Bobcat 873 turbo- Hudraulics

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rootsman

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Jul 16, 2007
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Thanks Fishfiles your response was the most logical.After draining the chain case 3 times, 40 gallons of hydraulic fluid is a bit much to keep draining.Is there a way to check to see if seals are bad either way i will be draining chain case in the morning. Thanks again.
 

Tazza

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If you are draining that much fluid you definitely have bad seals on the drive motors. Its better that the oil leaks from the cover as it will damage axle seals if the pressure is allowed to build up.
 

Fishfiles

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Feb 8, 2007
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I reseal both drive motors when there is leakage into the chain case , it takes about 2 hours for each side , there is a procedure to isolate which one is leaking , but I have forgot how it's done , I would guess you could remove the hoses from one side and cap the fittings , with the machine jacked up , oil level correct and the plug out , you should be able to run the one side still hooked up and see the oil level come up , reverse the procedure for the other side , by the time you do all that , reseal both sides and your sure and finished ,
 

skidboy

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Jan 3, 2007
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94
I reseal both drive motors when there is leakage into the chain case , it takes about 2 hours for each side , there is a procedure to isolate which one is leaking , but I have forgot how it's done , I would guess you could remove the hoses from one side and cap the fittings , with the machine jacked up , oil level correct and the plug out , you should be able to run the one side still hooked up and see the oil level come up , reverse the procedure for the other side , by the time you do all that , reseal both sides and your sure and finished ,
I think you should be looking at the motor carrier seals.You have to remove the drive motors to access them.They are the only seals that stop hydrostat oil getting into the chaincase.
 

rootsman

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Jul 16, 2007
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I think you should be looking at the motor carrier seals.You have to remove the drive motors to access them.They are the only seals that stop hydrostat oil getting into the chaincase.
Thanks again, you guys have been very helpful.I had to order 2 seal kits this morning not knowing what seals need to be replaced.I also hope that the motor carrier seals are included in the kit because these kits aren't cheap.Each kit cost $270.00x2. I will update you guys on my progress later in the day if the seals arrive overnight as promised by the dealer. Thanks for your contributions.
 

skidboy

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Jan 3, 2007
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94
Thanks again, you guys have been very helpful.I had to order 2 seal kits this morning not knowing what seals need to be replaced.I also hope that the motor carrier seals are included in the kit because these kits aren't cheap.Each kit cost $270.00x2. I will update you guys on my progress later in the day if the seals arrive overnight as promised by the dealer. Thanks for your contributions.
Unfortunately the seals are not included in the motor kits.I would be returning the seal kits as that is not your problem.
 

Fishfiles

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Feb 8, 2007
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sorry i should have said drive motor kits
I have changed the seal kit of many travel motors and not the carrier seals and stopped the flow of oil into the chain case , I have changed the carrier seal but only when I could see the spring or lip deformed or damaged , the 873 has two different set ups depending on serial number , one model has 1 carrier seal and 1 has 2 carrier seals , the set up with two is a lot harder to do than the 1 seal set up , the most important seal in the kit that you will need is the white plastic concaved seal that seals the end of the output shaft on the motor side
 

skidboy

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Jan 3, 2007
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94
I have changed the seal kit of many travel motors and not the carrier seals and stopped the flow of oil into the chain case , I have changed the carrier seal but only when I could see the spring or lip deformed or damaged , the 873 has two different set ups depending on serial number , one model has 1 carrier seal and 1 has 2 carrier seals , the set up with two is a lot harder to do than the 1 seal set up , the most important seal in the kit that you will need is the white plastic concaved seal that seals the end of the output shaft on the motor side
I thought that all 873 s had Rexroth motors and they dont have that seal ?
 

rootsman

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Joined
Jul 16, 2007
Messages
11
I have changed the seal kit of many travel motors and not the carrier seals and stopped the flow of oil into the chain case , I have changed the carrier seal but only when I could see the spring or lip deformed or damaged , the 873 has two different set ups depending on serial number , one model has 1 carrier seal and 1 has 2 carrier seals , the set up with two is a lot harder to do than the 1 seal set up , the most important seal in the kit that you will need is the white plastic concaved seal that seals the end of the output shaft on the motor side
My motor has 2 carrier seals and were very difficult. I have changed both sides, the left side once and the right side 2 times, my chain case is still leaking. I am almost positive that the right side is my problem,I will be taking the right side apart to figure out why i keep blowing seals.If any one needs to kwow anything in this area i will be glad to help in assembly or disassembly.
 

Tazza

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My motor has 2 carrier seals and were very difficult. I have changed both sides, the left side once and the right side 2 times, my chain case is still leaking. I am almost positive that the right side is my problem,I will be taking the right side apart to figure out why i keep blowing seals.If any one needs to kwow anything in this area i will be glad to help in assembly or disassembly.
Do you have case drain filters on your motors? if so, they may be blocked causing excessive pressure that will easily blow the seals out.
Just a thought....
 
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