806 locking brake issue..Long...need help...still

Wheels turn freely when tractor is NOT running, start tractor and (both)brakes instantly are locked. So far I have, went though brake's replaced pads, and did replaced orings and seal in one(right side). Rebuild brake valve assy, reassmebled according to IT, set brakes adj according to IT manual. Moved upstream to Master control valve(?), removed and inspected the pressure regulator (?) valve? Top valve spring assm on the rear facing side of the Master valve block. Found nothing wrong, even took the one from another tractor and tried it, I have aslso swapped the brake valve assy with a known good one. What the heck am I missing, the IT manual doesnt go any more in depth to trouble shoot, the local mechanic at the dealership didnt seem to know. Is that top spring assemly even the right one to look at? It just seems that as soon as the tractor is started, the brakes valve get too much pressure, is that possible? I take brake valve and put on another tracotr and it works fine. I'm at a loss, please help? Is the bypass valve related to the brake supply pressure? As a side note, the power steering on the tractor doesnt seem to be the easiest, if that could be related at all.

Is there any other "brake" on the 06's that could be giving me trouble, like a hyraulic tranny brake or some thing?

I don't know anything about the brakes on those tractors, but just a thought would be to give Timmer's Implement a call in Pease, MN. They do seem to have knowledgeable mechanics and parts men that work there. Wes in the parts department is very knowledgeable, and if he doesn't know, he'll get a mechanic on the line and they have always had an answer that I was needing.

No All i can say since I am not maken a service call that far out is ya really need to get a pressure gauge on it first off and also check the return line off the brake to the sump. The check valve may be in backwards or the line is plugged or crimped off . In all the 06-86 tractors that i have worked on this is new to me . . I have never had one do anything like that BUT there is always a first .

The only other brake is mechanical. It's the lever or pedal (rare) below the shift quadrant and above and to the left of the brake pedals. When engaged, the tractor is locked whether the engine is on or off.
Some European tractors had hydraulic trailer brake attachments but there would be a lot of extra plumbing on the tractor.

The steering effort is probably a clue. but I'm in over my head. Second Timmers.
There also are some good independent guys throughout the state too. I know of 2 about 25 miles east of St. Cloud.

good luck

karl f

do you have a cab or customized platform?
Have you made sure the spools return all the way when the pedals are against the platform?
throwin out ideas...
karl f

never experienced this one... but first thing i would do is pull that return line from the power brake valve and make sure oil comes out when you start up the tractor. also maybe put the air hose to the tractor end and make sure it"s a clear run into the reservoir. don"t know if a blocked dump line would cause your symptoms but.

i forget, is this a problem that just suddenly started? or new to you tractor? what else has happened to the tractor since it worked right?

I just bought it last fall, brakes have dragged since I bought it. Had mechanic work on it , he rebuild the brake valve and assumed it was fixed, Havent really used it much since, but you could always tell brakes were dragging, hard. The tractor is a T/A delete, the reared is off a 706, not sure when that was done. Also, it was dropped off at the mechanic initailly when I bought it to have a heavy duty clutch put in, when we went to pick it up is when we noticed the brakes dragged, not sure if they were dragging prior or not.