Bobcat 7753 hydraulic oil suddenly low?

[jrbean1]

I read the other post to this problem of the 7753 hydraulic oil suddenly low. I would get a leak of hydraulic fluid under the machine. The machine would be parked on stone and never put a drip pan under it. It would be about 1 or 1 1/2 gallons low. The machine would sit for about 2 or 3 months sometimes longer. Other times in the winter I would use it more to push snow around. . Open the chain case plug and there is all the hyd. fluid. I just of had about 10 gallons in there before it stopped coming out the plug hole. Right now is were the level should be. This leaking went on for about 1 or 2 years. I was just thinking it would leak because I was not using it enough. The other post leans to the Drive motor and/or carrier seals leaking. The motors that are between the wheels show no signs of leaking on the out side of the motor. Is there any special tools that I am going to need to replace the seals beside a slide hammer?? I work on cars trucks and motorcycles and do the regular maintance on the bobcat so I think I could handle this. Is there any tips you guys could offer to me to make this job easyer. thanks for any help.

 

[nshoregrappler]

I removed my drive motors from my 763 to have the motor seals replaced, and while the motors were out I removed and replaced the carrier seals. I used a slide hammer with a screw fitted to the end of the hammer, (drilled small hole careful not to damage inner parts) had the new carrier seals prior to removing the old seals. Having the new seals allowed me to see where the safest place to drill and pull out the old seals. I used a piece of schedule 40 pvc pipe 4 in (if i remember correctly) measure against the new seal. I then used a piece of 2x6 across the pvc and gently drove the new seal in place. this is not a big deal and easily done. Have plenty of clean rags to be sure not to allow materials to enter the system that might damage the new seals. Power wash pump area before starting the job, made for a cleaner work area. I did remove the tires to make access easier and supported the axles on jack stands. You will need to reseal the drive motors as they have to be the source of the hydraulic fluid or oil in the drive system. the oil is probably leaking out of the drive motor seal around the "drive shaft" of the motor and the hydraulic motor operation is building pressure against the carrier seal forcing oil into the chain case. The job should only take a few hours including removing and replacing the tires, I waited till the drive motors had been resealed, and I had the carrier seals in hand to do the entire job at one time. I labeled all the hoses as to their position on the drive motor and the motors labeled (marked) as to left or right side, just in case. I had drained the hydraulic reservoir and changed or cleaned all the hydraulic filters. I recommend you do the same keep it clean and avoid damage to the new seals. Expect 4 hours of work but days of waiting on the reseal of the drive motors, unless you do it yourself. I chickened out of doing the reseal job myself, only because I was new to bobcats at the time. Now my attitude is "it's already broken, what's the worst I could do now?") good luck.

 

[SSdoxie]

Leaking carrier seal does not always mean the drive motors are leaking internally and need resealing. By design, case drain oil from the motor flows into this area between motor and carrier to lubricate the splined drive. The most common cause of these seals failing is plugged case drain filters. There is a metal canister filter on the case drain hose going from motor back to reservoir. These filters should always be replaced if a carrier seal has started leaking oil into chain case.

 

[jrbean1]

Leaking carrier seal does not always mean the drive motors are leaking internally and need resealing. By design, case drain oil from the motor flows into this area between motor and carrier to lubricate the splined drive. The most common cause of these seals failing is plugged case drain filters. There is a metal canister filter on the case drain hose going from motor back to reservoir. These filters should always be replaced if a carrier seal has started leaking oil into chain case.

Thanks for all the info. Now I just need to make time and do the job. We'll let u all know how I make out.

 

[dirt ditch]

Leaking carrier seal does not always mean the drive motors are leaking internally and need resealing. By design, case drain oil from the motor flows into this area between motor and carrier to lubricate the splined drive. The most common cause of these seals failing is plugged case drain filters. There is a metal canister filter on the case drain hose going from motor back to reservoir. These filters should always be replaced if a carrier seal has started leaking oil into chain case.

Thank you for the information. My 7753 has been seeping oil around the right drive motor cover. Last time I used the machine the BOSS computer started beeping a HP-2 warning. The posted warning list under the display says it is a plugged return filter as you mention. My fluid loss has just started being noticeable and no oil on the floor when parked. I'll start with replacing the filter and see what happens.

 

[dirt ditch]

Had a local equipment mechanic replace both case drain filters. They definitely needed changed. He did not think I had any major issues after inspecting the machine. The mechanic also suggested that I run it for a while and keep an eye on the fluid level. If it does loose fluid we can then check the seals. Just picked up the machine and took it to the car wash for a good cleaning. Only a few minutes of running but no more HP-2 warning from the BOSS computer.

 

[jrbean1]

Well I completed the job and no leaks. This forum is a great tool. Thanks again