Another 4400 front axle leaking!

[The Haymaker]

As I read this from the outside and watch things swing back and forth, the first thing I notice is how many people feel they know more about oil selection than the manufacturer.

I keep things simple, I run what my books suggest I run.

Now I'm going outside to bleed off the axle on my tractor!

E

 

[Sam Marsh]

Every John Deere cut I've owned has leaked at the same place. They have a improved parts now I hear from my dealer. My 4520 has leaked 2 times since new there, and front pumpkin also. Waiting on improved parts to have dealer fix it. My friend has a 4720 with 800 hrs on it and oil is pouring out of the knuckle. Hopefully they have a fix this time. My service guy tlod me they don't tighten the holding nut tight enuff from the factory.I don't know it's a pain.

 

[defed]

after i got mine all cleaned up, taken apart and reassembled, i see how all the parts work together now. there is a sleeve over the shoulder and the knuckle seal rides on this. there is a small gap between flange on the sleeve and the rim of the seal where debris can fall into. there is no actual open space there, as the lip of the seal flares up to meet the sleeve flange. but it got me thinking....a boot over or even an o-ring in the groove might prevent dirt and such from getting in there and being ground into the seal while steering.

of course, a boot that size would be $100....i damaged my tie rod boot while removing, and JD wants $16 for it!?!?!?

 

[arrabil]

the first thing I notice is how many people feel they know more about oil selection than the manufacturer.

The manufacturer makes decisions that may or may not fit a particular person's situation. They may make decisions based solely on cost to them. And their own decisions may change as they receive repair feedback on the design. SO.... while I agree that I always use the fluid specified, I don't think there is anything wrong with changing it when you have the experience to know what the pros and cons are.

Heck, I just changed the pressurized axle to a vented one. I don't think I know better than Deere. I think I have the benefit of other people's experience to tell me I'd rather have less pressure on inherently weak seals.

 

[captin_insano]

. I think I have the benefit of other people's experience to tell me I'd rather have less pressure on inherently weak seals.

So your seals are ok for pressure a few posts ago but you decided they wernt ok for pressure? And in reguards to your confusiuon of pressure changes, air/oil/steel expands and contracts with every change in pressure...as you know. It doesnt take 100 degrees to make it change....:drool: Not every axle will make your woosh sound when you take out the plug, chances are if its leaking oil you know its leaking air too as it warms. Well the air will "leak" just the same back in when it cools and if its wet when it cools the water goes with it. The post with the milky oil is enough proof of that.

 

[arrabil]

So your seals are ok for pressure a few posts ago but you decided they wernt ok for pressure?

Er? My seals hold air and oil just fine and are designed to do just that. However I feel they will last longer not under pressure because of an inherently weak design.

air/oil/steel expands and contracts with every change in pressure...as you know. It doesnt take 100 degrees to make it change

No, but it takes 100 degrees difference in temperature between the inside and outside to make a strong enough pressure difference to make bypassing the seals possible (when they are in good working condition).

if its leaking oil you know its leaking air too as it warms

As I stated many posts ago, if this is happening your seals are shot. And if your seals are shot, pressure has almost nothing to do with why water gets in the axle. Its because the axle isn't SEALED anymore.

 

[dfkrug]

The manufacturer makes decisions that may or may not fit a particular person's situation. They may make decisions based solely on cost to them.

This is so so true. The manufacturing engineer has to choose processes
and materials that make the manufacturing process as fast and efficient
as possible, without unduly compromising durability. I can think of many
many cases where the factory choice is not the ideal one for an end user
who wants maximum long-term durability. It is not that I think I am smarter
than the tractor maker; I just have different priorities.

Perhaps low-vis hyd fluid is chosen by the factory for some front axles
because it can be filled quickly. I know that getting gear oil into some
axles takes a long time, esp when there is a fill hole on only one side.

When a factory chooses paper gaskets over silicone, assembly is faster, but
oil leaks after a few years are more likely.

When hardened pins are used in loaders, the pins and bushings wear more
evenly, allowing for more time before repair is necessary. I prefer a softer
pin so IT wears out before the bushing. I may have to replace the pin
sooner, but the much more difficult bushing repair is avoided. The maker
chooses the best compromise from his perspective.

Same with non-vented axles. The maker has made the judgment that adding
vents could invite more problems than the lack of vents would create.

Finally, if one sticks doggedly to the manufacturer's service specs for oil
changes, I know of at least one car company that says the tranny fluid is
"lifetime". No changes. What long-term owner is going to stick with that?