Section for komatsu d20,21 and similar grey market dozers

[Terry Valentine]

"One side won't pull" sounds like the brake is jammed (possibly corrosion if it has been sitting). By "won't pull" do you mean the track will not turn? the clutch is normally engaged so that will not stop the track from turning, only will stop it from disengaging ! Describe symptoms in detail....

 

[sparke]

Terry
No it will turn I worked it for an hours thinking it might break loose the left side does not have power. I took the top plate off on that side and saw the adjustment for clutch but not sure which way to move screw.
thanks

 

[Terry Valentine]

So - summarize - is this correct? - your dozer goes round in circles because one track is not turning ? or does the engine stall ? I'm not sure which plate you took off, or which adjustment you are refering to ? Lets get this clear before you go any further. Explain every symptom and every action that you do - such as put in first gear, right track turns, dozer goes round in circles etc. I do not think it is clutch adjustment, but I need to be clear as to what you are experiencing before giving you further advice.

 

[sparke]

It goes stright unless you go up hill then it will go in a circle ,the plate I took off is the one on the back left that the brake lever goes into it has about 10 bolts that holds it on. The adjustment i'm talking about is the one that the hyd. piston moves thats under the cover.
thanks
jerry

 

[Terry Valentine]

It goes stright unless you go up hill then it will go in a circle ,the plate I took off is the one on the back left that the brake lever goes into it has about 10 bolts that holds it on. The adjustment i'm talking about is the one that the hyd. piston moves thats under the cover.
thanks
jerry

Previously you mentioned that "the lever on that side won't go down" - which lever ? First, it is unusual for a clutch to get stuck open - their normal position is closed. And you would normally be experiencing a slipping clutch long before it stopped working completely. The way I check mine is to put the dozer on blocks so the tracks can still turn. Then in a gear (either forward one or reverse one)(both tracks should be turning)pull the steering arm on each side until the clutch operates ( you will see the small piston on the clutch slave cylinder depressed) and not far enough to start the brake operating. The track should stop rotating. If in gear and no track turning then check that the slave cylinder is being disengaged - your links may be stuck.

If all links and slave cylinder seem ok (compare what happens on one side to the other when you pull a steering lever) but track is still not turning then check your clutch rotation with the cover off - you should see rotation coming from the bevel gear, but not being transmitted through the clutch pack - now make sure that your clutch is not being held open by the yoke (the big ring with arm that your slave cylinder act on, and has the clutch adjustment bolt and lock nut at the top) (if you are looking at the clutch pack then you have the top cover off so the slave cylinder will not be pressing on the yoke). If clutch us not being held open, and power is not going through it then this will confirm definatively that it is your clutch that has collapsed. The clutch plates can be rebonded to save cost. Specs are in the manual.

If you drive it on ground, then it can go straight until under load - like you experienced, but until you actually look at the transmission of power through the clutch you are not sure - it could be the pinion gear has shredded in the final drive - mine did once !

 

[sparke]

Thanks Terry
On the yoke clutch adjustment whitch way do you move the bolt to make sure clutch will be engaged. I would think you would shorten the distance from cly. piston.
thanks
jerry

 

[Terry Valentine]

Thanks Terry
On the yoke clutch adjustment whitch way do you move the bolt to make sure clutch will be engaged. I would think you would shorten the distance from cly. piston.
thanks
jerry

As the clutch is normally engaged, pushing the yoke against the clutch housing (by way of the slave cylinder piston being pushed out) opens the clutch - therefore moving the bolt away from the slave cylinder lets the yoke get pushed out to the limit of the clutch springs, giving the clutch maximum compression / engagement.

 

[1stkom]

Hey Countryboy, as a new member I clicked on the "NEW MEMBERS" red lettering to private message you to ask how to put a photo under my "new member" name and it sats I don't have privilages. How otherwise do I contact you for this info?

 

[jearl]

I have a d 21a-6 with bad cluches how bad of a job is it and does ony one have a shop manual.

 

[mitch504]

jearl, look back a couple of pages, there is a link to a downloadable manual that works well.

 

[buck29]

Great site. 1st time dozer owner,with no manual yet. Couple ?'s. D21p-7 When you first start up no steering to the right until it seems to warm up. The more it runs the better it gets. I'm going to check steering adjustments. When you pull steering to the right it seems to have no resistance. Also when running dozer across open ground motor will sputter (react) to ground roughness.

 

[dblaneyfan]

Great site. 1st time dozer owner,with no manual yet. Couple ?'s. D21p-7 When you first start up no steering to the right until it seems to warm up. The more it runs the better it gets. I'm going to check steering adjustments. When you pull steering to the right it seems to have no resistance. Also when running dozer across open ground motor will sputter (react) to ground roughness.

Welcome buck,

Below is a link to a Komatsu D21P-7 (also D20P-7, D21A-7, D21S-7) service manual. Maybe this will help a little.

http://min.us/mLNVKfJwU#1o

Best,

J

 

[byrdrich]

I have a very similar problem with my d21p6 . I replaced the steering clutches last summer.Every thing was working perfectly until I started to use it this week. It worked great two weeks earlier. Now it turns to the left but when I try to turn to the right it does nothing, the engine does not seem to lug down. it is if the left track isn nor turning. I hane taken the seat floor board etc off, and it seems that all the visible linkages are the same left and right. any help or advice would be greatly appeciated.

 

[byrdrich]

answer to my own Question

I finally decided to back my ears and dive in, I pulled the left clutch assembly. Three of the clutches had lost the lining, no indication of exesive heat.
Oh well , I have some new ones on the way. This time I will pay more attention to the instructions in the manual,along with the specs.
By the way this is a great forum, and I have learned a lot from it over the last year when I traded aHarley for my D21P6.

 

[g_man]

It will be interesting if you can figure out what happened. Keep us posted. I too am learning here.

 

[Southbasin]

Hi all. New to this forum. I've read the thread from start to finish and learned alot. It is really nice to know there are so many helpful people out there. I really appreciate everyone's contributions. I've always had larger dozers for ranch use, but no longer have the ranch or need for the equipment. I now have a d21A-7e with about 1000 hrs that I bought 2 years ago. Successfully completed the 1k service without incident.

I have had a starting problem. The "safety module" seems to have failed. A replacement was about $500 so I bypassed it with direct wires to the solenoid (with a cut-out). I would like to make it right though. Can the "small box" attached to the safety module be replaced without compromising the other functions of the safety module?

FYI I thought this was a solenoid problem and replaced such with an after market one for about 1/3 the Komatsu price.

 

[byrdrich]

g man; Just thought i'd let you know about that clutch problem. There was some of the clutch lining missing from two of the plates and all from another. I finally got it back together and it works(with new clutches of course). This job is not all that difficult if you take your time and don't get flustered. I got a set of manuals with the dozer. They must be photo copies, since you have to have a
pretty good imagination to use the pictures, and some of the good to know info is let out of the text.

 

[g_man]

Thanks for the update- I'm alittle slow, sorry. Why do you think your clutches wore out so quick since replacing them last summer /

gg

 

[cah8989]

My question is do I access the stering linkage thru the floor panel or the rear sear area panel to adjust the steeering linkage??

 

[cah8989]

I was also checking to see if anyone would have a guess on what a d20p-6 with about 1800 hours on it?? I am thinking about selling it. Its a great machine dont have muchuse for it much anymore.