Clutch question - Komatsu D20

[KomatsuD20A]

hi folks - my first post and let me say:

:notworthy

Glad to be among so many folks who know heavy equipment...

I on the other hand, don't know heavy equipment...I have been running a little farm dozer, a Komatsu D20A, for a couple of years now.

A recent problem I noticed is that when I push the clutch pedal all the way in, the drive shaft keeps spinning. I see there is a collar type brake to stop the shaft, but I suppose it is not stopping it. The result is when I try to put it in gear, the gears grind till the grinding stops the shaft from turning:eek: ...:Banghead
Does this sound like to you that my clutch linkage is just out of adjustment? When I let off the clutch, it takes off with plenty of power, no clutch slippage.


Also - I noticed the head has a hairline crack that is leaking antifreeze...will this just get worse till it ends the usage of the head, or is it controllable with stop-leak product?

Thanks for the help!!!

[Steve Frazier]

Welcome to Heavy Equipment Forums!!:drinkup

I'm not familiar with your particular clutch set up, but typically the clutch brake should prevent the problem you're having. It would either need adjustment or replacement to regain function.

As for your head leak, the answer is yes.:wink2

You may be able to control the leak with a leak preventing product, but it may be only temporary. I don't like using them because they can also clog small passages in radiators as well. Some cracks will not grow, others will. In the event that this one continues to grow, repair or replacement of the head will be required.

[Orchard Ex]

Like Steve said there is an adjustment for the clutch brake. Try to find a manual for it on EBay etc. Komatsu did a very good manual for the 20/21's. All the adjustment procedures are in there. PM me if you can't find one and I'll see if I can help.

[KomatsuD20A]

Thanks guys - Orchard, you have one also, right? I'd love to talk about it with you, what problems/surprises have you encountered? How much was your manual?

[Orchard Ex]

Mine is a D20A-6 model. To be honest I really haven't had any problems yet - Knock on wood. Just normal maintenance. It can be a pain to cross reference filter numbers as NAPA and our other local parts stores only have a fuel filter listing. My nearest Komatsu dealer is 2 hours away. The engine is Yanmar so if you have a Deere dealer nearby sometimes they can help with stuff too. Most all of the undercarriage parts are available from a good track shop at normal prices.
My manual is a copy made by the dealer that I bought the dozer from. No idea what one should cost.
BTW - the manual's spec for the clutch brake is 2.5 - 3.5 seconds to stop the clutch after you depress the clutch pedal. If it's longer loosen the locknut and adjust the brake.

[KomatsuD20A]

Hey Orchard, I need to replace a light bulb and my system, like yours I imagine, is 24 volt. I can't find a 24 volt bulb anywhere I have looked...how did you deal with this? thanks.

[digger242j]

There are lots of different models of equipment out there with 24 volt systems. You don't say whether the bulb you need is peculiar to your machine, or to Komatsu, so I'd suggest trying any nearby equipment dealership. Chances are, whatever brand they carry, they'll have parts for something that has a 24 volt system.

[Steve Frazier]

If you get the number from the bulb, your NAPA dealer should be able to order it for you.

[Orchard Ex]

Hey Orchard, I need to replace a light bulb and my system, like yours I imagine, is 24 volt. I can't find a 24 volt bulb anywhere I have looked...how did you deal with this? thanks.

Depends on which bulb. I need to replace the charging system "idiot light" on the dash but haven't gotten around to it yet. I will do what Steve and Digger mentioned and take the old one with me to our parts places.
If you mean one of the work lights. I have resigned myself that when it's dark it's time to go home. :)
FWIW - I need a couple glow plugs, Komatsu wants $46.50 ea.:eek: I'll pull one and take it to NAPA and Deere with the part number and see if they can cross reference it.

[Jeff D.]

FWIW - I need a couple glow plugs, Komatsu wants $46.50 ea.:eek: I'll pull one and take it to NAPA and Deere with the part number and see if they can cross reference it.I hate to go steering this off course but, when I went to get glow plugs for my Bobcat they asked me if I wanted 10.5volt or 12 volt. I thought that was odd, but said 12volt, since that was what my battery was. I later found out that lower voltage glow plugs will sometimes be installed to lessen the time it takes to heat them up. But, there's a greater chance of burning them out when doing that if they're on too long. I guess GM uses different voltage plugs in their 6.2 and 6.5 engines, down to 6volts.

I should've chose the 10.5 volt plugs cause I have lean on the glow plug switch for about 15 seconds before she'll light up now.:Banghead

When I drove vehicles(motorcoaches)with 24volt electrical systems I was able to get the bulbs at big truck repair shops, when on the road. They always had them in stock.

[Countryboy]

Atleast you don't have to look for 52 volt bulbs.:spaz Thats what locomotives use.

