...can safely use brake cleaner to get it really cleaned up?
Or will the break cleaner do more damage to the seals?
The grease isnít really going to hurt anything down there, so I donít find brake cleaner necessary - I just wipe up the excess with a paper towel until itís clean. If you lubed properly youíre just going to have more grease flung around the U-joints anyway.
Now I want to do my 4Runner Trail what mileage do you start the relube maintenance?
I re-lube every time I do an oil change, so every 5,000 miles. As a matter of fact, I just changed oil and re-lubed the zerks today.
Now that Iíve done this a few times to my FJ, and can absolutely advise that pumping grease until you see it come out of the slip joints is the way to properly do this. The key here is that you HAVE to GO SLOW. By going slow, I mean pumping grease (slowly) until you see the drive shaft expand, and then STOP. Wait until the drive shaft settles to its original position, and give it another pump. Each time you pump, youíll see the drive shaft expand, but it will settle back to its original position. Keep doing this until you see grease seep out of the slip joint, and then youíre done.
Since I correctly lubed my slip joints last time, this time I got the same ďcracklingĒ sound from the slip joints that I get from the U-joints, which was soon followed by old moly grease. This means the seals are working properly and air is getting pushed out, along with old grease.
Again, if youíre not seeing any grease come out when you lube the slip joints, youíre not doing it right - but you HAVE to GO SLOW.