Wheel hub ass'y replaced, but a question.

[DonS47]

Had this annoying hum in the left rear wheel. Concluded, with help from a friend, that it had to be the wheel bearings.

When I went to buy a set of bearings, I found out there is a one-piece hub assembly - $46. (It's been awhile since I've done my own auto repair.)

Replaced the left rear wheel hub assembly.

I'd say it's a 45 minute job, but it took me close to four hours, since I broke off one of the two mounting bolts that hold the torque plate to the rear axle carrier.

Managed to drill that out and retap, but it took forever and another trip to the store for bolts, screw extractor (didn't work), and tap.

One thing I think I may have messed up is the geared wheel for the ABS. The one on the old hub had white grease on it, so I lubed it with lithium grease.

The more I think about it, the lube on the old one was probably from the blown bearing seal in the hub.

I don't think it presents a danger, but it may reduce the effectiveness of the ABS.

Any thoughts on this?

(Oh, and the hum is gone! )

[toyomoho]

Is this the ABS encoder ring?

[DonS47]

Okay, I'm guessing your trying to tell me something.

Sometime last night, it occurred to me that the plastic thing in the real axle carrier was the sensor that counted the rate of spin of the toothed wheel that I was worried about. That means the white lube wouldn't have an adverse effect on the ABS.

Okay - when all else fails, read the manual...

Haynes, Chap 9, "The rear wheel sensors are bolted to the axle carrier. The sensor rings are integral with the rear hub assemblies."

Decoder ring?

[toyomoho]

Never having seen this particular cars ABS sensor setup I cannot say for sure. It sounds like the ABS encoder. The manual fails to show this setup. The ABS system would have an encoder ring with notches, marks, etc around the circumference. There is a stationary ABS pickup sensor that picks up these marks, notches as they pass by. The sensor sends an electrical pulse to the ABS computer. One pulse per mark, notch, etc.

Find the stationary sensor, and determine what moving part on the axle lines up with it.

I am guessing the axle hub is a sealed bearing and has an O-ring that fits between the hub and backing plate. On cars with rear drum brakes, high temp white grease might be used on the parking brake adjustment mechanism.

Can’t say what effect greasing the rotating encoder will have on ABS performance. If you did grease the sensor, try to clean off it off. Make sure that grease did not fly off the encoder and onto the stationary pickup sensor. This might affect ABS performance.

[DonS47]

The Haynes manual calls for an o-ring, but I did not find an o-ring on removal of the old hub ass'y, and the new hub ass'y didn't come with one, so I installed the new hub ass'y without an o-ring.

I'll get an o-ring, pull the wheel and hub again, clean the encoder wheel, and reassemble, with the o-ring.

Thanks for the feedback!

[toyomoho]

Sounds good!

The O-ring must be there to keep water out of the bearing.