maintenance question

[tecciball]

my pathy is going in for annual inspection this weekend, and i was gonna have my mechanic also flush some of my fluids - oil, lsd, tcase. i am a few k from the 60k interval, but i doubt they have ever been done.

 

after reading another post here (sorry for jacking that one), i am thinking i should add wheel bearing repacking to my list of maintenance items. do both the front and back need done, or just the front? from the install process i have read about on bearing repacking, it would make sense to upgrade to warm hubs at the same time, since the labor would likely already be paid for. is this assumption correct?

 

thanks again for your help.

[Simon]

Just the front. The rear is not supposed to be serviced. It's rare that they go anyways. Not unheard of, but rare.

[tecciball]

is the bearing repack a periodic maintenance item, or an as needed item?

[mws]

How long do you want them to last?

 

The engineers want them serviced regularly.

The marketers want to claim they never need service.

The "business managers" just want them to last until the warranty expires.

 

Properly cared for, they could easily last a million miles.

[Trainman]

 

Properly cared for, they could easily last a million miles.

 

Thats the key, what is properly cared for?

[herm]

1997 w/115,000 miles. Original wheel bearings, never serviced, seem to work fine. The fronts are a PITA to get to, so I figured I'll wait until they actually go bad, and then drop in a new set.

 

m.

[88pathoffroad]

Properly, they should probably have the grease changed every 30K or so, I believe. Usually they never do, but if you REALLY want to get all precise about it...there you go.

[mws]

How to properly care for bearings? When properly designed, manufactured, and lubricated, ball/roller bearings have a near infinite life. What kills them is water (corrosion), dirt (abrasion), and mechanical failure or fatigue (poorly manufactured or loads in excess of designed parameters).

 

The key is to repack whenever the grease gets contaminated (dirt or water) or the grease begins to break down or separate. So the answer on how often to repack is truly:

 

IT DEPENDS! (sorry)

 

If you're using a premium synthetic grease in quality bearings in a pathy used exclusively on road and never has the hubs submerged in water, servicing every 100K miles would be plenty. Even 200K may be fine.

 

If you use el cheapo generic wheel bearing grease in generic chinese bearings from discount auto parts and do a lot of off road driving and routinely drive in 18" or deeper water, you may need to do it as often as every 5K miles to prevent excessive wear and detect material failures.

 

 

As a side note, many road cars today come with factory sealed and un-serviceable cartridge bearings. These come packed with premium grease and are sealed extremely well - so these can go 500K miles (or more) in a typical road car environment.