Section for komatsu d20,21 and similar grey market dozers

[CavinJim]

It doesn't really matter too much which way the fan is blowing--it shouldn't be getting that hot either way. I've had three track loaders and they all have had reversible fans. If you're working a fire you want the fan blowing out (forward) so you don't suck hot air or flames into the rad/engine bay. Winter you want them blowing in--really helps keep the operator warm! Sounds like you might have some other issues.

 

[Krackerjack9]

hmmmm wonder what I need to check first?? thermos stat then I guess water pump, engine runs smooth as can be and starts up on the very turn of the key

 

[Krackerjack9]

pulled the upper hose and no thermostat, put it all back together started it up and opened radiator cap to see what was going on, well looks like there is pretty good movement of coolant but I don't see any bubbles that would eliminate a head gasket issue, and with that the motor is pretty darn clean and I'm sure it was washed pretty good. But I have ran it for a good 15hrs and I don't see any type of seepage around heads and oil is just a tint of color on it but its not like super black. So this leads me back to the fan, now the oil cooler on the front shapped like a W from what I read its engine oil cooler so with the fan blowing thur the radiator seem like the oil cooler would not get cooled per sea and it would just keep getting warmer or hotter as time went on??

Thinking about reversing fan and then in front of radiator put a electric fan between the shield and radiator looks like there is plenty of room for one.

Or due I need to chase this overheating issue some more, not sure what else to check for except pull radiator and have it gone thur?? thoughts??

 

[T Curtiss]

I would install a new thermostat and cap and really look at that radiator, just to make sure its not stopped up or gunked up somewhere. I rented a 450 cat and the fan drew air across the motor and blew out the front of the machine to keep from sucking in all that dirt and caking up the engine compartment,,, I do know that some backhoes and ditchers we used at a company I used to work at,,, if they didn't have a stat and good radiator cap,, they would overheat in just a bit. Hope this helps,,, maybe someone else will chime in that knows better than I!

 

[Krackerjack9]

according to parts books the fan is supposed to blow away from the engine, I can see how they would want it this way, going to order a electric fan any way and mount it on the front on the bottom and see how that works for now,

 

[DMiller]

Have to agree on the lack of thermostat issue, saw this years ago both on heavy engines and gasoline engines where someone thought they could get more cooling without one. Problem is coolant flow does increase TOO MUCH, blows thru the radiator without enough time in the core to actually cool it down. We went to installing gutted thermostats on racing gas engines just for a restriction and re-installed t-stats in the heavy engines to do as were designed.

 

[Krackerjack9]

well I'm going to take the advice and put it all back the way it was add a thermostat and going to add a electric fan in the front just for piece of mind incase it starts climbing then I can turn it on and see what effect it has.

 

[Krackerjack9]

Started taking everything off and just to go thur it, no real surprises except when I took the hood off, well surprise!!! From the muffler to the one on the hood there was no pipe extension. So I'm thinking that would have added to the over heating issue, the fan starts pulling in heated exhaust and pushing that thur the muffler I'm thinking that might have been enough to cause the problem.. Which leads to my other problem.. I bought a 12volt fan but I for got the Komatsu is a 24volt system. I don't think there is a way I can wire it to the battery hooked up in a series.

 

[RRRancher]

If you attach a wire to either end of the jumper that connects the two batteries together, you will have +12 volts on that wire in reference to ground. You will need a switch between that wire and the fan, so you can turn it on and off. An inline fuse would also make it safe as well. Ground the other fan lead and you should be good to go. It would be much easier, of course, if the fan was a 24 volt model, as you could connect it to the ignition switch where it would come on when you turn the key on.

 

[T Curtiss]

Finally got it and can call it mine! Will haul it to my land this weekend and have a little fun!

 

[RRRancher]

Congrats, T Curtiss. I hope you enjoy it as much as I enjoy mine. They are tough little machines and fun to use. They do occasionally have issues, but what can you expect from a machine this old? The good thing is that this forum has covered many of the problems they have, some in detail. I have not had much help searching for something, but it doesn't take too long to browse through all 113 pages. There is a lot of goo info here.

