Section for komatsu d20,21 and similar grey market dozers

[mcbike57]

Welcome to the forum.. Yeah there is a pile of pages in this section and I can remember when it was started. Well barely but still.. WOW times flying.. If the steering clutches are not releasing when trying to turn it will bog the engine down IF the brake bands are functioning properly too. If they are slipping for some reason then the tracks will stall out (not turn) when pulling a lever or putting machine under a load.. Will need more details on what its doing..

Checked brake adjustments. steering linkage adjustments and inching clutch adjustments today. All are within spec (very close to anyway, enough to do the job/give some results) Actually adjusted the brake band adjuster back 2 turns from the suggested 4 turns out. Fired little dozer up and it wanted to creep. (D21A-6). Both steering rods pulled fully back will stop unit. Brake action by brake pedal is zilch. Steering rod action is almost none. Will respond slightly to one or the other, but very slightly. I feel the brake shoes are worn out and most likely the steering clutches are too. It will move back and forth, but I still have yet to put it under a load. Suggestions?

 

[darinray]

If your pulling the lever all the way back toward your chest the brakes need to be tightened so the lever travel is only like 6-8 inches or so (not sure on exact) but when adjusting the brakes tighter you should feel the resistance in the levers when pulling actuating the brakes inside. You can see the linkages first start to release the steering clutches by pushing the steering valve spool in the body and then the brake arm moving engaging the brakes.. Is your engine bogging down when trying to steer? I suspect not so you will need to tighten brake lining clearance.

 

[mcbike57]

If your pulling the lever all the way back toward your chest the brakes need to be tightened so the lever travel is only like 6-8 inches or so (not sure on exact) but when adjusting the brakes tighter you should feel the resistance in the levers when pulling actuating the brakes inside. You can see the linkages first start to release the steering clutches by pushing the steering valve spool in the body and then the brake arm moving engaging the brakes.. Is your engine bogging down when trying to steer? I suspect not so you will need to tighten brake lining clearance.

Will try that. All other linkage adjustments are close to spec. Pretty sure that you or Mr. Baugh are going to get a few bucks out of my wallet soon. By the way there is no engine bog what so ever! Maybe that is a good indicator of worn out clutches! Little feller just wants to go forward or backwards and the sweet spot for neutral is hard to find. Gear cable may be a little stretched? Might need one of those also!

 

[darinray]

Ok.. Contact me anytime.. Keep in mind that these steering clutches are always engaged so that is why it's goes back and forth right now. If you put it under load and the tracks don't stall they are gripping good. (push the brake pedal on the right in to see if engine strain) But first I think you have to tighten the brake adjusting nut on it to get a result here. If when you hvae your brakes adjusted and when pulling a lever they don't stop a track but lug the engine down then you have a problem with them not releasing. Talk again soon.

 

[GuglioLS]

mcbike57 - soooo......... if you pull back both steering levers at the same time, does it keep going? without bogging? If so two problems 1.- neither steering break is engaging or gripping and 2. - neither steering clutch is disengaging. If you put it under a load, like drop the blade or up against a large tree, then pull back both steering levers at the same time and it still does not disengage got to check to be absolutely certain the steering clutch hydraulic spools are being pushed in when pulling back on the levers. Check steering clutch hydraulic pressure, there are two ~ 1/8" npt plugs on the underside of the steering clutch spool valve body where pressure can be measured, it should be ~ 215 PSI when spools are depressed, if that checks out then...... I would have to say both steering clutch packs may be rusted together and not releasing or (rare) clutch yolk bearings (similar to throw out bearing) are completely disintegrated (one of my clutch yolk bearings let loose last summer) I replaced both which was quite a project, had to make a special tool. From what you describe it sure sounds like neither break band is adjusted or somehow not engaging. Even if the clutches are not disengaging the breaks should as it is a direct mechanical connection through linkage to the break bands. Good luck with it.... Take the seat and seat plate out, then the floor plate so you can get a real good look in there to see what is going on.

