PDA

View Full Version : Repairing a dozer flywheel



coalsmok
10-28-2013, 08:54 PM
I do a lot of reading here but little posting, but here is a little project I just finished.

We are preparing a site for a new house and one neighbor offered to loan us a dozer and the other would operate it. I just have to pay for repairs and fuel. Well two hours into the access road the main clutch gave out.

This is what was found to be the cause
http://i369.photobucket.com/albums/oo138/coalsmok/shop%20projects/5f61548eeae54d3e137bf0fe8e3ea9dd.jpg

Centering it up
http://i369.photobucket.com/albums/oo138/coalsmok/shop%20projects/f5f64ce07c66451fb0af89fd085ac491.jpg

Pilot bearing hole cleaned up and repair sleeve before install
http://i369.photobucket.com/albums/oo138/coalsmok/shop%20projects/a76896d8a2e4065d61f3734978d5762e.jpg

Finished
http://i369.photobucket.com/albums/oo138/coalsmok/shop%20projects/2c6e9893ec2b23f4cd0be6ac4a30d61d.jpg

kf2qd
10-28-2013, 09:03 PM
AHHHH - you learned the magic of bulldozers. They are the most awesome toys - IF someone else is paying for the repairs. They spend all their life trying to tear themselves apart. They are one constant repair... Enjoy.

Don Young
10-28-2013, 10:05 PM
Good job on that repair! Hope you caught it before any other damage was done.

flutedchamber
10-28-2013, 10:53 PM
Excellent. One question tho...what is that bead of weld from that is adjacent to the hole? An old repair perhaps?

Lu47Dan
10-29-2013, 12:35 AM
I did a Minneapolis - Moline 870? flywheel this summer, bored it out and sleeved it then sent it out to be ground, when it came back I installed the bearing and took it back to the customer. I installed the sleeve with Cat bearing and sleeve retainer. He said the tractor is working fine.
He spent about $2000 on the flywheel repair, the surfacing, new clutch plate(s) and pressure plate, bearing and a new input shaft and bearings. Plus a bunch of other parts he needed.
Nice work.
Dan.

coalsmok
10-29-2013, 05:39 AM
The. owner has been having trouble with input shaft bearings and seals ever since getting this dozer but never pulled the clutch till it quit working. The weld is from where someone has previously tried welding the bearing or a shim in? Made it hard on tooling to bore the hole out. I ruined two carbide endmills trying and stopped when I got it mostly round. There was enough wall thickness on the repair sleeve to allow me to true it up on the mill after installing it.

flutedchamber
10-29-2013, 10:16 AM
That's what I assumed. It's a shame there are people that think that they can weld, and a welder and a cutting torch is a cure all.

epanzella
10-29-2013, 10:40 AM
That appears to be the pilot shaft bearing. With the transmission input shaft flopping in the breeze at the front end, the input shaft bearing is likely toast as well. Also mike up the front of the input shaft where it enters the bearing you're replacing. It may be worn undersized or eccentric. It's magic moments like these that caused me to get rid of my dozer and just rent whatever I need. If you think a breakdown sux in your driveway, you would really hate a breakdown on a remote jobsite in the woods with snow on the ground. A mechanical issue can turn a useful machine into a 10 ton roadblock in 2 seconds flat. Good luck.

A.K. Boomer
10-29-2013, 11:08 AM
ditto what Epanzella just wrote and in fact was going to be my comment but I will add the following,

your front main is most likely toast, that is most likely a given due to the amount of slop the other bearings bore went through,

now you have a situation, you've taken all the slop out of the shaft but not with the massive front main but a small little nosecone pilot bearing that's also way far away from the mains loading area - it is in no way/shape or form designed for this, you stand a very good chance at snapping the nose cone off the mainshaft if you assemble "as is" ,

I can't imagine all the work you had to do to get this far just for two hours of use of their POS,,, don't get screwed even further - tell them what the score is and let them know you need "real money" for all the work your about to do on top of the barter you got going on ------- one should not have to rebuild an entire dozer drivetrain for a little bit of work... good luck - but please heed my warning - not a good situation to just throw it back together...

