-
Thank you for visiting HeavyEquipmentForums.com! Our objective is to provide industry professionals a place to gather to exchange questions, answers and ideas. We welcome you to register using the "Register" icon at the top of the page. We'd appreciate any help you can offer in spreading the word of our new site. The more members that join, the bigger resource for all to enjoy. Thank you!
Section for komatsu d20,21 and similar grey market dozers
- Thread starter rangerfreak
- Start date
I adjusted the linkage and still no steering.I'm thinking maybe there's air in the steering cylinders?I'm thinking while I have it apart I would clean (Or replace) the transmission filter I'm sure it hasn't been looked at.Do I clean this or replace it? And is there a bleed screw for the steering cyl.Or do they bleed themselves?I haven't really ran it much since having it all apart maybe 5 mins.
DJK
Well-Known Member
Back them off another 3 turns.
RRRancher
Well-Known Member
I don't know a thing about the transmission filter. Sorry. When I had the leak I mentioned in a previous post, the clutch oil would slowly leak out until it got so low that the steering clutches wouldn't release. There was not enough oil to actuate the pistons that release the clutches. All I had to do was refill it with oil and the steering worked again just fine. I'm not saying you don't have to bleed anything, as I don't know for sure. But I didn't have to after refilling the clutch oil, and I don't see anything in the dis-assembly/reassembly instructions, or in the maintenance instructions about bleeding anything.
Here are some thoughts. If the dozer drives forward and reverse, it is obvious that the clutches are both engaged. Until one of the clutches disengages, you will not turn. Even without a steering brake being engaged, the dozer will turn gradually in the direction of a disengaged clutch, assuming you are on level ground. The brake on that side only increases the turn rate. I'm not sure how you would confirm that you have oil going to the pistons that disengage the clutches. I'm assuming you verified that the plungers are being pushed in when you pull back on the steering handles.
As I mentioned earlier, if you do not have enough fluid in the clutch fluid tank, you will never disengage the clutches. The clutch fluid dipstick is the one under the main clutch pedal. Make sure it is at least touching the dipstick, and preferably in the crosshatched area of the dipstick. If that is ok, and the plungers are being depressed, I don't know what to tell you to do next. I will tell you that if you have the brake band too tight, it will try to stop the rotation, while the steering clutch will try to rotate it, causing the engine to bog down. Good luck with it.
EDIT: I was just looking at the Operation and Maintenance manual and realized for the first time that the D21 doesn't show a main clutch case and fill tube/dipstick. Now I'm not sure what feeds oil to your steering clutch cylinders. I would guess it comes from the transmission case. And the filler tube/dipstick under the main clutch pedal is for the transmission case on a D21, whereas it is for the clutch case on a D20.
I also found the procedure for the transmission strainer. It does say to remove and clean it, but if it is broken or damaged to replace it. Sorry for the confusion.
Here are some thoughts. If the dozer drives forward and reverse, it is obvious that the clutches are both engaged. Until one of the clutches disengages, you will not turn. Even without a steering brake being engaged, the dozer will turn gradually in the direction of a disengaged clutch, assuming you are on level ground. The brake on that side only increases the turn rate. I'm not sure how you would confirm that you have oil going to the pistons that disengage the clutches. I'm assuming you verified that the plungers are being pushed in when you pull back on the steering handles.
As I mentioned earlier, if you do not have enough fluid in the clutch fluid tank, you will never disengage the clutches. The clutch fluid dipstick is the one under the main clutch pedal. Make sure it is at least touching the dipstick, and preferably in the crosshatched area of the dipstick. If that is ok, and the plungers are being depressed, I don't know what to tell you to do next. I will tell you that if you have the brake band too tight, it will try to stop the rotation, while the steering clutch will try to rotate it, causing the engine to bog down. Good luck with it.
EDIT: I was just looking at the Operation and Maintenance manual and realized for the first time that the D21 doesn't show a main clutch case and fill tube/dipstick. Now I'm not sure what feeds oil to your steering clutch cylinders. I would guess it comes from the transmission case. And the filler tube/dipstick under the main clutch pedal is for the transmission case on a D21, whereas it is for the clutch case on a D20.
I also found the procedure for the transmission strainer. It does say to remove and clean it, but if it is broken or damaged to replace it. Sorry for the confusion.
Last edited:
DwayneC
Member
I'm a fairly decent mechanic but have very little experience with Komatsu. I'm working on a D20P for a friend. He's an older guy and not very mechanical. He's developed a bit of an oil leak which dropped the oil level far enough that while working on a bit of a side hill the oil pressure light came on. He didn't really know what it was, thought it was for the alternator and ignored it, kept on working...till there was a sort of bang. He shut it off right away and found that the oil fill cap on the top of the valve cover and dipstick had both been blown out of the engine.
He called me and I came up to look at it. Found the dipstick, checked the oil and found it didn't read on the stick. We added oil and cautiously started the engine. It sounded decent but had a light knock, more like a tappet noise rather than a rod knock. The oil light was now out so we knew it had some oil pressure. It was in a bad spot and we knew we'd have to get it down the hill to the house, especially if the engine had to come out. We ran it at just above idle for about 10 minutes while driving it down the hill, the knock would sort of come and go and the oil pressure light stayed off the entire time.