 

[mcbike57]

mcbike57 - soooo......... if you pull back both steering levers at the same time, does it keep going? without bogging? If so two problems 1.- neither steering break is engaging or gripping and 2. - neither steering clutch is disengaging. If you put it under a load, like drop the blade or up against a large tree, then pull back both steering levers at the same time and it still does not disengage got to check to be absolutely certain the steering clutch hydraulic spools are being pushed in when pulling back on the levers. Check steering clutch hydraulic pressure, there are two ~ 1/8" npt plugs on the underside of the steering clutch spool valve body where pressure can be measured, it should be ~ 215 PSI when spools are depressed, if that checks out then...... I would have to say both steering clutch packs may be rusted together and not releasing or (rare) clutch yolk bearings (similar to throw out bearing) are completely disintegrated (one of my clutch yolk bearings let loose last summer) I replaced both which was quite a project, had to make a special tool. From what you describe it sure sounds like neither break band is adjusted or somehow not engaging. Even if the clutches are not disengaging the breaks should as it is a direct mechanical connection through linkage to the break bands. Good luck with it.... Take the seat and seat plate out, then the floor plate so you can get a real good look in there to see what is going on.

When both steering levers are pulled completely back the machine will stop. No bog, no pull, it will stop. See where you are going with this. Will dig in and check it out. Thank You for the insight and reply!

 

[GuglioLS]

mcbike57,

That is good news, both steering clutches are dis engaging . That leaves the issue to be neither steering break is catching. Got to tighten up those nuts under the caps in the back. I think you might have mentioned earlier that you tired tightening those nuts? (could be the threads are badly rusted?). Try again, this time (with the engine off) have someone pulling back all the way on the left lever, then start tightening (CW) the left nut until the lever starts going forward, then go about 1 more turn. Do the same on the right. The goal is to make sure the clutches disengage first, then the breaks start catching so as to stop one track at a time so it turns (steers) one way of the other.

A word of caution - do not, and I really mean do not unscrew those break thension nuts out (CCW) off the threaded shaft or you will be taking apart the entire back end and removing the steering clutch case cover to fish the shaft back through the break actuator mechanism a real PITA. Been there done that 4 times. Once to replace both steering clutches and break bands, then a couple years later to replace the steering clutch release yolk bearings.

 

[GuglioLS]

Been kind of dead around here so here goes......
Hard to believe 12 years have passed since acquiring my hobby Dozer. This forum seems to be a good place to document and archive the maintenance history of my D20A-6. Perhaps also an inspiration to look for maintenance opportunities of your own. With all that said here goes with an update on the “Little Dozer that could”:

The Winter of 18-19 set in and not much to do outside with the dozer so I decided to do some preventive maintenance and restoration of the entire cooling system, then the exhaust. But before all that I pulled the steering clutches out (for the second time) only this time to replace the steering clutch yolk bearings. Sorry no pics of that project, that's why she is still up on blocks. Back to the cooling system..... First was to drain the radiator, loosen hose clamps and a wire for the head lamps. After that I rigged up a winch on my scissor lift to remove the entire front cowling with radiator attached. The front cowling (that's what I call it) is held on by eight bolts, four on each side. It is amazingly simple to remove the entire assembly with radiator attached, just need a means of lifting it up and out of the way.

First couple of pics show the front cowling assembly removed the radiator is attached to the cowling.

 

[GuglioLS]

After removing the radiator from the cowling, the cowling was cleaned up, sanded, primed with Red Rust-Oleum, then Gray Primer then the finish coat. While the Alkyd Enamel was trying to cure, the radiator was taken to a local radiator shop to be rod-ed out, flushed, pressure tested then painted.

 

[GuglioLS]

While the Radiator was at the rad shop in Albuquerque, NM, the water pump was removed and replaced with a brand new one from Amazon. Amazing to get a brand new water pump off Amazon for a very reasonable price. The old one will get rebuilt sometime this summer for a spare or re-sale. A new 82*c thermostat was installed at the same time.