Edit; you are in deep - real deep - it's tranny rebuild time... I can guarantee you that once you go in to replace that main you will find so much more as everything has been running in the old mains hash, you can count on pretty much replacing every bearing in the trans if you want to do it right,,, im sorry but really time to have a sit down talk with the owners - in the meanwhile take a measurement of the mainshaft slop and let us know how much...

if it's really excessive you may have some damaged gear teeth... :(

Abner
10-29-2013, 12:08 PM
After tearing into my old cat I can attest to what the others are saying. I had a leaky seal on a final drive. Bull gear was loose and wore out the splines on the shaft. By the time I was done I replaced every bearing, shaft and gear in that side. There are many problems not address by a simple repair to that bearing housing.
This is not fair to you and I think they should pony up or you should return it in "like it was" condition. You can easily dump thousands into a machine worth less than the repairs, I know this from experience. I would get away from this thing ASAP, and expect them to hate you as the worst possible outcome.

PStechPaul
10-29-2013, 12:09 PM
I bought an old IH TD340 dozer in 1987 for about $3100. It ran pretty well and the tracks were in good shape, but the rollers and idler wheels were about worn out, and the brakes/clutches were very marginal. It would have cost about $2500 to get it fixed, and I had already done most of the work I needed to do. I sold it around 1995 for about $1500. It was fun to drive but I found that it is much better to just rent one or even hire someone with a dozer. I had a guy spend a full day roughing in a 300 ft driveway and it cost only about $400. Here's my "big cat":

http://pauleschoen.com/pix/BIGCAT.JPG

jkilroy
10-29-2013, 12:52 PM
"They spend all their life trying to tear themselves apart."

Yes, in that way, Bulldozers are the helicopters of the ground. A large powered oil leak.

krutch
10-29-2013, 01:26 PM
My dad was half owner in a dozer. He used it on his property for a couple of years with no issues. Other half took it to his property and broke it! Traded up (or actually down), broke that one and then consulted with my dad on getting a third machine. This other guy had worked at a pit mine where overworking a dozer had no meaning. When one broke there, they got the next one and kept working. Those dozers were D-7 or some such beasts and the machines he was breaking were smaller yet he worked 'em like big Cats. The last one he broke by filling with oil AFTER locking a main bearing cap on the crank shaft. I know because that is what I found when I opened it up to try to fix it.
Same guy went into custom corn picking. He'd buy a used combine and run it like a new one throwing chains and such then go buy another one to replace it. Ended up killing his wife's business with all the debt from his tearing up equipment.
While looking for a rental house for a friend, we saw a large anvil with the horn busted off. So I told this dozer killer we found his lost anvil. He was mad as hell but with all his wife's customers present, (they were laughing at my quip) he could only color up.

Willy
10-29-2013, 03:22 PM
ditto what Epanzella just wrote and in fact was going to be my comment but I will add the following,

I can't imagine all the work you had to do to get this far just for two hours of use of their POS,,, don't get screwed even further - tell them what the score is and let them know you need "real money" for all the work your about to do on top of the barter you got going on ------- one should not have to rebuild an entire dozer drivetrain for a little bit of work... good luck - but please heed my warning - not a good situation to just throw it back together...

Edit; you are in deep - real deep - it's tranny rebuild time... I can guarantee you that once you go in to replace that main you will find so much more as everything has been running in the old mains hash, you can count on pretty much replacing every bearing in the trans if you want to do it right,,, im sorry but really time to have a sit down talk with the owners - ... :(

My thoughts exactly and probably the main reason I've always lived by the old adage of...never a borrower or a lender be. I've always been better off in the long run renting or hiring.
As some of the others here have suggested, don't be talked into what you hoped would be saving money, by fixing someone else's broken down machinery.
Who knows how much time and abuse that old cat has already endured...and now it's your turn to spin the wheel and hope it doesn't fall apart while using it.
Tell the neighbor tactfully that time is more important at this point and that you'll hire someone to do the job, after all winter is coming and you can't afford to work on, and or repair equipment all winter.