A few days later (yesterday, in fact) I had a chance to check it out a bit. I removed the oil pressure sending unit and installed a gauge, then started the engine. It sounded good with only a very slight tapping, more from the top of the engine than the bottom. I didn't really hear the knocking we were hearing the first time. The oil pressure was about 40 psi at cold idle but shot up to about 70 with a few more RPMs. I went over it pretty good with a stethoscope trying to pinpoint the source of the tapping. I adjusted the valves which were all slightly loose but not bad, none were loose enough to account for any real noise. I didn't really expect it to help anyway.
On restarting it sounded about the same. After a bit of running, varying the engine speed a bit it finally started to knock again like before. It comes and goes according to engine speed and sounds to me like a wrist pin. I would expect the problem to be bearing damage, not wrist pin. The oil pressure seems very good, after it's warmed up it settles down to about 40 at idle and 50-60 at a bit higher RPM.
I suspect I'm just going to have to tear into it. He'd like to run it as-is but I think I've got him discouraged from that. I guess I'll pull the head to start, I presume I can drop the pan with the engine in place? I figure to inspect bearings and crank as well as wrist pins and hoping I can do that with the block still in place, if the crank needs work then obviously the engine will have to come out.
Anyone have a good source for engine parts? What about a good used engine if it come to that? Thanks in advance...sorry for the mini-novel!
He called me and I came up to look at it. Found the dipstick, checked the oil and found it didn't read on the stick. We added oil and cautiously started the engine. It sounded decent but had a light knock, more like a tappet noise rather than a rod knock. The oil light was now out so we knew it had some oil pressure. It was in a bad spot and we knew we'd have to get it down the hill to the house, especially if the engine had to come out. We ran it at just above idle for about 10 minutes while driving it down the hill, the knock would sort of come and go and the oil pressure light stayed off the entire time.
A few days later (yesterday, in fact) I had a chance to check it out a bit. I removed the oil pressure sending unit and installed a gauge, then started the engine. It sounded good with only a very slight tapping, more from the top of the engine than the bottom. I didn't really hear the knocking we were hearing the first time. The oil pressure was about 40 psi at cold idle but shot up to about 70 with a few more RPMs. I went over it pretty good with a stethoscope trying to pinpoint the source of the tapping. I adjusted the valves which were all slightly loose but not bad, none were loose enough to account for any real noise. I didn't really expect it to help anyway.
On restarting it sounded about the same. After a bit of running, varying the engine speed a bit it finally started to knock again like before. It comes and goes according to engine speed and sounds to me like a wrist pin. I would expect the problem to be bearing damage, not wrist pin. The oil pressure seems very good, after it's warmed up it settles down to about 40 at idle and 50-60 at a bit higher RPM.
I suspect I'm just going to have to tear into it. He'd like to run it as-is but I think I've got him discouraged from that. I guess I'll pull the head to start, I presume I can drop the pan with the engine in place? I figure to inspect bearings and crank as well as wrist pins and hoping I can do that with the block still in place, if the crank needs work then obviously the engine will have to come out.
Anyone have a good source for engine parts? What about a good used engine if it come to that? Thanks in advance...sorry for the mini-novel!
RRRancher
Well-Known Member
TigerDan, sounds like your friend dodged a very expensive bullet there, and with the tapping sound still coming from it, the bullet may ricochet and come back anyway. Hopefully it turns out to not be anything serious.
If you are looking for parts, I posted back on page 115, message 1712 that we have a full service Komatsu dealer here in our area. Waukesha-Pearce Industries is their name and this branch is located in Kilgore, Texas. The headquarters is in Houston. They are some very nice folks and should be able to supply you with anything you need. Their website is [URL="http://wpi.com"]http://wpi.com[/URL].
Also, there is a guy who posts on here from time to time who carries some parts for these dozers. He goes by the handle of darinray. I don't know if he has any engine parts or not, but you can contact him via his website at http://dmmsales.com.
Good luck with it.
If you are looking for parts, I posted back on page 115, message 1712 that we have a full service Komatsu dealer here in our area. Waukesha-Pearce Industries is their name and this branch is located in Kilgore, Texas. The headquarters is in Houston. They are some very nice folks and should be able to supply you with anything you need. Their website is [URL="http://wpi.com"]http://wpi.com[/URL].
Also, there is a guy who posts on here from time to time who carries some parts for these dozers. He goes by the handle of darinray. I don't know if he has any engine parts or not, but you can contact him via his website at http://dmmsales.com.
Good luck with it.
Last edited:
Okay RR Rancher this is what I found the adjustment on the clutch yoke that the steering cylinders push against needed adjusted out.Now when you pull the steering levers the clutch disengages. But I have no brakes yet.I think can adjust them also.Thanks again for all the help.Looking forward to trying this machine out. By the way I noticed your machine has rubber tracks.If I switch to Rubber from steel does the sprockets need to be changed or the rollers?Looking forward to any replies!
