Section for komatsu d20,21 and similar grey market dozers

[Don Shilling]

On a D21-a7 can anyone tell me what this device is or what is its purpose?

 

[Marcus Wyatt]

View attachment 208643

I like that. I'm going to do that with my d31. It would have to help with the heat if nothing else.

 

[g_man]

On a D21-a7 can anyone tell me what this device is or what is its purpose?View attachment 210507

They look like electric solenoid hydraulic valves. Just like a lever activated hydraulic valve but are controled by an electric switch rather than a lever. But they are either off or fully open. Can't be feathered like a manual lever valve. They could be used to switch a single control lever between between two different hydraulic circuits or cylinders. Like your blade angle lever could be switched between your blade angle and maybe the root/rock grubber depth on the back of the dozer depending on which position the switch is in.

gg

 

[Don Shilling]

They look like electric solenoid hydraulic valves. Just like a lever activated hydraulic valve but are controled by an electric switch rather than a lever. But they are either off or fully open. Can't be feathered like a manual lever valve. They could be used to switch a single control lever between between two different hydraulic circuits or cylinders. Like your blade angle lever could be switched between your blade angle and maybe the root/rock grubber depth on the back of the dozer depending on which position the switch is in.

gg

Well, they seem to be stuck right now so I'll leave them alone until I learn more about them! I have a push button switch on the blade control joy stick that activates the blade angle and bypasses the tilt.

 

[Legdoc]

Did Komatsu quit building the D21?

 

[Dozman]

They don’t make the D-21 anymore

 

[Karl Kreek]

Hello all, new to D21's, new to Komatsu & new to Dozers period. Been looking for something to clean some fence rows & build a trail/road around my farm in KY. Long story, but hoping to give as much info as I can to hopefully get my problem sorted out .

Brought home a D21P-5 that had been sitting for quite awhile a couple weeks ago. Knew it needed work going into it, but got it for a good price. Engine ran fine when loading it & the hydraulics worked well enough to maneuver it up on the trailer with the blade helping out despite having a dead (but not frozen, just no power to it) right track. I'm no mechanic, but I can turn a wrench so I tore it apart & found that the right clutch actuating piston had stuck open & froze in the engaged position leaving the right steering clutch to be free spinning. Clutch had rusted & seized in the open position as well. Ordered plenty of new parts from a nice gentleman named Darin in NY (thanks again sir!). I got everything put back together & went to fire her up & try out the new clutch.....& she wouldn't crank!?!? Seemed like the engine was hydraulically locked....but I couldn't figure why....we changed the oil, oil filter & fuel filter. Nothing especially wrong there, so I figured it was the batteries. I pulled them & had them tested, one bad, one good, so I bought a new batt & thought I was about to go home & fire up my new dozer....nope, engine still seemed like it was hydraulically locked, wouldn't spin more than a half crank.

So....I pulled everything to get the injectors out & see if I pumped fuel into the cylinders when bleeding the fuel pump after installing the new fuel filter. Sure enough, with the injectors out, the engine will crank over. Didn't seem to shoot fuel out, but shot quite a bit of oil out of the cylinders.....that cant be good, does that mean the cylinders or pistons are shot? Next problem, I try each injector individually to see which cylinder is having the issue. The engine wont crank & is hydraulically locked if either of, or both, of the middle two injectors are in. If the forward & rear injectors are in, but the middle two are out, she'll crank & crank no problem.

Anyone able to give me a clue as what to do next?

Also, I may have inadvertently dismantled an injector, looks like you have to have them adjusted right....well I didn't witness mark anything & I'm not sure how much spring tension to have on the adjustment screw underneath the top lock nut. I think I got it back in the ballpark.....can anyone tell me how to adjust that correctly?

Thanks to any & all for any words of wisdom or advice!

 

[g_man]

Hello all, new to D21's, new to Komatsu & new to Dozers period. Been looking for something to clean some fence rows & build a trail/road around my farm in KY. Long story, but hoping to give as much info as I can to hopefully get my problem sorted out .

Brought home a D21P-5 that had been sitting for quite awhile a couple weeks ago. Knew it needed work going into it, but got it for a good price. Engine ran fine when loading it & the hydraulics worked well enough to maneuver it up on the trailer with the blade helping out despite having a dead (but not frozen, just no power to it) right track. I'm no mechanic, but I can turn a wrench so I tore it apart & found that the right clutch actuating piston had stuck open & froze in the engaged position leaving the right steering clutch to be free spinning. Clutch had rusted & seized in the open position as well. Ordered plenty of new parts from a nice gentleman named Darin in NY (thanks again sir!). I got everything put back together & went to fire her up & try out the new clutch.....& she wouldn't crank!?!? Seemed like the engine was hydraulically locked....but I couldn't figure why....we changed the oil, oil filter & fuel filter. Nothing especially wrong there, so I figured it was the batteries. I pulled them & had them tested, one bad, one good, so I bought a new batt & thought I was about to go home & fire up my new dozer....nope, engine still seemed like it was hydraulically locked, wouldn't spin more than a half crank.

