Section for komatsu d20,21 and similar grey market dozers

[mitch504]

Sorry to hijack. I've been looking over this thread for quite some time trying to resolve the issues on my little dozer. I have a -6 model and could desperately use that wiring diagram! It was rigged up with a two wire starting system (as in touch two wires together to start) when I got it. The alternator was bypassed as well for some reason. I plan to do a write up of all the stuff I've been doing to the dozer here soon.

Mitch if you could email me that wiring diagram that would be awesome!
wagnon89@gmail.com

Thanks,
Justin

email sent, let me know if you can't read it
Good luck

 

[RRRancher]

Hayes, there is a guy who posts on here at times. His name is darinray, if I remember correctly, and he sells parts for steering clutches, and maybe completely rebuilt units also. I'm not sure. You would have to ask him. Look back a few pages for some of his posts and you can find his contact info. I think he has the best prices around from what I've heard.

Edit: Here, I found his website link. http://www.dmmsales.com

Bezarker and wagon89, in case you need more than just the electrical schematic, if you look back a few pages I posted a link to a place online where you can order and download the entire shop manual for these dozers in PDF format for a small fee. They are as good a quality as you can get. The original shop manual has crappy pictures itself, so the PDF format is not the problem. In the electrical section of the manual, at least for the model I have, the D20A-6, there is only one page and it is the schematic.

 

[wagnon89]

Thanks Mitch! That will help a ton.

 

[wagnon89]

Bezarker and wagon89, in case you need more than just the electrical schematic, if you look back a few pages I posted a link to a place online where you can order and download the entire shop manual for these dozers in PDF format for a small fee. They are as good a quality as you can get. The original shop manual has crappy pictures itself, so the PDF format is not the problem. In the electrical section of the manual, at least for the model I have, the D20A-6, there is only one page and it is the schematic.

RRRancher, I have a manual that I downloaded for about ten bucks but it is for a d20/21a -5. I figured it would be close enough but there is no electrical section in there at all. And there's a few things that look different than what my Dozer looks like. May have to go back and find that link and order the correct manual. Thanks!

 

[Bezarker]

Thank you Mitch, I had to ask him for the owners manual which he brought in this morning. It's a D21P-6 and it's been sitting for about 3 and 1/2 years now. He's an older dude and a bunch of us around the office really want to help him. Whatever you can do sure will be appreciated.

 

[Bezarker]

I tired ordering the service manual and I keep getting this message: Looks like a double submit or you have reloaded the page on error. Please go back and start over... I'm gonna try it again later on, just hope I haven't purchased 4 downloads...

never mind it seems I forgot how to use the interwebs. I got the manual and we're planning on going down to his property in the very near future. Thanks for the link RRRancher.

 

[RRRancher]

Glad I could help, Bezarker. I just wish the electrical section had a bit more substance to it than just a schematic. It took me a while to decipher some of it and I worked on electronics for almost 30 years. If you have any difficulty with it, I might be able to help you somewhat. It is, indeed, a very simple electrical system. The Japanese have a knack for removing anything excessive and simplifying things to extremes. I worked on CAT scanners for General Electric in the 70's, 80's and 90's, and later in that period of time we bought a Japanese company that also made CAT scanners. When I went to school on them, I was amazed at how they did the same things we did on the GE-engineered scanners with a lot less of everything. We sold them as a cheaper model then the ones we made in the states, and they worked as well as ours, in my opinion. It was a real eye-opener for me. I guess that is why I love these little dozers so much. Simplicity that does the job.

 

[RRRancher]

Just saw this on Craig's List for this area in case any of you need parts.

http://easttexas.craigslist.org/hvo/4528274630.html

 

[Beach Bubba]

I need a blow up of parts for the fuel pump on my D20-a. I may have lost something the last time I had it apart. I can run for a while then it looses power and dies with black smoke....sometimes wait a few days and it starts and runs fine for awhile then under load it starts missing and looses power..then dies.

