I opened up my drum this past weekend to find grease all over. I assume the rear axle seals failed. My question is...can I get by simply replacing the seals or do I need to get new bearings? Seals would be $30 job v. $500 for paying to get new bearings, etc. pressed on.

 

It is possible your vent got plugged and forced the Gear oil out.

The only way you will know about the bearing is to see what it feels like when you pull it out.

Did you have any noise as this was happening ??

 

No road noise that I can tell. Do you mean a simple fix would be to clean the vent or should I still replace the seals?

 

A clogged vent will build pressure in the rear diff. Causing oil to push out into the drum. Clean the vent. Run or for a bit take the drum back off and check to for more grease. ( be sure to clean out that which is already in the drum)

Make sure no grease is on your brake shoes. It will ruin them.

 

As others suggested, you should look at/clean out the rear differential breather ('vent'). The issue with doing just the seals and not bearings is if the bearings are the root cause, your new seals are going to blow/leak again, and you are back doing the job again.

Do you not have the option of just paying for the bearings to be pressed off and replaced (And use OEM bearings if so)? That shouldn't be $500 (The whole job on the other hand might be $500), but I guess I don't know where you are from and what labor rates are and what kind of Toyota-based mechanics you have/etc. Most shops charge an arm and a leg for this service because they don't have a tool to press the bearings off, so you are paying them to basically rent one + their labor on top of that.

Have a look at below thread as well, he gives you a brief description on how to 'test' the bearings once the Axle's are out.

http://www.toyota-4runner.org/3rd-ge...d-3rd-gen.html

 

How many miles on the truck? I replaced my left rear bearing for the first time last week (at 303,000 miles) and will replace my right one today. This includes all seals as well.

If you are not even close to this kind of mileage, you're probably fine just replacing the seal. But it must be done correctly or the new one will fail in short order.



Andreas

 

Yes, that thread is where I got the $500 figure to do both sides having someone press them on. And later in the thread, it mentions even new bearings will have some play so I don't know if I can use his method to test the old ones. Seems you need a SST to do it.

223,000 miles. Only the right (that I can tell) is leaking.

On a related note, I did change the differential oil @ 197k and used Mobil 1. I wonder if changing over to synthetic at such high mileage contributed to the failure.

 

Grease is already on the shoes. I haven't changed them yet as I wanted to fix this leak first.

I guess I'll just clean the vent for now, clean up the drum, top off the diff oil and run for 1,000 miles and check for more grease.

 

Doubtful. I change the oil in both diffs and the transfer case every 50,000 miles and have always used Mobil1 75W/90. Purchased the truck new.



Andreas

 

One thing to watch out for is that the gear oil from the axle can wash the grease out of the wheel bearings. So when you fix the root cause (bad seal or plugged diff breather), and clean up the mess (brakleen on the drums, possibly new shoes) and everything is back to normal, no leaks, the wheel nearing might be on track for a premature failure due to lack of grease. The oil that washed the grease out won't stick around for long.

 

This was the first time it was changed it. Bought @163k and from what I can tell was running dino since new. Changed to synthetic @197k. I wouldn't suspect this to be a contributing factor if it was running synthetic from the beginning like yours.

I'm afraid this is true, but it's a risk I'm willing to take. Too many other projects around the house to worry about.