I see you're in the Cleveland area. I was born there many moons ago, but raised elsewhere. Most of my relatives are in the vicinity. It's very similar up here in the Henderson area. Piney woods with iron ore colored dirt. And it gets on everything.

 

[T Curtiss]

I was raised in Ft. Worth area and after selling everything up there, My sister had moved to Cleveland for a job, and on visits,,, I just fell in love with the little town. I bought 6ac out in the Sam Houston National forest and just love it out there. I bought this old machine from a buddy of mine and really excited to tinkering and rebuilding it.... and this site,,, and the post,,, just awesome!!!! and a Big Thank you to you and all the other posters for the invaluable information and tricks that I have learned reading these post!!
I'm working down here in Freeport on a project that should last a couple of years, maybe we can meet and have a Dr.Pepper some evening on my way thru!

 

[tpitt]

Has anyone built a decelerator for a Komatsu D21-a dozer? I would like to put one on my 1995.

 

[T Curtiss]

Ok,,, for anyone that still looks at this page,,, I have my D20-6 up and running great! It will push a full blade and then some,,, really happy with the machine! But before I tear in and replace the clutches,,, it will drive first off like a champ,,, gradually turning in both directions,,, then after maybe 10 min of use,,, I have to pull the handles out until the street brake locks to get it to turn at all,,, then the brakes will not work for a bit,,, then it goes back to working fine,,,, like it has a hydrolic stoppage going to the actuators for the clutch disengagement,,,, the it stops working the brakes too,,, I think I remember that there is some screens I need to clean,,, but dang if I remember where I read them,,, just like they need bleeding,,, but I know that’s not right.

One other deal that y’all might have a answer to,,, the clutch pedal,,, way too high,,, have to really hike my leg up to get on it!!! Everything works well on this machine and I have no plans on selling it,,, just neat to have one around the place,,, and don’t mind turning a few wrenches! I’m sure it just needs a little TLC!

Merry Christmas to all! Tommy

Found a great post on page 106 about the strainer in the wet couch that may solve my streering problem,,, will clean it and get back with more info soon,,,, but the clutch pedal has me stumped

 

[T Curtiss]

Well the trans screen cleaning didn’t work. While adjusting the brakes I could see signs of oil on the right clutch with the little covers off. I did get the clutch pedal adjusted with the correct free play and at the right height,,,
So now it’s time to talk to someone about parts and what else needs to be fixed while in there! I’ll post pictures while I’m doing the repair if anyone it interested,,, but it might be a bit,, have to wait for parts and another long weekend to work on it!

 

[dayin henry]

Welcome rangerfreak

Welcome aboard rangerfreak:drinkup , I'm not a Komatsu expert but there are a few guys here that do qualify. So fire away and someone will probly answer all your questions.

i got a d20a-5 and am having trouble with the steering clutchbrake i am having trouble removing it and locating replacment parts

 

[T Curtiss]

i got a d20a-5 and am having trouble with the steering clutchbrake i am having trouble removing it and locating replacment parts

Call either one of these guys:
www.dmmsales.com Darin Ray in NY
www.kentbaughequipment.com in Texas
I just ordered a full set of clutches and brake bands from Kent this morning,,, both these guys have numerous post on this thread and can get all the parts you need with reasonable pricing,,,, both also sell on eBay
Good luck and let us know how things turn out
Tommy

 

[dayin henry]

Call either one of these guys:
www.dmmsales.com Darin Ray in NY
www.kentbaughequipment.com in Texas
I just ordered a full set of clutches and brake bands from Kent this morning,,, both these guys have numerous post on this thread and can get all the parts you need with reasonable pricing,,,, both also sell on eBay
Good luck and let us know how things turn out
Tommy

i got both clutches out but dont know how to get the clutch bar and the iner plate to remove the thro out bearing i thing its what they call and ideas

 

[Minnesota Eric]

How much of a PITA is it to turn the pins on the chains on a D21?

 

[excadoz]

I'm having issue with my D21, it's main clutch won't disengage, that every time I switched it on, the dozer will just move forward right away.

Currently, the dozer is not touching any ground, to prevent unwanted accidents.