 

[RCMEDIA]

Hey guys I am new to the forum and joined because I am thinking of getting a Volvo L20 loader I jumped in because I have owned a D 21 for some 15 years now and never had any problems at all. Mine is hydro shift, its real sweet no clutch needed jus slide her in gear. I store mine in a steel building and it runs as good as the day I bought her. Since Im looking at a new loader I might consider selling her if there is any interested parties email me or call and Ill shoot some pictures. If anyone has questions I would be happy to answer them the D21 is a perfect size machine not too small and not too big it can be hauled with a pickup truck.

Mike 540-721-3124

 

[Beach Bubba]

D20A-6 Lift Cylinders

...Has anyone information or video for rebuilding the lift cylinders. I have heard, but can't find the source, that it is difficult to remove the pistons...Mine is leaking bad and needs to be repaired...I live in a busy oil field area (Eagleford Shale) and the repair shops do not want any business from casual users...and the prices are incomprehensible. I was quoted over $400 and 3 month wait. Obviously they don't want my business. Thanks for help

 

[Beach Bubba]

...got'r fixed...was the screen in the banjo bolt....after coughing and spitting for a couple minutes, she caught on and ran smooth...throttle up or down....first time in a long while...I never saw that filter and it isn't shown in the parts blow up when I rebuilt the lift pump awhile back.

 

[hanlon]

Hi new to this
Just fitted some rippers my son made to my D20 see photos

 

[g_man]

Hey !! - They look pretty good. Your boy does nice work.
What is your plan for the hydraulics ? A diverter valve on one of your blade circuits or a new ciruit with it's own valve ?

 

[hanlon]

Hi g-man
Hydraulics all done diverter valve and some pipes and adaptors
Ripper goes up and down ok but I haven't ripped anything yet . Have photos of hydraulics

 

[John25mm]

That looks great. I would love to see pictures of everything and if you have drawings even if they are on a kitchen napkin they would be great. This is just what I have beeen wanting to do to my D20.

 

[hanlon]

What we did to start off was take a template of the holes in the back of the dozer on some thin plastic sheet stuck on with some double sided tape and cut the holes out, then stuck on to a piece of plywood board and drilled the holes out on the board and then set it off the ground at the right height of the dozer.
The ripper tines are off a grader. I can measure it all up for you.

 

[John25mm]

Thanks for the info. Some further questions for you. Was there anything behind the holes that either leaked or the bolts in the holes held in place? On mine they are just flat with the back plate like plugs. Do you remember the bolt sizes? What size hydraulic cylinder do you have on there? I ask these questions because mine is 600 mile from me and if I am going to do any of this I need to prep as much as possible before heading to Ohio. Thanks for what you have shown already. This looks great.

 

[hanlon]

My model is a D20A-6 other models my be different, the bolt size is metric 16 mm I used high tensile 8.8 bolts plated with thread all the way up 2 inches long
I believe the -7 has 18mm holes as you can buy a three point linkage being Komatsu I think it would be expensive.The back of the Dozer I think is about 1 inch thick and the holes go right thru.
You have to brush any dirt out of the threads before installing bolts and some tighten on the way in but didn't seem to damage the thread on the bolts may be a locking devise ,I put grease on the bolts before installing.I left the tow hook in place and you may get oil from bolt holes down the bottom if seals are leaking on drive sides and the oil level is dropping in bevel gear area (diff ) I think this right I have never had mine apart.The plate up the top with about 6 bolts in it is sealed and opens up the bevel gear oil area, I will tell you later about what I did with this plate . The Hyd Ram Bore 2 1/2 inches - stroke 12 inches -closed length 20 inches -shaft dia 1 1/2inches - Ends 3/4 inch which we drilled out I think 7/8 inch View attachment 121652View attachment 121653
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[John25mm]

Thanks. That answers a few question because I also have not had to open up the rear end of mine. What brand of diverter valve did you use? If you could do it over again is there anything you would do different? Mine is a D20A5 so it should be similar but given my luck it will be that one they desided to experiment with. You and your son did some great work and I hope to do half as well. In looking at it I am thinking about how I can add linkages to it so I can pull some of my 3 point hitch attachements. Again thanks for the info and hope to talk to you some more. Welcome to the site.