Saturday is Car Project Day

So I find myself with that rarest of things: a summer Saturday with nothing scheduled *and* decent weather. Miss E had to work the breakfast buffet at the hotel where she started earlier this week, and K had a volunteer shift at the local DV shelter, so I had the place to myself (well, myself and Scooterbird). And I had things to do to Leviathan: try to fix the parking brake, and solve the leak in the rear axle cover. To that end, I purchased a front parking brake cable (which is what had failed the last time and it sounded like it had failed again this time) and, to replace the replacement stamped-steel rear axle cover (the original rusted through in about 3 years and 85,000 miles, this one has about 120,000 miles on it), a nifty die-cast-aluminum cover with cooling fins that Ford has made available on the 2008 model year F-Series Super Duty pickups.

(There’s an aftermarket aluminum cover available as well, but it runs about $250, and this one is $50. Guess which one I bought?)

Anyway, I needed RTV form-a-gasket, brake clean (great degreaser), a drain pan that would capture the old lube and allow me to transport it to the oil change place for proper disposal, and 4 quarts of synthetic 75W-140 gear lube. $85 and change later, I had the stuff. Yep, $85: $4 RTV, $3.20 brake clean, $9 drain pan, and the synth gear lube runs $15.99 per quart. Ow. On the other hand, the stuff works great, and when I cracked the cover loose on the diff, what came out was in very good shape for being 5 years old with 120K miles on it.

By the way, gear lube? Don’t get it on anything clothing items you like. Particularly used gear lube. The smell is less with the synthetic than with the traditional dino juice (and in really old days, legend has it sperm whale oil was a component), but it’s… bad.

So, spray the rear axle with Simple Green to first knock loose as much of the accumulated cruft as possible, then tackle the parking brake cable.

Sigh. I’ll skip to the end: it’s not the cable. But to determine that, I had to disconnect the batteries (yep, plural: most diesels have two in parallel), which involved some effort on one of the ground terminals, then work my arm down into the back of the engine compartment and undo the 104-pin connector for the transmission computer (which is attached with a 10mm captive bolt), which ended up also requiring the loosening of the fenderwell splash shield so I could retrieve the ratchet wrench I dropped. Once that’s done, you can then crawl under the dash and remove a nut and a bolt to remove the trans computer… and THEN you can see the parking brake pedal mechanism…. at which point I learned that the cable was, in fact, intact. Something else is broken, probably the pedal itself. And I don’t have one of those. So I’ll have to try that again later.

Put it all back together up front and started in on the rear end. It’s pretty straightforward: remove twelve screws, pry off old cover. There’s a neat trick I learned years ago: leave one screw at the top of the cover in place but loose, so when you pry it loose, it won’t come crashing down on top of you in a shower of used gear lube. Instead, when you pry it loose, the gear lube hits the shallow drain portion of your storage-style drain pan and slops up over the side, getting your gravel & dirt driveway all oily. And that smell…. ooh, that smell. It also runs down your arms and while you were smart and are wearing surgical gloves instead of your preferred (but not oil-resistant) Mechanix Wear work gloves, your forearms are now seriously slimed.

Did I mention that you’re under a truck, lying on your back or side, and if you jump when this happens to grab from your Box O Rags (disposable paper ones, not your good red shop rags. See above on gear oil smell and cloth), you hit your head on an assortment of metal objects with varying degrees of rust and an array of edges, sharp pokey things, etc.? Well, I didn’t jump, at least.

Anyway, old cover off, let the axle drain, then start cleaning up the sealing surface with a razor blade and the brake cleaner. Clean the new cover with the brake cleaner as well, let it dry, and then apply a bead of RTV to new cover. Now the really tricky part: get yourself and the now-gooped cover from tailgate to under the truck without bumping it against anything or dropping it on the dirt & gravel driveway. To my utter and complete amazement, I did it on the first attempt. I even remembered to put the bolts down there (in a nifty magnetic parts tray so they weren’t in the dirt, either) first. Cover onto the rear end, get the 12 bolts started while holding it, tighten a couple down to secure the cover, then finish tightening them.

Then take some time to clean things up a bit, because you want to let the RTV set up a bit before you subject it to the new gear oil. Which mean that almost an hour later, I was ready to put the oil in. Which is done via a small plugged hole on the side of the differential housing. You remove the plug, and start putting the oil in. When you have enough oil in, it’ll run out the plug hole. Sounds simple, doesn’t it? Well, you can’t get all the oil out of the jug unless you attach a piece of rubber hose to the nozzle on the oil jug so you can tip the jug upside down. At which time the hose slips off the nozzle, comes out of the plug hole in the axle, or both, and you have another mess on your hands. And arms. Took a while, but got the required 3.3 L of oil in there. I wasn’t measuring, I just filled it ’til it ran of the fill hole. 🙂

This is where the aftermarket cover has one advantage: there’s a dipstick whose hole is on top of the cover, so you can tip the oil jug completely upside down into it without the hose. Their dipstick is marked funny, though, so you’re best off removing the regular fill plug to serve as your level indicator, then mark the dipstick with the actual correct level. But I don’t have one of those, so I did it the regular (messy) way.

But… no drips, no leaks, and it looks cool, too.

I wound up shoveling up the oil-soaked soil and gravel and disposing of it… Finished up everything including the test drive around 12:45 — after both Miss E and K had returned home.

Tomorrow, if I have time, I may swap out my front side windows for the thicker ones a friend of mine got for me — thicker glass means less noise into the cabin from outside.


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