3 point on farmpro drops

[nvnenzel]

New to this whole thing but this looks like the place for help.
I have a Farm Pro 2425 which I understand is a Jinma 254 knockoff. The tractor has just 67 hours on it, guy bought it and it was too small for his construction business. It does a great job for what I need but the three point drops no matter what I do, even if I don't have the box plow attached. I've closed the 'knob' under the seat but then I can't get it to raise. If the engine is running I can't even turn the knob to control the attachment raise lower speed, but turning the knob doesn't seem to stop the drop anyway. I have a small leak in the raise/lower valve but the attachment seems to drop more quickly than that small leak would justify, but of course I could be completely wrong. I guess my first question is where do I start. I've seen the posts on blowing air through the lines to see if I get a 'gurgle' bypassing the main cylinder, but at what point in the line etc. I have the original manual but it reads like an english translation from chinese by a half blind baboon. (for instance, after adjustment has been spared length resolve to rotate lock for safety to operator.)

 

[bluechip]

You probably need to replace the O ring and wiper on the piston in the lift box. We have the kit in stock, as to most Jinma parts dealers.

 

[RonMar]

Yep, sounds like a piston "O" ring, if it drops with the speed reg valve screwed all the way down/closed. That speed valve is between the control valve and the cylinder and should separate the two parts. If you can screw it all the way closed, and the valve will no longer lift the 3PH, then you know that the valve is sealing OK.

There should be a diagram in the manual, but in case you don't have it, here is a link to one on John's jinma website
http://johnstractor.homestead.com/files/HydPowerLift.jpg

If you drain the hydraulic reservoir, and remove the rear cover plate where the toplink attaches(hydro reservoir drainplug is at the lower left corner of that toplink plate) and the 4 bolts around the front plate of the cylinder, the whole cylinder and the piston should come out the front. I guess sometimes the piston can overtravel and go too far out of the end of the cylinder and allow the "O" rings to be damaged by the rear cylinder lip. There is supposed to be an end stop on the inside of the rear cover plate(part 42 on the linked diagram) but I guess these aren't always set up correctly. There is also a linkage rod from the lift arm on the right side of the tractor back to the control valve. That rod closes the lift valve at the top of the lift. If this is not setup correctly, this will also allow the piston to travel too far. This will also be an excellent opportunity to flush out the shavings you will fing spread across the bottom cavities of the hydraulic reservoir

Oh, and it is generally considered poor form to post the same question in multiple locations...

Good Luck

 

[Affordable]

The 3-point needs to be rebuilt as stated above, it's not a hard task to do,just a little messy.We can help you with the kit and it's installation

Tommy
Affordable Tractor Sales Co.
Home of compact Jinma, Foton, and Koyker Tractors and Parts, Wood Chippers, Backhoes - Affordable Tractor Sales Company

 

[nvnenzel]

Thanks everyone, what RonMar said and looking at the diagram makes sense. Since my manual is so poorly written trying to decipher anything from those pages is a waste of effort, thanks for the diagram. I'm going to pull the piece apart in a few days, still gotta work, and at that time I'll check the rings and order a new set. I'm sure they are bad from all you've written.

BTW, Ron, I agree it's bad to post several places. I posted first in the hydralic section and an astute person there recommended I come to this part of the board. It was, to be certain, sound advice.

 

[RonMar]

BTW, Ron, I agree it's bad to post several places. I posted first in the hydralic section and an astute person there recommended I come to this part of the board. It was, to be certain, sound advice.

You know, I didn't even read the one up in the hydro forum, I just saw it as I scanned the subjects there, then saw it again here, and assumed the worst from a new poster(sorry, bad habit of mine). If you get a chance, explore John's jinma site, he has a lot of fantastic information on these tractors all in one place, such as all the manual exploded views for the tractor and the engine. He also has quite a few usefull modifications documented there. I refer to his site quite often when looking for answers.

 

[jaroban]

I had the same problem twice . The rod mentioned above was extended out too far and when you lifted all the way up the seal on the main piston would fail. I adjusted it so that would not happen again and then cut off the extra length on the rod. Get some gasket material before youstart.Good luck Robby