So, my rear wheel bearing seal was leaking gear oil into the parking brake for a few weeks now, enough to smell after a long drive with lots of braking. I first saw it was weeping a few months back when I did the rear brakes.

Replaced the seal, everything went smoothly. Found the right tool for the wheel bearing nut for $18.91 on Amazon: Amazon.com: Powerbuilt 648476 Spindle Nut Socket Special: Home Improvement

For the record, it's a Powerbuilt 648476 Spindle Nut Socket. It fit my 2001 SRW F250 Sterling 10.5" - Also got the Motorcraft BRS-116 wheel seal from Amazon for $27.07

Salvaged the parking brake shoes by using plenty of CRC Brake cleaner. Since they aren't used as real brakes, just for parking, I figured any degradation of the linings from the solvent wouldn't be an issue.

Buttoned everything up, had a few beers and went to sleep. Woke up the next day ready to do the rear brakes in my wife's Cougar. Took them apart, found the piston boots were on their way out, and worse when tightening up the caliper cup (rear disc brakes needed to be compressed by screwing in the cup), actually tore the boot. Which is good, because I actually found brake fluid leaking past the piston seal. So, off the Advance Auto Parts about 25 minutes away, to get the only pair of calipers I could find on a Sunday afternoon.

On my way back with the Superduty, doing about 70MPH on a three-lane highway, all of a sudden I hear a POP and the most horrendous vibration I've ever felt in a vehicle (well, except for that time I hit 135MPH in my '96-tbird and balloned the driveshaft, but hey, let's call it the worst I've ever felt under "normal" circumstances).

The vibration was so bad I couldn't see out all three mirrors, everything in the truck shaking. Sounded like a u-joint cracked, pinion bearing spun, or possibly that wheel bearing I had apart shredded itself.

Pulled over to the shoulder, just past the rise of a bridge, got out and checked underneath. The only thing I could see easy was the rubber cover for the driveshaft splines looked like it had exploded, so I'm figuring the slip joint had failed in some way.

Great, now I have to remove the driveshaft, and drive home in front-wheel drive. No tools on me, so I need a ride home and back. Call my brother-in-law who happened to be 10 minutes away. While waiting, I figured there was no way I could work on it on the shoulder of a major highway, so limped it off the highway into a parking lot.

Took another look, couldn't figure out exactly what happened. Jacked up one wheel, start checking for slap or resistance anywhere, couldn't find anything.

Finally, I got up close to the driveshaft slipjoint and couldn't really see anything wrong, nor why the rubber cover looked like it exploded. PTFE grease was everywhere...

All of a sudden I realized, the rubber piece hanging off was just long enough that, under centrifugal force, it would flex outward and slap the plastic shield above the catalytic converter!

5 seconds with a scissor from a multi-purpose tool I keep on my key-ring, and it was solved.

Sheesh. Shear panic, wife's car is on blocks, no vehicles left, thinking the absolute worse (or best, as if it was the rear, I was re-gearing to 4.30's )

Anyone know where to get the rubber spline cover?

 

And I even read the part about the wife's Cougar.

I don't know where to find that part, but glad it was such an easy fix. Funny that piece of rubber can cause the whole truck to shake.

 

its actually pretty thick if you look at it, best bet is a junk yard my friend, or a driveshaft shop?

 

Retired a few years back with intentions of doing a lot of traveling in my 5er and '05 F250. We sold our home and moved to our cottage in Canada for the summer months and intended to travel all fall and winter. We still spend the winters in the 5er (cottage isn't setup for year round use) but now we tend to park it for extended stays and make a lot fewer side trips. Made it to Corpus Christi for last winter but the return trip was $1500 in gas alone!

I can't complain though, we have a better life than most and feel very fortunate to still have our health and ability to travel. This is a great country!!