Posted by Clint Dixon [172.71.254.30] on Thursday, January 12, 2023 at 10:15:35 :
In Reply to: front brake contaminant posted by Jerry Henry [172.71.146.248] on Wednesday, January 11, 2023 at 23:40:12 :
Once the dust from the wearing brake shoes, along with atmospheric dust, gets mixed in with whatever brake fluid and/or gear lube is in and around the brake drum and hub, it all looks, feels, and smells like that.
I agree with Tom on how to check for leaking brake cylinder.
A quick and easy check for a leaking oil seal within the axle shaft is to look at where the truck is parked for extended periods of time. Does a spot or small puddle of fluid collect on the ground just inside that tire? If so, you probably have a leaking seal within the axle housing. The wipers on the steering knuckles were designed to retain grease, not a grease and gear lube mix, so any gear lube that finds its way to the knuckle is going to leak out eventually.
A little bit more involved way to check for a leaking axle housing seal is to remove your locking hub. If a dark mix of grease and oil in the consistency of pancake syrup)or thinner) leaks out, you have a bad axle seal and the grease within the steering knuckle has been contaminated and thinned by the lube.
If it has gotten to this point, your wheel bearing grease is probably thinned with gear lube also. Not that that necessarily hurts the bearings, but it will eventually leak past the hub seal next to the brake backing plate. Which is what that drain hole is really designed for that was mentioned below.
Junior