ShadowsPapa
Well-Known Member
- First Name
- Bill
- Joined
- Oct 12, 2019
- Threads
- 178
- Messages
- 29,084
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- 34,569
- Location
- Runnells, Iowa
- Vehicle(s)
- '22 JTO, '23 JLU, '82 SX4, '73 P. Cardin Javelin
- Occupation
- Retired auto mechanic, frmr gov't ntwrk security admin
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- 3
LOL OMG - you even doubt your doctor.So you are saying machines are always right? Or every single assembly that moves down the line gets the same amount? They don't run any other axles on that line? "X" amount couldn't be off by a little bit more than what the book says? Weren't there some assemblies with no lube sent out? Or was that the driveshaft support bearing with no grease? A lot of what about this or what about that. I understand you have a mechanical background but you aren't the only one that knows automobiles and what you say isn't the say all be all. You weren't there on the line when these assemblies were built so you really can't say it wasn't overfilled. It could be multiple of issues that lined up for the perfect storm. Who knows and again I'm sure we'll never know the true answer.
Yeah, in this case I'd say I am right.
You aren't getting the logic - or LACK OF related to the "over-fill" talkers.
Mechanical background? Well beyond that. (I've taught this stuff)
So you and no one else has explained how being over-full will cause a leak - explain how. Show me how it would happen. Why would oil on the back side of a seal cause a leak - explain in detail. You can't.
You can't even explain why the RIGHT seal and not the left - why not the pinion seal? IF it's over-full causing this - why not the left axle? I'm waiting........ explain why being over-filled will only leak out the right side.
I can explain how it wouldn't cause a leak.
You have no logic at all - just don't like my explanation. You want a simple answer - you want to blame someone.
It doesn't matter if they are a bit over full. Seals are made to run IN oil with oil behind them. In fact if there wasn't any oil, they'd burn up.
If people think there's too much, like I say, pull the freaking plug and look! If it doesn't run out, it's not too full. Even if it does it won't matter.
There, that's simple! If you have an axle seal leaking simply pull the plug, if nothing comes out it's not over-full! Gee, wasn't that easy??
That means it won't leak any more, RIGHT?
If the "it's over-full, that's the reason" people are correct then if you have a leaking axle seal, pull the fill plug, and if lube runs out, let it - put the plug back in and you've just fixed it because gpwrang says that's a cause of these leaks.
Seals are made/designed to run with oil fully behind them - clear up to the top.
The bottom seal on your lawn mower engine is a great example - running 4,000 RPM with oil sitting on top of it - a quart of oil laying on top of that seal. So how could a differential being over-full cause a leak? Explain it - instead of arguing against me by saying "because I said so and you aren't necessarily right".
They are made to hold up to 7 psi back - in most cases, some even more, but a typical single lip seal can handle some pressure.
In fact, some pressure SEALS THEM tighter.
These are typical seals like used in axles. The red arrows on the right part of the image represent any pressure that may exist. Any pressure in the housing presses EQUALLY in ALL DIRECTIONS. That's a law, a rule - I didn't make it up, it's the science of pressure, hydraulics, etc. Any pressure in that housing presses equally in ALL directions. INCLUDING on the lips of the seal.
That means the pressure actually holds the seal lip tighter against the axle. So a certain amount of pressure is not a negative thing. Too much is because it causes WEAR, friction.
Gee, look at this, a text book drawing showing OIL against the back of an AXLE SEAL. Amazing, so is this over-full too? This book MUST BE WRONG because we know any lube in that tube will cause leaks.
I have other BOOKS that explain this as well - from FORD, GM and others. So I guess if I'm crazy so are Ford and GM engineers?
OIL against the back of the SEAL - normal, not too full. This is what seals do.
Here is one with a bit of preload using what they call a garter spring. Yes, that's the name. It keeps the seal lip tight in cases of NO PRESSURE, as in front wheel bearings of a car but is also used in engine seals where there's light weight oil, etc. It's just a different design.
Here's another one I modified to show how any pressure (within reason) PUSHES the lip of the seal tighter on the shaft to seal even better. Pressure is equal in all directions meaning it pushes the lip against the shaft.
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