Park brake won't release.

Hey working on my 963 caterpillar track loader. Ser# 18Z01382 I believe its 1989. I am trying to figure out if this machine has a electric brake switch somewhere or brake solenoid. Does anyone have a wiring diagram on this? Or hydraulic schematics?

you do not have a parking brake switch if you’ll notice the little notch at front of transmission v says park What is the tractor doing

I am not getting any hydraulic pressure to the brakes when I put in gear.

First make sure center pedal is up the whole way second under the cab there is a lever on valve linkage goes to brake pedal on the side of this lever should be a hole for a 5/16 bolt if brake lever is in proper location a 5/16 course bolt will screw in also note brakes will not release unless there is a movement towards wider part of v every thing on this transmission is mechanical or hydro mechanical

Let me try this. Thank you

One other important thing if the cab is tilted brakes will be applied

I did the 5/16 bolt on the brake lever. And no difference

Ok was it going slow and did you have to pull transmission lever way back for it to move? When it would move

Only issue this machine had was it would always track to the left. All I did was lift the cab. Took the cover off on top of the transmission. Also took the left side drive motor off took it apart looking for wear and put everything back together and it never moved after that.

Ok first theres a pressure tap on top of motor I would put a 600 pound gage on it first take pressure at full throttle and all the way back in drive One other important step it would probably be a good thing to lock the brakes there will be a line coming from valve where leaver is going to column there will be either a square block with steel lines coming out of it or a pump assembly with a u tube either way plug the line coming from transmission it is a jic line

You brought back old memories I had to go look at serial number this thing made me and a cat engineer pretty near crazy it’s serial was 48z

What in the world did they do with that thing? Smash stuff?

They were towing basically a box grader the counter weights were to hold front end down. That thing would go about 150 feet and hang a left on it's own every time it went to 150 foot as long as you didn't go that far it ran straight as a arrow

What was the hang up then?

Never really find a smoking gun cat had me change the c&r valves, did all the adjustment many times swapped drive hoses checked every pressure on it. Finally changed the whole hpcu and fixed the problem. lot of things will cause a slight drift one way or another but that one was like you pushed the steer pedal to the floor at 150 foot and it would do it every time you made a run to 150 foot

Damn computers!

HarleyHappy said: Damn computers! Click to expand... None of those on the machines in question here