RRRancher
Well-Known Member
Dozman, that was not my dozer. It was a picture I found on a web page. I have a D20A-6 with the standard metal, non-pyramid tracks.
Ok, so now you have the clutches disengaging. That's great. I think all you need to do now is tighten up the bolts on the steering brake bands. If you tighten one too tight, the brake will be engaged while the clutch is engaged, which is not good for the long term, but won't hurt temporarily. If it is just slightly too tight, you will smell it heating up, and possible smoking, as the band is always rubbing against the clutch pack. Know how I know?
If it is way too tight, the engine will bog when you release the main clutch as the steering clutch will be trying to turn the clutch pack with the brake band trying to stop it from turning. It shouldn't take long to get it just right. If it were me, I would tighten the bolt on one side only about a turn at a time and then try turning with the handle all the way back until you get a completely stopped track on that side and a quick turn. You might even then back it off a half turn to see if it still does, just to make sure the band is just tight enough, but not wearing all the time. Then repeat for the other side. I think you are just about to have it steering as it should. Good luck.
Ok, so now you have the clutches disengaging. That's great. I think all you need to do now is tighten up the bolts on the steering brake bands. If you tighten one too tight, the brake will be engaged while the clutch is engaged, which is not good for the long term, but won't hurt temporarily. If it is just slightly too tight, you will smell it heating up, and possible smoking, as the band is always rubbing against the clutch pack. Know how I know?
If it is way too tight, the engine will bog when you release the main clutch as the steering clutch will be trying to turn the clutch pack with the brake band trying to stop it from turning. It shouldn't take long to get it just right. If it were me, I would tighten the bolt on one side only about a turn at a time and then try turning with the handle all the way back until you get a completely stopped track on that side and a quick turn. You might even then back it off a half turn to see if it still does, just to make sure the band is just tight enough, but not wearing all the time. Then repeat for the other side. I think you are just about to have it steering as it should. Good luck.
JRGCUMMINS
New Member
I have a D21A-6 for use around the farm. I know the steering topic is very popular on these dozers, but I've run across a problem that I can't quite get my head around. On flat ground or downhill the dozer will not steer right (whether under load or not), the left brake always works fine. When the dozer is going uphill the right brake works perfect. When both levers are pulled back the dozer stops just as it should. No bogging down, grinding or anything like that. What would cause the right brake to work properly only when the dozer is climbing a hill? And to work when stopping the dozer by pulling both levers back but will not work alone to turn the machine on flat ground?
I tried to adjust the brake band but the 17mm adjustment bolt is locked up tight on the right side...tried everything. Left side adjustment turns just as it should. Adjusted or not, it works fine going uphill. What am I missing here? I am looking for any suggestions before I bust into the machine this weekend. I appreciate any help.
I tried to adjust the brake band but the 17mm adjustment bolt is locked up tight on the right side...tried everything. Left side adjustment turns just as it should. Adjusted or not, it works fine going uphill. What am I missing here? I am looking for any suggestions before I bust into the machine this weekend. I appreciate any help.
mitch504
Senior Member
sounds like your right brake isn't working. when you pull the right handle, it is opening the clutch, and gravity is stopping that side of the tractor when you are climbing a hill. When you pull both, it opens both clutches.
JRGCUMMINS
New Member
Ahh, didn't think about gravity. That makes sense. Thanks for the reply.
Hello all, I have a d21a-7. When I first start out my right steer is sluggish, and not responsive. The left is fine. The machine is a pilot control for steering and drive. If I run the dozer about 100 yards, and attempt some turns, it will start to react properly, even better in high range. This dozer sat for about a year before I purchased it. All fluids are good, all linkages are lubed and seem fine. Is this some indication of a bigger problem about to start? Any ideas??
tpitt
Well-Known Member
Just purchased a D21a yesterday. Less than 800hrs. Serial # is 78529. Any Idea what year it is? It's in excellent shape, with rubber tracks. Hoping to get a lot of use out of it. Thanks, Terry
Dozman,
If you replaced the steering clutches in your dozer do you think you got the brake bands hooked good when you put it back together, I had a lot of trouble hooking mine and I had to go back in and hook one of them. Hope everything works out good for you .
If you replaced the steering clutches in your dozer do you think you got the brake bands hooked good when you put it back together, I had a lot of trouble hooking mine and I had to go back in and hook one of them. Hope everything works out good for you .
darinray
Charter Member
Dozman- Did make sure the actuating arm is IN the brake band dog ear... If you don't have that in there you can tighten down all you want and won't have any brake... Hope this helps and I didn't read all of the replies so if this has already been discussed then OOPS.
darinray
Charter Member
darinray
Charter Member
JRGCUMMINS- IF your right side isn't actuating without adjusting then you have to get that nut to move... IF you break it I have more for you but would recommend penetrating oil on it with a big cheater bar.. I've had them stuck to the point where I put a 4' cheater bar and it backed off with noise.. Either way it has to move or break then you get to tear into the housing to fix it... Good luck..
Either way it has to move or break then you get to tear into the housing to fix it... Good luck..
darinray
Charter Member
Dwbinc.. Nah no major trouble just tighten the brake band...Not much because it works after it's warmed but a tweek will do.