OP
SOS
Silver Member
My dad bought it new about 2 years ago and has about 100 hours on it. And its only the right steering clutch that when bad -- my mistake.
30hp Chinese Bulldozer Parts
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Eagleview
Veteran Member
I wonder what could go wrong with a steering clutch at 100 hours ? I was talking to a chap a month ago , he had a brand new one delivered to his house . They unloaded it off the trailer , turned it around to put it in the shed and as it was turning , it spread its legs and broke the final drive housing in half . He swapped it for a used Komatsu D20 they had on the lot as he wouldn't accept another of the same brand .
Bob Rooks
Elite Member
Somebody did something wrong. Period. In all my years around crawlers I've never heard of that happening, except one time a 7A-D8 went head over heels into a 300' ravine. I think it's probably still there (operator jumped).
Too bad the D20's don't have TPH's and PTO's, otherwise nice little machines with powershift. But they are not without their woes too.
Bob Rooks
Elite Member
A lot, if it wasn't adjusted properly.
The foot pedal is supposed to be adjusted so that it compresses (collapses)the springs in the steering clutch before the brake is applied.
On the old Cats there were steering levers that you pulled by hand, and brake pedals that you pushed with your feet. Yuchai has combined both functions into the pedals, but nevertheless they are still dry clutches.
Eagleview
Veteran Member
I'll pass along what your reply was . Period .
Bob Rooks
Elite Member
LOL
Bob Rooks
Elite Member
The reason I said somebody did something wrong is that there is no mechanical connection between the swing (track) frames and the final drives. The swing frames are securely attached to each other (and the chassis) underneath the engine with a double trunion mounting which allows for running on uneven terrain and over obstacles. The sprocket is only attached to the tracks and is not machine load bearing, only the rollers are.
The scenario you described is highly unlikely, given human error.
Eagleview
Veteran Member
In my clouded mind , another thing he said came to me today . I remember he said it was a rubber track model . I'm wondering if the grip on the pavement he was screwing around on had anything to do with it . The dealer offered less than half of what he paid for it the day before , and he didn't want it fixed . That's why he swapped it for the Komatsu , he then advertised the Komatsu on Ebay , trying to recover some of his loss . That's how i came across him , i inquired about the Komatsu . Thinking about it now , maybe the sprocket tried to walk out of the track which would put a lot of strain on the housing .Bob Rooks
Elite Member
My dozer has rubber tracks too, and I have done pirouettes on asphalt and clean concrete with no damage except leaving a little rubber behind.
Something is fishy here.
He didn't want it fixed?
He wanted to sell the Komatsu too?
Has he had much experience around crawlers?
I have walked out of a track on two occasions, but I asked for it (and got it).
Lateral tractive forces are transferred from the track to the roller, to the swing frame, to the front equalizer bar (double trunion) and rear pivot rod, to the chassis (differential, transmission, and clutch housings). Nowhere does it transfer to the final drives. The only forces taken by the final drives are the torque and horsepower required to turn the sprocket, and the tensioning forces of the track adjusters. The sprockets and idlers don't even touch the ground and are not designed to be load bearing. Just like the big iron.
Oh well......
Something is fishy here.
He didn't want it fixed?
He wanted to sell the Komatsu too?
Has he had much experience around crawlers?
I have walked out of a track on two occasions, but I asked for it (and got it).
Lateral tractive forces are transferred from the track to the roller, to the swing frame, to the front equalizer bar (double trunion) and rear pivot rod, to the chassis (differential, transmission, and clutch housings). Nowhere does it transfer to the final drives. The only forces taken by the final drives are the torque and horsepower required to turn the sprocket, and the tensioning forces of the track adjusters. The sprockets and idlers don't even touch the ground and are not designed to be load bearing. Just like the big iron.
Oh well......
OP
SOS
Silver Member
Well gentlemen, I have a theory. My old dad has bad knees so him and another guy welded some hand steering bars on the control pedals and then adjusted the clutch or the brakes so they would work. Well in adjusting the clutch, I think they did not take into consideration the one or the other so it caused a lot of ware. In repairing the clutch, they took the makeshift hand controls off and readjusted everything.