So....I pulled everything to get the injectors out & see if I pumped fuel into the cylinders when bleeding the fuel pump after installing the new fuel filter. Sure enough, with the injectors out, the engine will crank over. Didn't seem to shoot fuel out, but shot quite a bit of oil out of the cylinders.....that cant be good, does that mean the cylinders or pistons are shot? Next problem, I try each injector individually to see which cylinder is having the issue. The engine wont crank & is hydraulically locked if either of, or both, of the middle two injectors are in. If the forward & rear injectors are in, but the middle two are out, she'll crank & crank no problem.

Anyone able to give me a clue as what to do next?

Also, I may have inadvertently dismantled an injector, looks like you have to have them adjusted right....well I didn't witness mark anything & I'm not sure how much spring tension to have on the adjustment screw underneath the top lock nut. I think I got it back in the ballpark.....can anyone tell me how to adjust that correctly?

Thanks to any & all for any words of wisdom or advice!

Karl I would make this it's own separate thread and put it in the main Dozer forum. There are a lot of guys out there that know engines inside out.

Seems strange it would run good to load on the trailer and then lock up after an oil change. Almost like the top end took time to flood then oil ran down the valve guides. But don't go by me use the experts out there.

gg

 

[Don Shilling]

On a D21-a7 can anyone tell me what this device is or what is its purpose?View attachment 210507

I employed my powers of observation, deduction, optimized brain farts and discovered the function of these devices. They are activated by the bush button on the blade control lever and select between blade tilt and angle.

 

[Karl Kreek]

Karl I would make this it's own separate thread and put it in the main Dozer forum. There are a lot of guys out there that know engines inside out.

Seems strange it would run good to load on the trailer and then lock up after an oil change. Almost like the top end took time to flood then oil ran down the valve guides. But don't go by me use the experts out there.

gg

Thanks for the reply g_man, I got her running this morning finally. After I cleared out the cylinders with the injectors out I noticed that only the #3 cylinder was causing a lock with the injector in....well it was finally a decent weather day & the sun was out a bit. I got to thinking, we've had about 2 weeks of solid rainy days while I was fixing the clutch. I seem to think some moisture got in the valve cover & froze a couple of the exhaust valves? Well, I put everything back together & put some heat to the engine. Even took a propane torch to the exhaust manifold to make sure any ice would be melted in the head.

Well, after all the heat, engine cranked over quick as could be & she fired right up! Been pushing trees & clearing fences all afternoon

 

[dcara]

78 model d21-16 with crack in block letting water into oil. Ideas of sources for block preferably near Dallas Texas?

 

[dcara]

That s/b D31-s16 not D21

 

[Don Shilling]

78 model d21-16 with crack in block letting water into oil. Ideas of sources for block preferably near Dallas Texas?

Kent Baugh Construction in Hughes Springs, TX. 888-485-8698. They have a large Komatsu salvage yead.

 

[Krackerjack9]

trying to get my driverside front idler fork arm to slide back into the cyclinder, I took off the zerk grease fitting and I put a chain and ratchet to try to pull it back but know luck any thoughts on how to go about this??

 

[Krackerjack9]

here are some photos of the track adjuster I just don't know how to get it to go back im figuring from other photos of d20s im at the max end and I got some new tracks so I want to be able to adjust as needed but if im at the end then how due I im guessing get the old grease out or whats the best route if getting a new assembly is what is needed then I guess that's what I might have to due

 

[Krackerjack9]

the yoke came out no problem and its shinny no rust has a bit of grease/oil on it so im wondering if I just keep pumping grease in will the whole assembly come out looks like there is a snap ring but no sure how deep in it is, I don't want to mess with that coil looks like it would bite the heck out of you if it got released

 

[Dozman]

Just keep pumping the grease in and it will come apart. Then you can clean out the grease and push it back together after you open the fitting next to the grease zero. After the new track is on pump it back up to operating tention

 

[Krackerjack9]

well I talked to Ken and he told to loosen up that bolt that the zert fitting goes in well finally got it to move and some grease came out but not a lot maybe about 5in worth. so I got chain and binder and using the blades hydraulics pushing on the idler and nothing, I really don't want to keep pumping grease in it then im still at where im am now, found 2 whole units for 1300 each but really don't want to that rought ,, Ken said not to put any heat to it so im going to stick with that so that option is out.

 

[Krackerjack9]

Just keep pumping the grease in and it will come apart. Then you can clean out the grease and push it back together after you open the fitting next to the grease zero. After the new track is on pump it back up to operating tention

you sure this will work have you done this before??

 

[Dozman]

Does your machine have a 6 -way blade? If so put a block of wood between the blade and front roller and push back on it. If the grease zert is open it should push back? No heat because there’s seals inside there!