3400 3 point hiccup

BigDanT · Mar 2, 2011

My 3400's 3 pt. lift wants to hiccup. I bought a cover kit and installed all new orings in the cover and on the lift piston also replaced filter and cleaned screen. I did all this before I read the post in Jan from Fordman1981, it sounds like his was doing the same thing as mine. Soundguy, I really like the idea of using a mirror to check for leaks, could you please explain how best to accomplish this? Do you do this with the lift cover in place and if so where do you get into the housing with the mirror?
Thanks

Soundguy · Mar 4, 2011

from the fill port. mind you that comment was based on a 53-64 series tractor that actually had fill ports in the lift cover you could peer in at. or an older model say 39-52 that had big inspection ports.

hiccups are either misadjustments in position control linkage, or leaks in the pressure side,of the lift circuit.. ie between check valve and lift piston.. though a leaky unloader might well make it bob/hunt as well. first place I usually look is the lift piston / cyl.. was the cyl ok?

soundguy

Soundguy · Mar 4, 2011

ps.. I don't mind saying that 65+ is getting out of my area of.. well.. i'm not an expert on anything.. but for conversational purposes.. lets say i'm much more familiar with the 39-64 models.. and much less familiar with the 65+ models.. though learning more every day...

soundguy

BigDanT · Mar 4, 2011

Ok thanks for the help anyway... the cylinder bore did have a slight score in it , I was hoping that the new o-ring might take care of that for a while, must not have. Any thoughts on a fix other than a new lift cylinder. Maybe honing the cylinder out and using a oversized o-ring? I've spent too much already rebuilding this thing and am trying to stop the bleeding but can't stand the thought of that lift not working just right.
Thanks

Soundguy · Mar 4, 2011

a scored cyl will eat a new ring very fast. I generally hone the cyl. genuine CNH orings are already pretty fat.. usually fatter than brands like tisco.

I honed my 8n lift cyl till it was actually JUST OUT of spec, and a CNH oring was still a mighty tight fit, and gave me rock solid hyds that stayed up, under load for 4 days.. 5th day started to droop a lil.

soundguy

Jbrink64 · Mar 5, 2011

Plug #15, seals the passage from the valve spool, to the cylinder. It is threaded to accept a slide hammer to remove it, meaning it must be tight in the bore. I have seen them loosen up, for some unknown reason, causing an internal leak.

BigDanT · Mar 5, 2011

I will try honing the cylinder and will buy a CNH oring...I tried to save a little with an aftermarket ring before, was a little afraid of it's quality. Jbrink, this may also be the culbrit, I missed the unload valve when I did the rebuild which means I also missed the seal (#14) I will check and replace these too. This will all have to wait a month or two, I have some clover I need to get sown, if it ever quits raining, but will get it done before the ol girl goes to paint this summer.
Thanks for all your help