[Orchard Ex]

I hate to go steering this off course but,
Sure you do....:yup
When I had a 7.3L 1 ton the guy before me took out the GP timer and installed a push button. Any time somebody else drove it it would come home with 8 burnt out glow plugs. :mad: A switch from 6v to 12v solves that problem, but yeah you have to hold the button twice as long.

If you really really really get stuck looking for 24v bulbs, try an aircraft supply house like Aircraft Spruce & Specialty - But be ready for sticker shock.

[544D10]

I had my glow plugs on a toggle switch on my military truck that was unlabeled, sure kept any yahoo's from stealing your rig.

[KomatsuD20A]

Hey guys, thanks and I will check out NAPA, the one place I failed to check! By the way, my water temperature guage has not worked ina while, (orchard, I'd liketo say that's wat contributed to my cracked head) I figured it was a sending unit, but i'm not sure. I followed the wire from teh guage to the block, and it is not severed or damaged. Can I assume it is a sending unit failre and change it out? as long as I'm going to NAPA I can do that, what do youguys think? thanks again.

[Jeff D.]

Can I assume it is a sending unit failre and change it out? as long as I'm going to NAPA I can do that, what do youguys think? thanks again.It might be the sending unit, but it's also often the gauge that's bad instead. When I've had electrical gauges quit working more times than not it's the gauge that's the problem. I think the vibration damages the internals, while sending units usually don't have much in the way of moving parts inside to get damaged.

The gauge has too match the sending unit with respect to it's range of resistance variation. It would be hard to tell if the sending unit or gauge would work with a replacement without buying it specifically for your machine.Not every temp sending unit uses the same ohm range.

The gauge would also need to be a 24volt unless it has a voltage reducer in the system. You could purchase a mechanical temp gauge from Napa that doesn't require any electrical connection. It reads by the changing pressure in a bourdon tube created by its heating at the sending unit. They are simple to install IF you can get the correct adapter to fit your metric engine.(which you should)

A mechanical gauge is pre assembled so you need to run the flexible bourdon tube through the dash hole and route it to the engine without disconnecting it from the gauge.

Good luck what ever way you decide to do it.:yup

[Orchard Ex]

By the way, my water temperature guage has not worked ina while, (orchard, I'd liketo say that's wat contributed to my cracked head) I figured it was a sending unit, but i'm not sure. I followed the wire from teh guage to the block, and it is not severed or damaged.

What Jeff said plus:
(You may have already done this) Don't forget to check the fuses before you go replacing stuff. I've had them stop making good contact from vibration and moisture even if they aren't blown so take them out and clean up the contacts and read both sides with a meter to make sure you have power flowing through to the gauge.

To me the $64 question is why is it overheating enough to crack a head?
Once you get a gauge sorted out - that's gonna be the question. Maybe start thinking about a radiator flow check or a water pump?:beatsme

[KomatsuD20A]

OK - I'm back - the clutch brake was an easy fix. It is adjusted with a bolt tensioner that is held in place by two nuts. I broke them with a wrench, then just finger tightened them nearly all the way down. After the adjustment, when I press in the clutch pedal, the shaft stops within about 3 seconds. (I think the standard is 3-5 seconds) That I had to tighten it almost all the way probably means I need to order a new brake pad, but i tlooks like it would be an easy repair to replace it. Thanks for the tips everyone!

[johnmcdougall]

Interested in the clutch on my D20A-6. The pedal is no longer returning to fully up position ( engaged ). I see only 1 spring that is vertical, connected direct onto the final lever going into bell-housing. I tried adjusting the length of the rods, but this made it worse. When I lift the clutch up fully it stays there and operates fully. I cannot see where another spring may have been or is broken. Apreciate any help.
Regards John

[darinray]

There are 2 little bearings that the clutch linkage rides on that get seized up. It is the bracket mounted on the side wall of the dozer right under the floor plate by your feet. There are 3 linkages connected to it. May try some penetrating fluid but it's not my luck to have it something simple like that and end up taking it aparts and replacing with new bearings. :)

Darin

[johnmcdougall]

Thanks darinray, you are so right, if it was only so simple. I greased the grease points and the linkage seems to work fine. The external clutch spring (at the front of the floor plate) seems to act to help hold the pedal in or out as it goes over center, but I cannot see anything to help it past that center position. I may need to give up and rig an extra spring if I cannot solve it easily. As usual reluctant to change as it must actually work normally assuming that there is only 1 spring
John

[darinray]

Yeah... There is no grease fitting on the bearings I was talking about and that is why they seize up and don't allow the clutch to return to engaged position with that spring. All you have to do is undo the linkages, marking them before removing, and take the 2 bolts off the mounting bracket and pop those bearings out and replace or soak in penetrating liquid and that may free them up.

Darin

[Swamp rat]

On the problem with your shaft not stopping, pull the floor panel up and you can see you brake band on the shaft. On mine the nut had loosened up and wasnt pushing hard enough to engage the band. All it took was a couple turns with a 9/16 deep socket and readdy to co again.