TD-9 dozer hydraulic pressure

[plowhog]

I am getting a 1950's vintage International TD-9 crawler back in operating form. Right now I can run it on gas then diesel, and I can operate it in forward and reverse.

Initially, with the engine at RPM, the control lever to raise the front blade did nothing except make a lot of chatter/vibration. Pull the lever, nothing happened except chatter/vibration. The system was a gallon low on hydraulic fluid so I fixed that. But still no change in operation.

A few days later I added a psi gauge. I heard a small gurgle gurgle when I removed the plug where the gauge now is installed. Now, when I pull the lever to operate the front blade, the blade does rise and I'm showing about 500psi pressure. It does rise slowly, but not too bad. When I release the lever or move into the blade down position, the pressure is at zero.

I don't know what is causing the buzzing/chatter when I operate the lever. Does anyone know about what operating pressure I should be seeing? 500psi seems low?

 

[wvgca]

Not really, the TD9 used a low pressure pump, fairly high volume though ... I USED to have the same one, but no longer do, and I think the pressure was a maximu of 600 psi ....
I now run a 1945 Cat D4, again a fairly low pressure system, with 3/4 inch hoses though ..Maybe check the hydraulic filter on the TD9 ?? It could be partially plugged ...

 

[plowhog]

Thanks I will check that.

 

[CADplans]

Now, when I pull the lever to operate the front blade, the blade does rise and I'm showing about 500psi pressure. It does rise slowly, but not too bad. When I release the lever or move into the blade down position, the pressure is at zero.

My sister purchased a TD9 about the same vintage as yours,, in the 1970's,,

If I remember correctly, the hydraulics is a simple "open center" system.
The pump only makes pressure when the valve is moved, and the oil is doing work, such as lifting the blade.

When the valve is centered, the pressure should be near zero, it is doing no work, other than overcoming friction of the oil in the lines.

The "chatter" is possibly the vane pump doing what it does normally,, chattering when it has to work.

I owned two machines with vane pumps,, that chatter is pretty normal,, that is assuming the pump is a vane type,,,

 

[plowhog]

Not really, the TD9 used a low pressure pump, fairly high volume though ... I USED to have the same one, but no longer do, and I think the pressure was a maximu of 600 psi ....

Yes, when the valve is centered the pressure is zero. Engage the valve such as to lift the blade and it immediately goes to 500-600psi.

I just had some new hoses made. I asked the person in the hydraulic shop what kind of fluid he thinks I should be using. He said: "based on something that old (1950's) the only fluid I would run in it is AW46."

But, to the contrary, the barn where this dozer has "lived" for decades has many pails of AW32, and Chevron 1000 THF fluid. A few new ones and many empties. There is another vintage tractor on the property, but I am guessing these were used in the TD-9 in the past. Part of rehabbing the TD-9 back into operating condition was to top off all the fluids, and I did add several gallons of AW32 before firing it up. Now I'm wondering if that was too thin, and might be responsible for some of the valve chatter?

There are no manuals. I'm going to have to guess on what to add. So far I am guessing AW46. What would you guess?

 

[wvgca]

I used to have some books on the TD9, just they are not handy, lol ..
AW46 should be good for summer and a little bit of frost on the ground ... if you are not going to use it below freezing, then you can even go a grade thicker ...
I wouldn't worry about the valve chatter, ..

 

[plowhog]

I bought a TD-9 service manual online, but it had nothing at all regarding a hydraulic pump. I'm not sure why.

This TD-9 has a Kellogg Model AP10V-7 hydraulic pump. It is an older aviation pump formerly used on commercial jets. Which makes sense as the former owner was a commercial pilot and there are many aircraft stainless lines in place of hydraulic hoses.

On the pump data plate, it calls for Skydrol 500 fluid, which is a fire resistant aviation hydraulic fluid. Sounds like hazardous nasty stuff as well.

I have no idea of the Skydrol viscosity compared to typical tractor fluids?

Skydrol - Wikipedia

 

[wvgca]

I thought your issue was slight valve chattering ... this has nothing to do with the pump, lol

 

[plowhog]

I don't know why the valve is chattering. As written above, it might be normal, or perhaps not. So I was wanting to sort out what hydraulic fluid to put in after replacing some hoses and parts.

fyi I was looking at the pump to see if it had a recommended fluid on a data plate, which it did. But I don't know anything about the fluid it was recommending. So I'm still on track to add AW46.

I very much appreciate the assistance!

 

[Sonny580]

At one time I had 4 of the 9's ---- all 4 had bad hydraulic pumps on them ---- ended up putting a front mount pump off of a wagner backhoe on it and ran hy-tran in it ---- never had a problem after that and had to watch not to pry too hard with the blade----did blow a couple hoses. Backhoe pump ran the standard 2,500 to 3,000 pressure and made a whole different dozer out of the last one I had.
You could do some serious work with it---blade was snappy on the lift/lower so you could fine grade with it.