I have a older "about 1989" John Deere 70D excavator. Very similar to the hitachi EX60 except for the motor. I got it as a project (it will never do another honest days work again) and will probably need more than a few systems rebuild but I'm an engineer by trade and a major do-it-yourselver so I would like to repair it for kicks and giggles. I've researched this forum quite a bit and have found alot of useful information so I thought I would ask my own question. As far as I can tell, the hydraulic drive motors in most larger machines - say 10 ton or more are "axial" piston motors. The hydraulic drive motors on the 70D are "radial" piston motors. Why is there a difference? Is it due to the machine being fitted with a blade and would require more torque? The official John Deere site is great for yesterday's machines as they list all part schematics - but they have no technical info. Has anyone rebuild one of these "radial" piston motors - and other than the dealer is there any after market part sources? All ifo is appreciated
Joey from what i've heard the radials are cheaper and are not as stout as the axial motors. Its all based on load variances usually to which motor they will use. If you can get me some part #'s of what you need i will check and see what i can do for you..
Went to try and move the 70D into the garage to start my project but only one drive motor would work and it was turning in a circle. I couldn't use the bucket to help me get up the hill because I didn't want to tear my paved driveway up so I decided to tow it. I read somewhere you have to remove the planetary's to tow so this was what I started to do. All along I thought that my final drive didn't work because of either the rotary manifold or because the final drive motor was bad. When I removed the second planetary gear (I believe its the braking mechanism) I found the output shaft entirely eaten away from the sun gears. Notice in one of the pictures the roll pins all broken in the hubs of the gears. I believe this is what let the gears "fall down" on the output shaft and eat it away like a lathe!. Anyone had any luck welding and re-hobbing a shaft? My local John Deere supplier wants $1770 cdn for this shaft which is only about 1.5" in diameter by 6" long. View attachment both hubs.pdf View attachment hub removed.pdf View attachment 2nd palantary gear.pdf View attachment stripped spline.pdf View attachment excavator 1.pdf
better pictures of my failed final drive I've tried to post better pictures of my failed final drive. Has anyone had any luck in building up with weld then machining some of the worn/broken pieces themselves? If they have what hardness of material (type of rod) was used? my excavator project hub cover removed notice the sun gear looks quite good. Next picture shows the 2nd planetary removed - not so good!! stripped output shaft This is the reason my final drive failed, and this roughly 1.5" x 6" shaft is $1770 cdn + tax from the dealer!!! At first I thought either my rotary manifold or final drive motor was bad, but this was the ultimate culprit! 2nd planetary gear with gear removed - notice the location of the roll pins supposed to keep the hub and gear in place - all of them are broken! These gears seem to have fallen on the output shaft stripping it just like a lathe! hub and gear removed notice the wear on the hub from the gear In order to take the stripped output shaft out the drive, it has to be disassembled from the other side in order to remove the snap ring that holds it in place - If anyone is interested, I'll post pictures of that when I remove the drive completely and disassemble.
buddy I dont think you can fix it because you dont seem to be the sharpest tool in the shed. So, stop being so cheap and go to john deere and order one in !!!!!!!!!! You should be looking for corvette fenders!!!
bixby, I think we can do without comments like that.. Im not trying to be the police but give the man some credit for doing it himself. Then only way to learn is by doing it..
bixby went through the trouble to make an account just to post that. He must be a very grumpy person. I havent seen many of these machines, but you may be able to find used parts, the only problem with that is you could go to the yard pull it off take it apart and have the same problem, you just never know. If you want it done bad enough it can be done. And for those of us who have an abundance of time but not money doing it yourself is often the best solution.
Where u located in ga gatorguy?
Great first post Bixby! Welcome to the Forums....:cool2
Joey is right; you can't spend $1770 on a $5000 machine, especially if you don't have a revenue job needing it to go right back to work. So you gotta beat the bushes, try to find some used parts, or investigate if it can be re-machined. Seems to me that is what a sharp person would do, and this forum is a good place for that. A dumbass would just "order it in from JD".
I found this tread and do not mean to steal the tread, but does the owner of this 70D know where I can find the gears for the turntable planetary gears. I have a buddy that's looked everywhere for them. MY buddies is a 1970 model JD 70. He has two of them.
What to sell Joey, I was wondering if you were into selling your already started project? I'm looking for your exact machine. Let me know what you think. [email protected]