 

[GuglioLS]

Radiator took a week - those guys took their sweet old time but did a great job, its as good as new. Got it reattached to the cowling, hooked up to the scissors lift then "drove" it over to the Dozer, lowered it down, then bolted it all up just like that (all by myself).

 

[GuglioLS]

Now its time to install and re-connect the hydraulic fluid heat ex-changer and hoses...... after that clean up the hood and paint the underside of that rust bucket. Its too darn cold to paint any more. It has been in the singe digits early in the mornings and teens in the afternoons. I will give the entire dozer a paint job when it warms up this spring, summer or fall, you get the idea - basically with I get to it. In the last pic you can tell my supervisor is well pleased with the results while at the same time keeping my ride back to the house warm and cozy.

 

[GuglioLS]

Its time to go to turn-in for the evening, will post next on the new Smoke stack a.k.a muffler tomorrow night. here is a teaser....

 

[mcbike57]

mcbike57,

That is good news, both steering clutches are dis engaging . That leaves the issue to be neither steering break is catching. Got to tighten up those nuts under the caps in the back. I think you might have mentioned earlier that you tired tightening those nuts? (could be the threads are badly rusted?). Try again, this time (with the engine off) have someone pulling back all the way on the left lever, then start tightening (CW) the left nut until the lever starts going forward, then go about 1 more turn. Do the same on the right. The goal is to make sure the clutches disengage first, then the breaks start catching so as to stop one track at a time so it turns (steers) one way of the other.

A word of caution - do not, and I really mean do not unscrew those break thension nuts out (CCW) off the threaded shaft or you will be taking apart the entire back end and removing the steering clutch case cover to fish the shaft back through the break actuator mechanism a real PITA. Been there done that 4 times. Once to replace both steering clutches and break bands, then a couple years later to replace the steering clutch release yolk bearings.

GuglioLS,
First, Thank You for the helpful info. Really appreciate it. Now here is what has happened since then. Bought new brake bands and a full set of steering clutches. Popped the tops and found that the last person in had either not hooked the rear finger up to the brake bands or someone had done just what you warned against. Pulled brake/steering drums. Right side was very rusty and showed significant wear. Left side was a lot better in appearance, but also showed significant wear. Cleaned up and installed new bands and clutches. Blade lift spool packing was really spewing fluid out the top. Installed new packing, but made the mistake of pulling the control rod up to far. Now I have to pull the spools and figure out what got loose (detent ball most likely). I have worked on stuff for the most of my life usually with good results, but it seems like everything I do of late gets bungled some way or another. Again Thank You for the great advice/info. By the way, nice dozer, nice shop.[/QUOTE]

 

[GuglioLS]

mcbike57,
I was wondering what was happening with your steering system troubleshooting and repair. Sounds like your got that under control. Are the steering case covers back on? If so I was wondering if you have any tricks getting that control rod hooked into the front break band fingers while at the same time threading the other end of the shaft through the tension adjuster AND while all that is happening suspending the case cover just enough so you can actually do all that and see its all going back together correctly? Ive done it 4 times (2 on each side) and that part never gets any easier. I am getting to be sort of an expert taking it all apart, rotating the tracks while unbolting the clutch / break drum bolts etc. The part i never look forward to is getting the case covers back on and have all the break linkages lined up. I fiddle with that part of it for hours, which is much longer than taking the entire system apart. Seems like the alignment of all the planets and stars needs to be just right for it to "fall into place". Holding your tongue just right while uttering a few choice 4 letter words and certain hand gestures has never made it any easier.

Bummer about the jacked up spool - sorry about that. Hopefully there is a screw cap cover that holds a detect ball and spring. I have no doubts you will get that corrected. Thank you for the compliments on my man cave.

Post some pictures!!!

