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Section for komatsu d20,21 and similar grey market dozers

Brianvanem

New Member
Joined
Apr 7, 2022
Messages
3
Location
South Carolina
Got the machine out to the property and finally got to put to work. Overall, it did great. I did have to come to grips with the fact that it isn't and never will be a D6, but after that, it was great to run and pretty happy with it. I did notice I was having to pull quite hard at times to get it to steer. I am going to work on that this coming weekend. Planning to double check all of the linkage lengths per the manual and adjust the brake bands. Does anyone know the socket size for the brake band adjusters off hand? The machine is 1.5hrs away and hate to get there without the one socket I need. Can't find that detail in the book. Thanks in advance. Dozer 1.jpg Dozer 2.jpg Dozer 3.jpg
 

Flash27

Member
Joined
Apr 24, 2022
Messages
5
Location
Cheyenne WY
12v or 24v?

My D21P-7 only has one 12v batt and the alternator puts out 17v but I see a lot of parts on line saying 24v and there is a lable in the engine compartment that reads 24v.
 

Welder Dave

Senior Member
Joined
Oct 11, 2014
Messages
12,257
Location
Canada
Would be good to find out for sure what voltage your machine is. 17 volts is a little high for a 12 volt system and too low for 24 volts. I'd guess 12 volts and maybe you need a new voltage regulator or the current one can be adjusted. You don't want to boil the battery. Is the 17 volts the same when measured at the battery as when measured off the alternator? An auto electric shop or maybe someone on here can tell you what volts your alternator is by the numbers on it.
 

Flash27

Member
Joined
Apr 24, 2022
Messages
5
Location
Cheyenne WY
Is the 17 volts the same when measured at the battery as when measured off the alternator?
17v from alt only. batt measures 12+v until i start the motor then it slowly runs up to 17+v.
Also been having starting problems. Only starts first thing in the morning, then i have to jump the silenoid terminals for the rest of the day.
i read on here about the starter safety relay detecting/thinking the motor is running when its not if the diode in the alt is bad. That combined with 17v probably means a new alt should fix both
 

Flash27

Member
Joined
Apr 24, 2022
Messages
5
Location
Cheyenne WY
i see engine numbers listed when shopping for parts but not my exact number yet.
Any here know if my number 4D95S-1 is 12v or 24v or any other info from the #?
 

Welder Dave

Senior Member
Joined
Oct 11, 2014
Messages
12,257
Location
Canada
I would for sure have your alternator and voltage regulator checked out. The shop could tell you for sure if it's 12 volt which I highly suspect it is.
 

Flash27

Member
Joined
Apr 24, 2022
Messages
5
Location
Cheyenne WY
I just got it at an action and it only had one 12v batt. Other than that, all signs are pointing to24v. Makes more sense too, insted of an old 12v alt going rouge and start putting out17v... an old 24v alt dropping to 17.
Thanks for the info.
Where can i get parts/inf t fix a sticking/leaking hydraulic control valve?
 

Welder Dave

Senior Member
Joined
Oct 11, 2014
Messages
12,257
Location
Canada
An auto electric shop can tell you what it is by the alternator and/or the starter. It is pointless to be guessing.
 

akajun

Member
Joined
Jun 22, 2021
Messages
6
Location
brusly, LA
tearing into my steering clutch on my d21p6, left side has about 1" of light oil in the case. Going to rebuild the steering booster cylinder but was also goin to replace the oil seal on the bevel gear since Im there already, and IDK if its leaking from the steering cylinder or the bevel gear case or both. Anyway I know I have to pull the inboard flange but can I pull the seal from the steering case or do I need to pull bevel gear shaft as well?
Ive seen were the -5 and below is changed from inside the case on both the bevel gear and the final drive but on the -6 the final drive is done from inside the final drive but Ive seen conflicting reports on the bevel gear oil seal on the -6. Anyone have any firsthand experience or knowledge?
 