You've got a new house to build. You probably don't have the time and money to rebuild a machine who's history you don't know.

mike4
10-29-2013, 08:03 PM
There is another way to look at this as well , he may have had enough sense to stop when it started to make strange noises , or was an operator not a seat warmer.
If its not your machine then dont make extra work for yourself either , just repair what is necessary to finish your job and hand it back with a warning that it could be needing more work soon.

I have seen people whose efforts on a dozer are nothing short of equipment vandalism , they charge into obstacles or expect a D4 to work like a D11.

Any equipment is designed to be used within its capabilities , unlike what a lot think "its a dozer you can trash it ", any machine will break if abused .
Michael

coalsmok
10-29-2013, 08:27 PM
Yep just repairing whats needed to get it thru this job. Its not a free rebuild for them. The operator is very talented and operates with the age/condition of the machine in mind. There was no funny noises from the clutch area it just stopped.
I have no intention of doing all the work with this dozer but at the moment the work needed is within how we normaly use it. Not certain what most of you picture when I say preparing a house site but right now there is nothing but walk in access and trees. I dont have a deadline to complete things just need a access road to get a farm tractor on site and some help with moving the timber as I fell the trees. Then I can move our portable band mill on site to turn the trees into lumber for a new shop, outbuildings and some of the flooring for the planned house. Once all that is completed then I will get the financing to build the house and contract out the excavating and pouring the foundations.
Right now though I have more time than money so am taking advantage of the fact that this dozer cost me nothing while it is just sitting on site waiting for me to have time or a need for it.

Willy
10-29-2013, 09:25 PM
Glad to see you're on top of it Coalsmok. I believe many of us here, probably including yourself, have been taken advantage of by "friends and neighbors" because of our mechanical or machining skills and equipment. I think some of us perceived that perhaps this may have been happening to you.
We just didn't want you to be taken advantage of.

As long as everyone at your end is on the same page, and it sounds as if they are, you'll be fine.
With any luck at all you wont be getting too much more, machining dozer parts "practice" until you are in your new shop.:)

A.K. Boomer
10-29-2013, 10:55 PM
Willy - tell him about the changes he made and how it could immediately disintegrate his mainshaft if he put's it back together with the fixed pilot bearing,,,
im R&Ding a buddys dope pipe and can't get into it right now. don't worry - legal in my state... :p

Willy
10-29-2013, 11:07 PM
Hey I agree about your prognosis about the main-shaft bearing, I'm sure he's read your reply and will act accordingly. I don't think he's prepared to rebuild buddy's cat, parts and labor included just to put in an access road.
Legal or not, you shouldn't smoke that stuff, it's bad for your health. Use a vaporizer, that way you're not inhaling all that burnt stuff.http://i76.photobucket.com/albums/j31/250willy/cee48e43.jpg

Paul Alciatore
10-30-2013, 09:48 PM
I can't believe that big flywheel runs on that tiny bearing. No wonder it broke.

Or is it just me that thinks this?

Willy
10-30-2013, 10:50 PM
I can't believe that big flywheel runs on that tiny bearing. No wonder it broke.

Or is it just me that thinks this?

It's a pilot bearing. One end of the transmission main input shaft is supported and stabilized by this bearing in order to keep it centered to the axis of rotation. The other end of the transmission's main input shaft is supported by a much larger bearing in the front of the transmission's case.
The flywheel is just a carrier for the bearing that the small end of the input shaft fits into.

