Hello to all, my first post after reading for a few months, I’ll try to keep this post shorter than a novel. I’ve been following a thread by Don Shilling documenting his clutch rebuild on his Komatsu. While it furnished me with loads of info, my problems were not fixed when my clutch rebuild was completed. The dozer I’m working on is a 1985 Komatsu D31p-16. My Uncle bought this dozer from a neighbor who rebuilt the motor, and he did a great job of that. But he lacked in further ambition to repair the other problems. The left steering was always sketchy, the foot pedal would stick before full return and only turned using the brake. The right side seemed to be functioning properly, full pedal return and quick to release the clutch. I am a mechanic of sorts but never did any serious work on a dozer. Anyway I got called to the front line by the family and here I am. Using Dons great thread and the repair manual, ( horrible pictures) I got the left clutch out and discovered the yoke bearing was in pieces. So I replaced the yoke bearing and installed new clutch plates and discs. Put it back together and went to investigating the sticky pedal. Found all the pivot point bushings completely worn out. Resolved that mess and finally after months of research, greasy hands and cold feet I fired up machine only to find the the steering was still whacky and now on both sides. Everyone here knows that feeling, que the non stop analyzing and ceiling staring at night. Whew, after re-living that I have to go lay down. Ok now after that bit of history, my question. Even though the machine moves forward and backwards perfectly, is it possible that the screen filter in the hydro shift transmission needs cleaning? Sounds too easy but one can hope. The steering valve in front of dash seems a possibility also, not so easy or cheap. I did adjust the yoke bolt that the ram moves to disengage clutch. But the machine moves only slightly when I push in pedal. Thanks, Jb
You need to put a gauge on it to see if you have proper pressure sounds like a steering valve problem a gauge will tell you if the valve is working I done a d65 and had to pull valve and found a little piece of trash in it
I got a gauge just yesterday and checked pressure at both disengagement pistons. Both showed pressure of 270psi. My manual shows proper pressure between 242-327psi. I had a friend watch the gauge and tell me when it showed pressure. Both showed that 270psi with minimum movement on the pedals, so the pressure seems sufficient which leaves me still struggling for an answer to the weak steering.
While helping me with the pressure readings on the clutch my buddy asked why the rods to the brakes were not hooked up. A good question to ask no doubt. I replied that I was concentrating on the linkage to the steering valve first and would then hook up the brake rods and adjust them. He says don’t you have to have the brakes to turn? I said yes but only for major turns not minor moves. Am I correct here...a person shouldn’t have to engage the brake to turn when tramming a dozer down a road, which is what this machine does, I had to engage the brake to make small turns while tramming it down the road. I try to fix stuff, I’m not a dozer mechanic or an operator so forgive my lack of knowledge.
If you are under a load or going up hill it will turn without brakes but generally you need to brake hook up brakes
Thank you Dave for that info. I thought the opposite, that releasing the clutch with no load would steer and the brake would only have to be engaged to help adjust the dozer direction while moving dirt.
Machine has to have a little bit of load to turn. That can be going up a hill, some dirt with the blade on the ground or some amount of brake applied. The brake adjustment can affect the steering clutch adjustment if you have a compound linkage that releases the clutch and applies the brake.
Thanks for the info, over the years I’ve had sit time on a few JD 450 dozers but could never claim to be an operator of any level but amateur. I did figure out my steering problem. Turns out I failed to get the left side brake linkage under the clutch cover fully in place, and the right side brake was out of adjustment. After pulling the cover and properly fitting the linkage to the left brake band and adjusting both brakes it turns like butter. Now a pleasure to use as before it was a nightmare. I still have a hard time steering with pedals instead of levers. The last thing I need to repair is the left clutch release piston. It’s leaking oil into the clutch chamber and I need to replace o-rings. Anybody know how that piston comes out of the case? Thanks Jb
Unhook the hydraulic hose, remove the cylinder, then use an air nozzle and GENTLY apply slight air pressure to the hydraulic fitting.
Ok, thanks for the info Don.
Good morning, I found this post while researching a problem with a project dozer I have. I recently bought a D31A that wasn’t steering. I have struggled with getting the clutch cover/brake assembly installed correctly, and sounds the same as your issue above. I am thinking my steering valve is the biggest issue. I have pressure coming from the transmission, but nothing coming back on the return, or to either clutch piston. I am hoping for a piece of dirt blocking the input side, but hard to say. Any suggestions are appreciated! Thanks
I worked on one that had a tiny piece of metal in the valve and that was the problem
Thanks Dave. I hope I find something similar. I can’t see there’s much inside the valve to fail by the diagram.
No it is simple
Thanks again for your help Dave. Took apart the steering valve, and after a thorough cleaning and linkage adjustment, she is working great! For the D31A-16, can anyone point me in the right direction for types of fluids? I do not yet have a manual for this machine. I read somewhere that the transmission, hydraulics, final drives all used 30w engine oil but I would like to confirm
Yesterday I was pushing snow in my D31-P and suddenly the right track quit driving. With the left track I can spin the machine forward or backward, but nothing on the right track. Is the right side steering clutch the most likely culprit? I'm afraid it's gonna have to wait until the snow goes away, but I'm still at the "staring at the ceiling" stage of grief and I'd like to know what I'm getting into. Thanks