International B-275 Draft Control Stuck?

[Bob Zerunkle]

Hello everyone,
This winter I purchased by first farm tractor, a 1960 B-275. I followed this with a running but really just-for-parts B-250. Preparing for this year I have changed all the fluids in the 275, replaced the PTO seal, upgraded the glow plugs and have learned quite a bit. Now I seem to be stuck, literally.
I just got a 5' bush hog thats worth more than the tractor. PTO clutch is slow going (same with transmission) and I am working on that and will probably end up making a seperate post for those interested in helping me out. But right now my problems lies with the 3 point hitch.
I am able to lift attachments just fine. However the 3 point hitch does slowly drop over time when it is holding weight. I am not sure of how common this is, but in reading I did learn about the draft control. It was working great to hold attachments at the height i wanted until it got stuck at the bottom. My 275 is equipped with the draft control dial. I had it spun all the way down when using a scraper blade to make garden rows. Now I cannot get it to turn back. In fact it will not turn at all. Even with the arms up all the way, I cannot get the dial to budge. It feels locked as if there is currently weight on it. I have downloaded the full service manual for my tractor and there is very limited information there to help me. Even in reading about the isolating valve, it is only represented in a diagram and not mentioned again. So pardon my ignorance, but does someone know if the isolating valve could effect these settings? Do I have to turn it to the right spot? I do not know where to go from here. I need to cut some fields and trying to readjust the bush hog height while trying to make turns up/down hills is just not going to cut it. I appreciate everyone's time.

 

[JimB2]

Hello Bob, welcome to YT, disclaimer, I have never worked on the old style draft control that you have on your B-275, only familiar with the newer style on B414 and beyond.
Do you have an Operator's Manual for B-275? I have original one from my Dad's early 1962 B414 that covers using old and new style draft control hydraulics.
Re Isolator Valve it should always be Fully OPEN except when using a remote hydraulic cylinder and you must understand how to use a remote hydraulic cylinder. Although the Operators Manual does recommend when transporting heavy 3pt equipment to lift the 3pt to desired height and then CLOSE the Isolating valve, we never did this procedure.
Leaking down 3pt with weight and engine off, usually is a leaky 3pt lift cylinder, there is a test for this.

Re Stuck Draft Control Knob, see phots below, threaded rod inside spring to adjust spring tension.
As you said. now you can't turn the knob at all, I would try with some with your bush hog on the 3pt, backup to a ditch with rear wheels higher up so bush hog can take the 3pt down to the maximum drop of the 3pt lift arms and see if you can turn Draft knob then. You may have to turn engine off so that the Draft system will allow the 3pt to drop to maximum down. Could try a tap with a rubber mallet on end of Draft control knob but not enough force to shear the pin through the knob and the shaft.

Good Luck
JimB

 

[Bob Zerunkle]

Awesome Jim thank you. I will give this a shot tomorrow.

 

[Bob Zerunkle]

Success! I dropped it down as low as it would go and tried the rubber mallet trick at different intervals. It ended up working when the arms were up all the way. It's entirely freed up and is working just like it did before. Thank you.
However the isolator valve does not seem to do anything on my 275. I can turn it either way and it never seems to stop. It could spin all day. It only becomes harder to turn when the tractor is running. The 3 point hitch and the loader seem to both work no matter where it is turned. I changed the hydraulic fluid this winter when I got the tractor, but I have not even acknowledged this valve until now. From what I understand its position is vital to whether or not I cause serious damage to the hydraulic system.
I also have a very beat up but running 250 that I have used for parts so far. It has the same hydraulic controls as the 275 but the isolator valve does open and close completely, and I know that it does function to control the 3 point hitch vs the loader because the owner before me demonstrated that to me. The 250 does not have the same hydraulic kit as the 275, it uses the original hydraulic control lever beside the seat to move up and down, and a manual trip on the bucket to drop dirt.
So my question is, is the isolator valve on my 275 broken or was it rendered this way at some point intentionally when the hydraulic kit was added on? The 250 is not likely going anywhere for a long time and if necessary I would be willing to drain the fluids and swap out that working isolator valve to my 275. I have included pics I just took now, the first few of the 275 I am using everyday, and then of the 250 that is parked. Thanks again, your insight and your time is really appreciated.

 

[JimB2]

Hi Bob, good news you freed up the Draft Control.
Re Isolator Valve, see photos below.
The Isolator Valve on the B250/275 tractors just Opens and Closes the Input to the 3pt Lift Cylinder, in Open position the high pressure oil from hydraulic pump flows into 3pt Lift Cylinder when Hydraulic Lift lever is raised, in the Closed position it forces the high pressure hydraulic oil out to what the British call the "External Jack Tapping" port and on your 275 that port has a pipe plug in it, so Closing the Isolator Valve and raising the Hydraulic Lift Lever will force the high pressure oil against the pipe plug causing a dangerous Hydraulic "Dead Heading" situation that can blow hydraulic pumps and the high pressure hydraulic lines. On you B250 this is where your loader receives it high pressure hydraulic oil from when the Isolator Valve is Closed.
The B275 has the loader connected properly so both loader and 3pt will work without changing Isolator Valve.

Re Isolator Valve parts, see second photo, I only see one O-ring and that is the sealing ring on the outer casting. I was expecting another O-ring on the end of the valve stem like a water tap.
My theory is that some previous owner forced the Isolator Valve and damaged the machined sealing end either on the valve stem or on the valve seat in the casting.
On your B275 there is nothing connected to the "External Jack Tapping" plug, so just turn Isolator Valve Open and leave it there OR you can let 3pt hitch down to lowest point, put the rear wheels in a ditch so that they are lower than the front wheels and with engine off, then the only hydraulic oil that should come out when you remove the Isolator Valve is the amount in the hydraulic line from the loader control valve to the input of the control valve in front of the seat.

Good Luck
JimB

 

[Bob Zerunkle]

Thanks again for the info Jim. The bit about limiting the hydraulic fluid loss if I change the isolator valve is golden. That is not something I would have ever figured out. With the depth control working I was able to get some real mowing done yesterday. Looking forward to learning more about the machines and getting some work done!
All the best,
Bob