Paul Alciatore
10-31-2013, 12:31 AM
So the bearing at the other end holds up the flywheel? ..... ??? I need an explanation as to how that works. I mean, I could understand if there were bigger bearings on BOTH sides of the flywheel, but if the flywheel is at one end of the shaft and the big bearing is at the other end, then I fail to see how that bigger bearing offers much support for the flywheel. Others here have suggested that dozers are maintenance heavy. There must be reasons for that and this sure looks like a possible one.



It's a pilot bearing. One end of the transmission main input shaft is supported and stabilized by this bearing in order to keep it centered to the axis of rotation. The other end of the transmission's main input shaft is supported by a much larger bearing in the front of the transmission's case.
The flywheel is just a carrier for the bearing that the small end of the input shaft fits into.

camdigger
10-31-2013, 01:41 AM
I can't believe that big flywheel runs on that tiny bearing. No wonder it broke.

Or is it just me that thinks this?

Hmmm, I always thought the flywheel was supported by the end of the crankshaft with it's multiple journal bearings. The bearing replaced by the OP looks like the outboard bearing of the transmission input shaft usually called the pilot bearing. The function of the pilot bearing is to keep the transmission input shaft aligned when the clutch is disengaged and the tranny shaft is turning (or not) while the flywheel turns with the engine crank.

mike4
10-31-2013, 04:51 AM
+1 on camdiggers reply , it looks like a previous repairer??? had tried to weld the bearing in place .
Michael

coalsmok
10-31-2013, 06:09 AM
Well i sent the flywheel to the owner to install with the message to check the input shaft bearings. Was told he had replaced it with the seals in the not so distant past, he thought that was the cause of the seal failure.
Willy yes I have been taken advantage of in the past to fix/repair things. I am just paying for parts or making small repairs like this one as needed. The owner takes care of having the work done, I have no desire to learn dozer mechanics, engines,farm equipment and guns is enough to keep me too busy.

Yes someone in the past tried to weld something in there.

Willy
10-31-2013, 08:36 AM
Paul I'm sorry but a good teacher I'm not, I tend to make too many assumptions.
But we have visual aids at our disposal so this will help us illustrate the point somewhat better.
As Camdigger explained, the flywheel is bolted onto the engine's crankshaft, who's bearings support it. If you look at the photos of the flywheel that Coalsmok provided you will see a series of holes around the pilot bearing, these serve to mount the flywheel to the engine's crankshaft. A clutch bell housing is bolted directly onto the back of the engine. This housing serves to not only contain the clutch, but also acts as an interface between the engine and transmission.

The illustration below is a greatly simplified one, fundamentally showing 3 different styles of pilot bearings, keep in mind it does not show the clutch bell housing that surrounds the clutch and joins the engine and transmission. It does however show the relationship of the pilot bearing to the transmission input shaft. Remember this shaft sticks out well past the transmission, goes through and is splined to the clutch, and is then supported and kept in axial alignment to the engine's crankshaft by the pilot bearing centered in the engine's flywheel.

http://www.freeasestudyguides.com/graphics/pilot-bearing.gif

A.K. Boomer
10-31-2013, 09:32 AM
Coalsmok that's good to know - then it's on him,
Me and Willy were just looking out for you as we thought you were taking it in the shorts and doing all the work,

Willy - stop whooping up on yourself, your one of the best teachers on this site, and as someone else stated a class act - who else goes through the trouble to post a diagram of where a pilot bearings located,,, Just to clarify to CS the pilot bearing can be stuffed into the end of the crank like above or designed into the flywheel - basically the same difference as far as function although when replacing the crank style can be a PITA to get out due to it being a dead end and needing a slide hammer or puller to remove whilst the flywheel type can be pressed or driven out when the flywheels removed...

there are also pilot-less designs but these have to have trannies that have the mainshaft firmly supported in order to do this.

I always wondered what a Dozer flywheel looked like and thought it would have some mass to it, there's a little kinetic energy storage for ya...


Nice repair job...