BH90 Dipper Cyl

   / BH90 Dipper Cyl
  • Thread Starter
#11  
this one is 90 degrees ACC...
 

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   / BH90 Dipper Cyl
  • Thread Starter
#12  
heres the real problem...
 

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   / BH90 Dipper Cyl
  • Thread Starter
#13  
the black ring is a spacer that keeps the piston of the walls of the bore so this cylinder is designed to handle some side loading. The piston is not damaged. The seal is extruded. In the business this is refered to as seal extrusion. If the seal was not damaged during factory installation it is caused by pressure too high for the diametral clearance combined with heat which softens the seal.
I am just going to re-seal and see what happens.
I am also open to any ideas or inside information anyone may have, please speak up.
Thanks for looking,
Martin
 

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   / BH90 Dipper Cyl #14  
Ask Kubota for the parts to rebuild at no cost to you..... seems like the least that they can do for you. My opinion of Kubota is rapidly making a 180 degree turn for the worse. I keep seeing poor quality workmanship in what was once a good tractor brand.
 
   / BH90 Dipper Cyl
  • Thread Starter
#15  
Junkman,
the ball is rolling.
I have a message into Tom Sieper and will pursue it to the ends of the earth if they get me motivated.
I can be motivated by many things, answers that I know are bogus and ignoring me are only two.
My first priority is to regain use of the machine, I have an unfinished project to complete. I didn't want to buy anything until the cylinder was apart and was sure of the extent of repairs required. It looks like it just needs a piston seal. I was going to order the seal kits from Tractorsmart but they didn't have them on hand and to Fed-Ex from Columbus was an extra $40.- The dealer has them and the lovely missus will pick them up today. I should be digging tomorrow again.
I also opened the boom and bucket cylinder to avoid another early failure. The boom piston seal is perfect, the bucket piston has a small notch on one side lip which I can't believe should be there, so maybe this was on it's way out too, maybe not.
I will re-seal all three and pursue satisfaction with the manufacturer.
I will make an attempt to relieve the side loading to the best of my ability. The machine is at the site so I can't do anything to the hoe till I arrive with the cylinders.
Thanks for your suggestion, I will pursue it. An authorized credit at the dealer is as good as cash to me.
All the best,
Martin
 
   / BH90 Dipper Cyl
  • Thread Starter
#16  
Well we're back in business. The replacement piston block seal is a bugger to get onto the piston. I was hoping the piston was made in two pieces, split at the seal groove, but that is not the case. It is a bugger getting the new seal over the land and into the groove. I heated it up on a 60W light bulb to see if it became more pliable but the difference was imperceptable. I just used my fingers and persuaded it into place. It didn't tear but did stretch some so I fashioned a ring compressor from a strip of .008" spring steel and some hose clamps and kept things snug hoping it would return to the original diameter. Wha-Laa it worked slicker than a cats butt. The cylinder reassembly was a breeze. I had to take the hand grinder to the base of the dipper cylinder to relieve the side loading. I just ground a flat to the depth of the bushing and that was enough. Took about 1/4" off. It has reduced my opinion of Kubota to say the least. Because I know most of you can't read and only look at the pics (joking), here are a few...
 

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   / BH90 Dipper Cyl
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#17  
if you look at the profile in the bottom of the pic you can see how far the seal protrudes beyong the piston. There is a good lead-in angle in the cylinder bore but I was dead afraid the seal would shear...
 

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   / BH90 Dipper Cyl
  • Thread Starter
#18  
so I put together this mickey fickey ring compressor...
 

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   / BH90 Dipper Cyl
  • Thread Starter
#19  
an end view snap of the compressor...
 

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   / BH90 Dipper Cyl
  • Thread Starter
#20  
the three amigo's ready to go back to work...
 

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