Section for komatsu d20,21 and similar grey market dozers

[Frank Dozer]

Hello Fred
Thanks for the advice !! Have you ever used heat? Such as an acetylene torch and heated the cylinder at the base of the adjuster and backed it out?
Frank

 

[kc5gxc]

Hey Frank
Those things can have lots of pressure on them. You should back it out about 1/2 turn and the pressure will release from the lower part of the special valve/fitting.
If you break it off, it may fly out with great force.
These grease fitting/valves can be ordered. I got mine from Heavyquip.
Take care
Pete

 

[treefarmer]

Still hoping for a reply about how to properly measure the fluid level in the transmission as I don't have the operater/maintenance manual. Does it need to be warmed up? I know it sounds like a mundane question. But it's reading low when running and overfilled when shut down. D21A-6

Sam

 

[treefarmer]

That is for a D21A-6 on the previous post.

Sam

 

[Frank Dozer]

Fluid level in the transmission...

Sam,
I have a D21A-5. In my operator's manual this is what it reads:

CHECK BEFORE STARTING

I check my fluids before I start my dozer every day.

Hope this helps,
Frank

 

[treefarmer]

Frank,

Thank you. That's exacly what I need to know. Will drain some fluid off. Not sure what impact it will have if any. I do know that the the fluid is drawn from the transmission for the circuits which includes the steering valve.

Regards, Sam

 

[Frank Dozer]

Greasing The Track Adjusters.......

First of all, I'd like to say a Thank You !!! to Pete for the excellant picture of his dozer with homemade ROPS. If you don't mind, I'm going to copy it to my dozer.
Now, I have a ( hopefully not ) :Banghead problem. My dozer is a Komatsu D21A-5, and the track sag ( Regular tracks, not rubber or swamp tracks ) is 2.5 inches. So I tried to use my grease gun to get the required 1.5 inches of sag per the owners manual. The grease fittings won't take grease. Grease just squirts out around the grease fitting to grease gun connection. I then tried to remove the fitting, but it's really rusted on to the cylinder. Does anyone have any ideas on how to remove the fitting? Heat, ballpean hammer, etc........... Also, I guess I have to remove the 2 small bolts that hold the grease fitting protector. I'm going to soak them with PB Blaster until I decide :beatsme what to do...Has anyone else had this happen and how did you resolve it ?

Frank

Hello Forum,
Well, I still can't get the adjusters to accept grease. I push in the ball on the fitting and a small amount of grease squirts out. I have soaked the fitting with PB Blaster, but it won't turn, and I don't want to use muscles on it in fear that I might snap it off. The nipple has been reduced in overall diameter, due to rust from not being cleaned off over the years. I also don't want to use heat because of different reasons. I was thinking, is there a tool that can go over the old nipple and extend to a new grease fitting? Maybe a grease hose with a clamp to a new fitting?
Any thoughts???
Frank

 

[kc5gxc]

Hi Frank
All I can tell you is that on mine, I had no cover....long since gone.
One of the grease adjuster fittings was so rusted, it would not take grease due to the fitting being worn out and rusted out of shape. (I could hold the grease gun on hard and get some grease into it)
I unscrewed the whole fitting about 1/2 turn to 3/4 turn I think....and the pressurized grease came out of the lower part to relieve the pressure the spring had on it. It unscrewed fairly easily. (with a wrench)
When the pressure releases, the spring contracts and slack appears in the track, as the idler wheel comes back to the rear a bit.
I installed a new fitting assembly and was back in business. The fitting was only a few bucks.....
You got the new one yet? If so,the people who sold it to you should be able to tell you some info on replacing it !!!
Heat on that area may not be a good idea...but I would check with somebody that knows about that more than me.
Good Luck
Pete/MS

 

[scokat]

Track Tension

I recently replaced the grease fitting for the track tension, wouldn't accept grease. Did the hot rod trick-no luck, bought the oil injector hammer to clear it out, no luck. So can anyone explain to me how to take this apart and repair this. Does the track have to come off, if so how? Also How do I take the tensioner off with that huge spring. I know there must be a trick to it, it looks like one unit. Any help is greatly appreciated.

scott:Banghead

 

[kc5gxc]

Hi Scott
You gotta have room left for the piston and rod to move forward. It may be fully extended if the tracks, etc...are worn. You can look at the forward rails in front of the idler. On mine, I got about 2" of rail left that the idler can move forward.
As far as removing the spring....it's pre-compressed and can kill people if it gets loose. You would need to know exactly what to do to remove it, and maybe some kind of compression tool.....I have never messed with one, so don't know. I have just been warned about it.
Let us know how you come out. I may have to remove springs one day.
Good Luck
Pete

 

[mikek]

as kc5x said, if you are at the end of track tensioning travel, the piston that the grease is pushing will be bottomed out, no more grease will pump into the fitting.

if thats the case, I suppose its time for chain$ roller$ and $prockets.

I rebuilt the tens. cyl. on my machine (posted a while back in this thread). Mine would pump up and tens. the track, but in an hour of operation the track would be slack again.

You don't need to take the track off the machine but the job is made a WHOLE lot easier if you open up the tensioning grease fitting and allow(or force) the piston/cylinder to fully retract, giving you 6-8 inches of sag in the track. A comealong and chain are handy to hold the slack track out up out of the way.

I has to use a torch and WD40 on many of the bolts to get them out, replaced with new ones from local hardware store.

