Just wondering: what causes leaks?

[HoosierJeeper]

Random thought of that day...take pinion seals or transfer case seals or oil seals. What conditions make them leak, or is it all random (barring damaging during a repair etc)? I.E. is it all age or all mileage? Does city driving cause more leaks where things don't get up to temp? Or highway trips? Or am I just talking nonsense and trying to waste bandwidth? LOL

 

[BalticBob]

all of the above.......plus manufacturing defects and quality control at the factory or repair shop.

 

[HoosierJeeper]

So basically...if it's gonna leak it'll leak no matter how you treat it?

 

[dishdude]

Originally Posted By: HoosierJeeper

So basically...if it's gonna leak it'll leak no matter how you treat it?

I would agree with that. I think age is going to be the biggest contributing factor.

 

[Merkava_4]

Leaks are caused by seals that are either shrinking, losing their pliability, or not bonding to their mating surfaces. The words 'pliability' and 'conformability' can be interchanged when it comes to seals and gaskets.

 

[SubieRubyRoo]

Pinion/transfer case, the round seals... almost always have some kind of damage to them. Rocks flying up, suffering bad vibration from a shot u-joint, damaged during installation... Gaskets, if they are the o-ring style are almost always damage or poor installation. Cork gaskets are shrinkage. If you keep clean, healthy fluids in each piece of machinery and prevent physical damage, nearly every seal or gasket will live a long, happy life.

 

[jeepman3071]

Originally Posted By: Merkava_4

Leaks are caused by seals that are either shrinking, losing their pliability, or not bonding to their mating surfaces. The words 'pliability' and 'conformability' can be interchanged when it comes to seals and gaskets.

This. I think a lot of it has to do with heat cycles, and how resistant the gasket material is to those cycles.

 

[Langanobob]

A lot of the seals I’ve changed have been high mileage and completely worn out, some with the spring riding directly on the shaft and damaging it. Some seal leaks are due to loose bearings that allow too much shaft motion, that seems to sometimes be the case with pinion and axle bearings. Sometimes a plugged housing vent will cause a pressure buildup that pushes fluid past the seal. Only know of one seal that leaked due to a manufacturing defect. About city driving vs highway, just a guess but I’d say that the total number of shaft revolutions is a big part of the leak equation, so highway driving wears seals faster. But no facts to back that up.