 

[mcbike57]

Actually my shop mechanic installed the clutches and brake bands. Took the right side out first. Learning curve. Getting the brake bands hooked up was a bit of a trick. He hooked pin on the rod onto the front finger first. Sat top down and hooked the finger on the rear. Then the brake adjust rod was not thru the hole. Took a hooked prybar and hooked to the front pin and pulled the brake band back enough so as to start the adjuster nut on the rod. Left side was a little bit more of a pain because of fuel tank drain and something else that was in the way.
Pulled the spool off yesterday and pulled the spool rod out today. According to the breakdown I have there are supposed to be 2 ball bearings in the lower section that bolts on the bottom of the spool body. Took mine apart and only one ball bearing plus there seems to be fewer pieces in that same section on mine than in the breakdown. The three pieces indicated in your pic are where they should be and do not interfere with the movement of the spool rod. Could find no reason for the rod be stuck. Now I am afraid to put it back together until I can get some verification that it is correct or not. Oh boy!

 

[GuglioLS]

Yep sounds about right. Its a fishing expedition getting that break actuator put back together properly. It is literally doing 4 things at the same time and you can barely see if its all together correctly. I wound up tying a string to the rod to fish it through and used a bore scope camera to peek inside. I wonder how the factory ever put them together? A little Blue Smurf would sure come in handy. Glad at least that part is back together. Good luck with the hydraulic spool no doubt you will get that fixed up good as new. Keep us posted.......

 

[epirbalex]

Try and establish with certainty if there is second ball . Could do some expensive damage

 

[mcbike57]

Blocking past in the posts I found a link to k-part.com. Appears to be Russian? maybe? and found the parts that I think are missing. Rather than try to buy them from that site (accepts paypal) I have asked Darin Mitchell first via email contact and as much as I dislike doing so (as I am a small business owner and have received many inquiries similar to my own) I am going to call a Komatsu Dealer for the parts/advice/insight into this. Here we go

Try and establish with certainty if there is second ball . Could do some expensive damage

I did look very hard for the second/small ball. There is no way that it migrated into the spool body with the construction/assembly of the spool in its entirety. Have also closely examined the lower portion that should contain both balls. In the breakdown it shows the main ball loaded under a spring with the small second ball on the side? Where does this little jigger go exactly? Is it located in one of the holes that are aligned around the holder or is it located in the two aligned holes on the top portion of the holder. I am also missing two spacers which are located top and bottom on the big spring in this bottom piece.

Yep sounds about right. Its a fishing expedition getting that break actuator put back together properly. It is literally doing 4 things at the same time and you can barely see if its all together correctly. I wound up tying a string to the rod to fish it through and used a bore scope camera to peek inside. I wonder how the factory ever put them together? A little Blue Smurf would sure come in handy. Glad at least that part is back together. Good luck with the hydraulic spool no doubt you will get that fixed up good as new. Keep us posted.......

I am sure the factory business was figured out and had some neat little tools to take care of it.

 

[mcbike57]

Called Komatsu dealer in Louisville KY today. Parts guy was very friendly. Told me he did not know where the little ball bearing went or what its function was, he just sold parts. Ordered ball bearing and the 2 missing spacers. In the meantime Darin Mitchell had been trying to establish contact with me after I had emailed him about same. After playing phone tag we connected by email. Darin told me that there are actually three of those little bearings and they fit in the three holes that are evenly spaced around the body of the little piece. Smack forehead! Since I have worked on Japanese motorcycles, atvs and utvs for over 30 years I got a little drawer full of ball bearings. Quickly dug out three that fit the holes, but will further measure and make sure they are correct. The little bearings seem to work to center the piece they go in and the big ball bearing that fits inside is shoved in after a rather stiff spring. It seems to contact the little bearings to force them out to keep the piece centered. Now if I can figure out what the whole piece does? I think it has to do with blade float since there is no fluid actually going thru the piece. While it is frustrating to not be able to play with my new (to me) toy it is satisfying to get something sorted out right. By the way, the two little collars that were missing are apparently nowhere in the US. O D the parts guy in Louisville told me they would be on a plane out of Tokyo tonight. Also If you ever need Komatsu parts that have to come from Komatsu I recommend that you call the dealership in Louisville and ask for O D in parts. Anybody have any suggestions as to a good seat for this little dozer? Thanks.