrication in spite of being in a housing full of oil.

So it is worth popping the top for a look see.

 

[BossofBBQ]

The uppermost hole in the top link bracket is pretty oblong. I’ve always used the lowest one, but obviously the previous owner didn’t. I’ll look into pulling the top cover, but I don’t have access to a chain hoist or cherry picker right now, and currently only have an open-sided equipment shed to work out of.

Ed- I’d be very grateful to get a look at the Ford 8N Mechanic Training Manual. I’m new to N series tractors and I’m learning lots everyday…

 

[EdGooding]

The uppermost hole in the top link bracket is pretty oblong. I’ve always used the lowest one, but obviously the previous owner didn’t. I’ll look into pulling the top cover, but I don’t have access to a chain hoist or cherry picker right now, and currently only have an open-sided equipment shed to work out of.

Ed- I’d be very grateful to get a look at the Ford 8N Mechanic Training Manual. I’m new to N series tractors and I’m learning lots everyday…

You only use the top hole for light cultivation tasks. He obviously has hosed the draft control linkage up by doing that. A chain hoist/cherry picker is nice, but one reasonably strong man can handle it easily. You may need a BF pry bar to break the cover loose once you remove the bolts.

 

[EdGooding]

If you overhaul your top cover, I highly recommend using a piston from the later NAA model instead of the 8N piston. It's been proven to last much longer and scar the cylinder up less. If you watch that video, Rachel talks about it.
Also, before you start on the job, buy a cam follower pin. They are usually pretty worn. If you can't find a new one, and the existing one has a flat worn on it, you can extract it and insert the crappy end into the hole and have a whole cam again.

It looks like Steiner Tractors has them in stock for $5: https://www.steinertractor.com/FDS3403-Inner-Hydraulic-Lift-Control-Rod-Pin#checkFitScroll

 

[John0829]

Or you can use the shank of a proper sized drill bit for the cam follower pin, I do. But many do not like it for they think it will wear out the cam more quickly, and I guess it might, so far I have had no issues doing it. If the cam is found to be worn it can be built up by someone using a torch and bronze rods.

 

[BossofBBQ]

Thanks for the photos Ed! I have them saved off and stored with my service records. I'll pull the top cover next weekend when I have some spare time. What am I looking for once the cover is off? Bent linkages I assume? I watched Rachel's video and will most likely end up rebuilding the top cover with a NAA piston. I will order a cam follower pin accordingly.

 

[EdGooding]

Thanks for the photos Ed! I have them saved off and stored with my service records. I'll pull the top cover next weekend when I have some spare time. What am I looking for once the cover is off? Bent linkages I assume? I watched Rachel's video and will most likely end up rebuilding the top cover with a NAA piston. I will order a cam follower pin accordingly.

Once you get the cover off, replacing the piston/cylinder and cam follower pin are often the only parts you need to replace. Look for any other parts that look broken or not right. The former owner clearly abused the draft control system, so you may find some linkage damage. After that, it comes down to making the proper adjustments for both the draft and position control functions. That's why I pointed out the jig for this. You can buy it, use it, and then sell it on eBay and get most of your money back. I have a variation of this jig that I got years ago from Zane Sherman. I've attached the instructions for it because they have some good inside-baseball tips for this task.

 

[BossofBBQ]

I'll plan on getting the jig too- I can imagine that it would save a lot of time/effort in getting the adjustments right the first time.

Another thing I noticed- when lifting heavy implements, the pump makes a "clunking" noise. It seems to be strong, and has no problem lifting disc harrows and boxblades. It just can't get them very high off the ground because the range of motion is so limited. Is the clunking/knocking normal, or should I plan on a pump rebuild as well?

I'll pull the top cover off this weekend and report back with my findings.

 

[EdGooding]

I'll plan on getting the jig too- I can imagine that it would save a lot of time/effort in getting the adjustments right the first time.

Another thing I noticed- when lifting heavy implements, the pump makes a "clunking" noise. It seems to be strong, and has no problem lifting disc harrows and boxblades. It just can't get them very high off the ground because the range of motion is so limited. Is the clunking/knocking normal, or should I plan on a pump rebuild as well?

I'll pull the top cover off this weekend and report back with my findings.

The clunking noise is coming from your pump and does indicate wear in the scotch yokes. However, folks have used them for years with that noise. Once you get your top cover right, and if the lift works as it should, I would probably put up with the noise. The true test of your pump is to pressure test it. There is a port on the right side of the pump where you can attach a pressure gauge. After you deal with your top cover, and if you want to do this, I can share some instructions.

 

[BossofBBQ]

I got the top cover off today, and got a good look at the internals. I disassembled the cylinder/piston, following Rachel’s video and the Ford Tractor mechanic instructions. My piston and cylinder are both very badly scoured and will need to be replaced. I didn’t see any obviously bent or broken linkages, and the cam follower pin, while worn, wasn’t as bad as I thought it would be. I’ve attached some photos below- maybe I missed something. I’ve never had an 8N apart before, so I’m learning as I go.

I tried to remove the draft control spring, but I don’t think my little handheld plumbing torch could get it hot enough to free up. I stopped trying for fear of breaking something. It’s currently soaking in some penetrating oil. Do I need to remove the spring to be sure the linkages are intact?

I’ll plan to order a master rebuild kit, along with a cam follower pin and the adjuster jig from Just8Ns.

 

[BossofBBQ]

Update: got my top cover reassembled yesterday, and everything is working like it should. I now have 32” of lift height at the end of the arms. Thanks again for sharing the Ford Tractor mechanic instructions, Ed.

 

[EdGooding]

Update: got my top cover reassembled yesterday, and everything is working like it should. I now have 32” of lift height at the end of the arms. Thanks again for sharing the Ford Tractor mechanic instructions, Ed.

Thank you for closing the loop and letting everyone know the solution to your problem and the outcome of your repair work.