ZTR wheel motor leak. How do the bolts seal

[LD1]

Dads mower has a leaky wheel motor. Pretty sure its leaking between the sections. Each section is sealed with a square profile o-ring....and seal kits are avaliable.

But when taking it apart and looking at it...we are pondering what keeps oil from leaking around the bolt heads?
If you have ever taken apart a wheel motor.....the long bolts that hold all the motor sections together are INSIDE the o-rings/seals. Thus the thru bolts are exposed to the oil. But what actually keeps oil from seeping out around the bolt head. There are no o-rings or crush washers on the bolt heads.

 

[LD1]

Probably not the exact motor, but similar. You can see the bolts go through inside the seals. So what keeps oil from weeping out around the bolt heads???

 

[seville009]

No idea, but if you can find an exploding parts diagram online, that may give you an answer.

Is it used? If so, maybe the prior owner did some work on it and did not replace the seals/gaskets (if they exist). Just a wild guess......


Edit: you beat me to it....

 

[LD1]

No idea, but if you can find an exploding parts diagram online, that may give you an answer.

Is it used? If so, maybe the prior owner did some work on it and did not replace the seals/gaskets (if they exist). Just a wild guess......


Edit: you beat me to it....

It was a new mower 15-20 years ago when dad bought it. Replaced the hydro pumps last year because one took a crap.

A wheel motor is dripping now. Pretty straight forward to put a seal kit on it.

Just looking at the design though.....has us pondering how the bolt heads actually seal. I have taken apart several wheel motors before....and there is never any type of seal that seals the bolt head.

It obviously works, and doesnt leak around the bolt heads. Just wondering why is all? Is there really enough local pressure and/or metal deformation to create a high pressure seal under the bolt head?

 

[seville009]

Maybe just the tightness of the bolts effectively seals them. I thought when I initially read your post that oil was leaking through the bolts.

 

[BeezFun]

I don't think there is any fluid pressure in the area where the bolts are. Each of the plates (commutator, etc) has a machined finish that seals the high pressure. Seal #3 in your diagram is the low pressure seal against fluid getting into the area where the bolts are. Seal #4 I think is only to prevent water and contamination from reaching the spaces between the plates. I looked at some different motors on youtube, some are like yours with the bolts "internal" and some have them external. I think your setup is better because the bolts are protected against the environment so you won't be fighting with rusted bolts to get them out.