Komatsu D68E-1 Brakes needing repair.

[ferrret3238]

Hello, My neighbor bought a D68E-1 dozer just recently. The brakes do not work on it and he's wanting them fixed before he puts it to use. Sometimes he's on sidehill's so brakes would be beneficial there. I have never torn into one of these and was wondering where to start and what to look for? Some manuals came with the machine but I have not looked at them yet. Looks like a decent machine and has a 855 cummins in it. Has about 13000 hours though but still seems like a good running machine from what little I know. Is there anything else I should be looking at with this high of hours too?

 

[John C.]

Brakes are under the cab. The pedal linkages run from under the dash panel all the way back to levers or valves under the operator seat. The internal parts are just about like a Caterpillar system with clutch drums surrounded with band type brakes. There will be adjusters under plates accessible from the back of the machine under the fuel tank. Make sure the linkages are free to move and try to adjust them first. In order to get to the internal parts you have to remove the operator station and usually the fuel tank. I don't envy that job for anyone. Make sure the neighbor can afford to pay you for the aggravation.

 

[Dave Neubert]

Iam doing one now I had the steering clutches sitting on the floor in 8 hrs

 

[John C.]

Are you working on a cab machine or just OROPS?

 

[Dave Neubert]

ROPS

 

[John C.]

That's pretty good. Have you done them before?

 

[Dave Neubert]

D65 D63 pretty much the same thing

 

[Dave Neubert]

Have you tried adjusting them in the back under the fuel tank there is a 2 bolt cover at the rear of the brake housing. Take it off and turn the hex head in to tighten them don;t adjust linkage to the pedals

 

[ferrret3238]

Forgot all about this thread. I am tearing into the machine now. He used it for about 100 hours on a pond job and one of the tracks won't steer now. I checked the pressures at the 4 ports on the back of the machine and got close to 285 psi on all of the 4. The brakes didn't really work before even after I tightened up the adjusters under the caps. I'm thinking the brakes are so shot that when he tries to turn the machine tries to brake the drum and it cannot stop it so it just coasts with the steering clutches disengaged and keeps rolling forward on the left side. Have the parts manual and the shop manual that goes into decent detail on how to tear it apart so I'm doing ok so far. Its been take some stuff off then power wash then take some more stuff off and power wash again. The book is a little fuzzy on how to take the clutch drum out of the machine. It says to rotate it and take the bolts out of the drum but I was wondering if there's a center shaft that goes through the clutch plates that it will slide off of? Also would it be easier to remove the whole plate or just the brake tower covers?

 

[Dave Neubert]

The clutches are on flanges you have to roll machine forward to get to all the bolts just rolling it a little bit rotates the clutches a lot I use a jack on the cleats to roll it make sure to reseal your clutch pistons wile in there

 

[ferrret3238]

I got the thing apart and replaced the band brake pads. The ones in it were worn down to about .125 or less. Some of the brass rivets fell out also being the pads were so thin. Ordered some new pads from a company called Blumaq and the pads look pretty good. Had to countersink the holes on the new pads just a little more for the rivets though. New pads were about .375 thick. Riveted on the new pads, kind of a chore putting in all 128 brass rivets but I made a small c frame press tool to do it on the table and worked really good. Forgot to look at the clutch pistons, Hopefully Its good though being I was getting good pressure on the test ports. Measured the steering clutches and spacers and they were all in spec too, and looked good so I didn't have to do anything with them too. Only issue i have so far is that the book says to adjust the brakes the front bolt has to just touch the front piston which is done and then torque the rear adjuster to about 65 ft lbs. Then as the book says tighten the adjuster counter clockwise 1-5/6 turns. This is confusing, counter clockwise is looseining the adjuster as I look at it. I didn't think I could go another 1-5/6 turn in after tightening it to 65 ft lbs so I loosened it. I guess if it slips or drags ill just adjust it accordingly. I would assume one would want the brakes to slip right now with the machine sitting, not in gear, so it won't take off until revved up.

 

[John C.]

I think you have it correct. You don't want the brakes dragging when the machine is traveling in forward or reverse. Once you get the machine running again, you adjust the brakes to your preference.