John Deere 490 travel motor brake seals

[Johndeerekid]

My machine is filling the left final drive with hydraulic oil. It drives totally fine so I am suspecting that it’s the brake seals/orings. From the John Deere break down it looks the main orings I need are part #TH100494 but they are not available. Any help finding the seals is much appreciated the old machine doesn’t want to give up and be a shame a couple orings takes it down

 

[Deere500a]

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

 

[Deere500a]

490 was abandoned 20yrs ago by Deere parts are rare.Mcmaster has lot of aftermarket o'rings.Not mine just pic.

 

[Johndeerekid]

That definitely looks promising, does anyone happen to know the dimensions
Of the seals before I tear it apart? I always rather have the parts before hand but if I have to I will take it apart and measure them up

 

[Diesel Dave]

Welcome to HEF Johndeerekid .
See 2 screenshots below. The propel motor mounting oring and brake piston seal kit is # AT130924 . The kit subs to 3 part #’s shown in second screenshot. I believe all the o-ring part #’s are available.
***Edit , you also need o-ring #17 in parts list , part # CH17167 ***



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[Tones]

I don't think your problem is with the break. A worn motor increases the casedrain pressure and pops the output shaft seal which then fills the planetary drive.
I recommend further investigation like a casedrain flow test before pulling it apart or you'll be fixing what ain't broke.

 

[Johndeerekid]

If you look at the break down I just don’t understand how the shaft seal can leak around the brake housing. It looks like if the shaft seal was to leak it could only leak into the brake housing and then only fill the final drive if the brake housing is leaking

 

[Johndeerekid]

The machine also drive no problem like it doesn’t lack any power on that track and if the seal was gone and lots of case pressure wouldn’t it be noticeable loss of drive power?

 

[Tones]

Not necessarily, considering the age of the machine both motors could be worn,one more than the other.
Thats why testing is cheaper than guessing. At the end of the day it's your machine and dough and I'm only passing on what I learnt the hard way.

 

[Johndeerekid]

I definitely don’t want to guess but if you look at the break down I don’t even think what your saying is possible.

 

[Johndeerekid]

It just seems like the brake piston would block oil from the shaft seal, so if the case drain pressure was high it wouldn’t matter if the brake seals were fine and the brake pressure is higher then the case drain