The spring section does not need to be dissassembled to do this job, and you DO NOT remove the bolts that capture the spring.

Working on dozers is hard dirty work (I'd rather be spinning wrenches on AMA Superbikes) but I figure we all accepted that when we bought these little Komatsu's.

 

[Digger145]

as kc5x said, if you are at the end of track tensioning travel, the piston that the grease is pushing will be bottomed out, no more grease will pump into the fitting.

if thats the case, I suppose its time for chain$ roller$ and $prockets.

Just have a look at the front forks where the wheel idler slides, any room left to go forward?

If not and the bushes in the chains haven't worn right through to the pins, consider just dropping a link. I.E. shortening the track chain by one link, to get a bit more life out of it.

That's what we did on our BD2G and the 15 Ton digger. The dozer is still going, but we are having to do a chain on the excavator ATM. It does a lot more work than the dozer and we did get an extra 14 months out of the chain.

If you can weld, hard facing and rebush the wheel idlers when reusing old chains is the go to. Don't choose the highest grade hard facing, it will be too brittle.

If you need new undercarriage do it all at once, try not to mix new stuff. The trick is to try and make everything die at once. LoL

 

[scokat]

as kc5x said, if you are at the end of track tensioning travel, the piston that the grease is pushing will be bottomed out, no more grease will pump into the fitting.

if thats the case, I suppose its time for chain$ roller$ and $prockets.

I rebuilt the tens. cyl. on my machine (posted a while back in this thread). Mine would pump up and tens. the track, but in an hour of operation the track would be slack again.

You don't need to take the track off the machine but the job is made a WHOLE lot easier if you open up the tensioning grease fitting and allow(or force) the piston/cylinder to fully retract, giving you 6-8 inches of sag in the track. A comealong and chain are handy to hold the slack track out up out of the way.

I has to use a torch and WD40 on many of the bolts to get them out, replaced with new ones from local hardware store.

The spring section does not need to be dissassembled to do this job, and you DO NOT remove the bolts that capture the spring.

Working on dozers is hard dirty work (I'd rather be spinning wrenches on AMA Superbikes) but I figure we all accepted that when we bought these little Komatsu's.

Mike,

can you send me an email ([email protected])and any pics on what bolts to take off to get the spring assembly off and the piston out. My tensioner has about 2 inches of travel it can move forward, and the chains and sprockets are good. The yoke /piston wont move forward or back. I talked with the dealer I bought it from and he said he has used a excavator to push and pull them before to get them unstuck. He asked another dealer who said to used a porta power and try and move the piston to get it unstuck. Any info you can give on how you did yours would be helpfull.

thanks
scott:usa

 

[Digger145]

...... My tensioner has about 2 inches of travel it can move forward, and the chains and sprockets are good. The yoke /piston wont move forward or back.

Will the front idler compress back onto the spring at all? Drive up slow on a firewood round / log and it should slide back a bit on the recoil spring. It should be functioning separate to the track tensioner (grease part).

I wonder if you have a broken recoil spring and it's fouling inside on the housing. If that was the case, the track tensioner could be pushed out as far as it would go, yet not transferring the movement through the spring. Forcing it would only make matters worse if that was the case. Check the spring is working.

If you can't raise the blade and drag the wheel idler forward (inline or straight) with a car and a bit of chain, then it's too stuck IMHO. I only say this because there has to be a piston seal for the grease and you a going to stuff it, by dragging it over the "stuck area", be it rust or whatever. See my point?

 

[H8TPVMNT]

Hey guys. Noob here. I'm looking at a D21P-7 with the joystick steering. What is your opinions between the joystick or the "two stick" (sorry don't know proper terminologyointhead) as far as reliability and ease of operation. Thanks in advance.

 

[Digger145]

Hey guys. Noob here. I'm looking at a D21P-7 with the joystick steering. What is your opinions between the joystick or the "two stick" (sorry don't know proper terminologyointhead) as far as reliability and ease of operation. Thanks in advance.

I haven't seen one of these, got any pics?
I guess it would have hydrostatic drives at the sprockets much like a bobcat (skid steer) does. Just a guess though.

The two stick type are all brake steer as far as I know. Pull the lever or stick and it takes the drive away from that side (clutch packs) and applies the brake to that side, drive continues on the other side providing turn as you know.

 

[H8TPVMNT]

I haven't seen one of these, got any pics?
.

I do have a pic but need a couple more post' to post them. Theres one down.

 

[Digger145]

I do have a pic but need a couple more post' to post them. Theres one down.

Don't ya hate that. This might help.

Tell us a bit about the dozer you are looking at buying.
How much $$$ is it? How many hours? Have you read back through the thread(s) to get an understanding of undercarriage life and how wear presents and there-by inspect what you are buying?

 

[H8TPVMNT]

Don't ya hate that. This might help.

Tell us a bit about the dozer you are looking at buying.
How much $$$ is it? How many hours? Have you read back through the thread(s) to get an understanding of undercarriage life and how wear presents and there-by inspect what you are buying?

The one I'm looking at is a 1993 D21p-7 w/1900 hrs asking $17,500. I have read the entire thread and do expect to have to put some money in undercarraige at some point. The dozer will be used for some light brush clearing at deer camp. I just haven't seen many joystick steering rigs to get a feel on it's reliabilty. Pics to come later.

 

[Digger145]

Has anybody mentioned to have a close look at the dash screws? Try to see if the instrument panel cover has been removed to jigger with the hour meter.