How often to replace bearing seal? Every 6M according to Dexter doc.

kailiu3000

I am following the Dexter maintenance schedule and inspecting my brakes (600-8k_complete_service_manual.pdf). According to the schedule, owners are expected to check the magnets every 6,000 miles or 6 months. In order to inspect the magnets, I need to remove the hub.  On page 58, there is a Note section stating "If hubs are removed from an axel with the E-Z Lube feature, it is imperative that the seals be replaced BEFORE bearing lubrication. Otherwise, the chance of grease getting on brake linings is greatly increased." 

Does that mean I need to replace the bearing seals every 6 month? Have you all following the instruction and replace the bearing seals every time the hub is removed? 

Thanks!

Kai

MuttonChops

Am afraid I don't  follow the Dexter 'inspection schedule'.

While I do replace the bearing grease (via the EZ-Lube) per Dexter's schedule I've not removed the drums for a brakes inspection over the past 32K miles.  As the trailer is doing great - - stops as it should.  Of course when dong the grease change - - -  I do check the backside to see if grease is leaking (seal broken).

I know the brakes work [ I can 'feel' the trailer braking while stopping] and I do adjust the TV Brake Controller 'power level' based on how heavily loaded the trailer is . . . plus my TV computer will tell me if can't "see the brake magnets".

I've assumed that 'maintenance schedules' are based on two factors:
1)  if the trailer axle is fully loaded . . . which most of our TaB's aren't
2) dealers like scheduled maintenance service income
      {even while they are so understaffed an appointment can be months away}

But even with the above I do change the grease, DIY, as suggested - - - it is easy and cheap - - -

When traveling I'll touch-test-the-brake-drum-temperature at Rest Stops . . . expecting them to be cool or warm but not hot or really cold . . .

Mickerly

I'm closer to MuttonChops. I've repacked enough wheel bearings on cars, this doesn't scare me. I'm very picky about the type of grease. Brakes are adjusted between every trip, approximately monthly. I check the temperatures at every stop. I remove the Echo brake controller before backing as a precaution. Annually, each winter, everything is completely disassembled, cleaned and reassembled. Once disassembled, a new seal is used during reassembly.

MuttonChops

Mickerly said:

I'm closer to MuttonChops. . . .

Brakes are adjusted between every trip, approximately monthly. I check the temperatures at every stop. . . .

Annually, each winter, everything is completely disassembled, cleaned and reassembled. Once disassembled, a new seal is used during reassembly.

LOL  

Sorry @Mickerly . . . . you are in a whole new world maintenance wise than I am . . .
All I've done over 32K miles and 3+ years is EZ-Lube the grease.

kailiu3000

What puzzles me is that If I don't disassemble the rear bearings, do I need to replace the bearing seal? It sounds like every time the hub is removed, the bearing seal needs to be replaced too. Have you removed the hub without replacing the seal?  Do you think keeping the existing bearing seal without unpacking will lead to grease leak?

manyman297

I personally wouldn’t worry about it. Just take care in removing and reinstalling your hub. 

The only time I replace seals are when I do an annual bearing repack. Mainly because I end up bending a seal when I remove them. 

6 months seems ridiculous to have to check anything on your brakes. Magnets do wear down but nowhere to the point of having to check them bi-annually. 

I check temps at random stops on trips.

tabiphile

@kailiu3000. Respect for following a recommended PM schedule. When we write these things, we would always hope someone will actually pay attention to them. That said, if you read Zen and the Art, you will see that sometimes the manuals are written by the least qualified. An outcome can be overly unnecessary maintenance requirements. It's a bit of CYA.
The magnets (and insides of the hubs) do collect dust. They do not require any more attention than the pads do. The time to clean these surfaces is when you do your annual brake and bearing service. There is zero need to pull the hub just to get at those magnets and insides of the hubs otherwise... when the time comes, pull the wheel, back off the brakes and pull the hub. Inspect it for wear, clean it meticulously with brake cleaner and then after you do your brake service, reinstall without getting any grease on them. 
Carefully pulling the hub does not require rear seal replacement...unless you can see that grease has found it's way in. Grease only can work it's way in if you blast it out by pumping too much grease into the bearings or if it wasn't properly seated to begin with. Seals are very cheap so mechanics will always replace them when they pack the bearings.
Don't be the guy who never pulls his hubs and never inspects the axles for wear. Except for this silly magnet cleaning thing, follow the recommended annual inspection and repacking instructions if you want to be confident that your wheel bearings and axles are not going to fail.

kailiu3000

tabiphile, thanks for your comments. That gives me some confidence in ignoring some of the documentations. The bearing seal should be robust enough to withstand traveling along the spindle couple times without breaking.

tabiphile

kailiu3000 said:

 The bearing seal should be robust enough to withstand traveling along the spindle couple times without breaking.

To be clear, that seal must be removed when you hand pack the bearings. It cannot be removed without being damaged.