darinray

Charter Member
Joined
Nov 15, 2003
Messages
435
Location
Delevan, NY
Occupation
Owner-Equipment & Parts Sales
Yeah you can just pull the inner flange out using the 2 bolt holes built into the center acting as a puller... Then just change the seal out that way... You don't need to remove the shaft... Keep me in mind for all your parts needs if you still need them... May not be the cheapest but I try to help with service questions too... :)
 

akajun

Member
Joined
Jun 22, 2021
Messages
6
Location
brusly, LA
Thanks, Ill prob be calling soon. As far as price, Im dealing with H&E equipment in Baton Rouge who is the Komastsu dealer here so im sure youll be cheaper by a long shot.
Another question, Im looking at my service manual, It looks like the final drive seal is pulled from inside the steering case as well on the 6 series. Is that correct?
Yeah you can just pull the inner flange out using the 2 bolt holes built into the center acting as a puller... Then just change the seal out that way... You don't need to remove the shaft... Keep me in mind for all your parts needs if you still need them... May not be the cheapest but I try to help with service questions too... :)
 

darinray

Charter Member
Joined
Nov 15, 2003
Messages
435
Location
Delevan, NY
Occupation
Owner-Equipment & Parts Sales
Oh for sure I'll be cheaper. :) LOL... Yes same as the bevel gear side flange they pull off same way and seals replaced from the inside cavity... Good luck and talk soon...
 

oldhousehugger

Well-Known Member
Joined
Apr 15, 2007
Messages
122
Location
Dallas
akajun; Here is a pdf of the page out of my Komatsu manual for D21D. I'm seeing that if you pull out the steering clutch drum and remove the Bevel gear shaft hub the seal could be pried out and a new one installed without any further digging.
 

Attachments

  • D21 steering clutch 001.jpg
    2.1 MB · Views: 11

oldhousehugger

Well-Known Member
Joined
Apr 15, 2007
Messages
122
Location
Dallas
Got the machine out to the property and finally got to put to work. Overall, it did great. I did have to come to grips with the fact that it isn't and never will be a D6, but after that, it was great to run and pretty happy with it. I did notice I was having to pull quite hard at times to get it to steer. I am going to work on that this coming weekend. Planning to double check all of the linkage lengths per the manual and adjust the brake bands. Does anyone know the socket size for the brake band adjusters off hand? The machine is 1.5hrs away and hate to get there without the one socket I need. Can't find that detail in the book. Thanks in advance. View attachment 258238 View attachment 258239 View attachment 258240


Just a thought about having to pull hard to get the D20 to turn. If tightening up your brakes doesn't do the trick it may be something else. Make sure your parking brake is completely disengaged! Check your hydraulic assist clutch system pressure. Without sufficient pressure from your assist cylinders your steering clutches will not disengage. There are ports on top of the steering valve box in front of your batteries. Page 21-65 in my manual. I believe the system pressure needs to be above 200 psi to work right. If the filter in front of the hydraulic pump in the bottom of the clutch housing gets clogged up it will starve the pump for oil giving low pressure. That pump also lubricates your wet clutch so it is important to check.
You need to drop the rear belly pan and drain the oil from the wet clutch housing to get to the pump.
How do I know about this? Mistake after mistake. I didn't realize my machine had gotten flooded and water got into my wet clutch system and I ran it like that. That ate the cork off the clutch plates which got caught in the filter down there and starved the pump. There I was couldn't steer or move at all. I wrote about this on Dec. 20 2016.
 

oldhousehugger

Well-Known Member
Joined
Apr 15, 2007
Messages
122
Location
Dallas
Writing about clutches made me think about all the work we have done with our little machine. The first picture is the dozer in the bottom of a brand new tank we had dug back in 2007. I was smoothing out the globs of clay the D9 left after he finished roughing out the hole.

The next picture is the same tank 2 weeks ago (late July 2022). It had almost completely silted in having been subjected to several big floods over the years since it was first dug. The next picture is my D20 working in the same hole cleaning the edges of where the huge Case excavator is scooping out thousands of yards of black slimy ooze. We almost got all the way to the original bottom like in the first picture but the slop was starting to run back in the hole. My right track steering clutch pack was going out so I had to let the excavator clean up as best he could without me.

The excavator did the work albeit with my small input in about 10 hours. Lucky for him he had AC in the cab. Obviously I do not. It only got to 99 Saturday Aug 6 2022 in Gholson Texas. It was a good bit cooler than the previous week. stock tank dozer and trailer 036.jpg dry tank.jpg 20220806_110326.jpg 20220806_152344.jpg
 

Spkerking

New Member
Joined
Jul 12, 2022
Messages
2
Location
washington state
I have a new to me what I think is a D20P -5 I posted some pictures. I need to replace the clutches and the final drive was removed. I was told the backhoe was a factory installed. would love to fine the manual for the machine and the backhoe. any info would be great! runs well and hydraulics function well with no leaks.20220807_132005.jpg 20220807_132005.jpg 20220807_131150.jpg 20220807_131212.jpg 20220807_131228.jpg
 
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