Check your brakes
 

I thought my power-nothing 1989 Toyota Pickup did pretty well coasting, and I consistently returned 30-31mpg driving with moderate EOC in the city. I noticed that whenever I used and released the parking brake it took some time before the coasting ability returned. Turns out the lever in the driver's side rear drum was frozen, causing a shoe to drag all the time. Easy to fix, with DRAMATIC results.

I was at the end of my tank when I fixed the brake. Even so, I got a new high calculated tank mpg of 32. I am still on the first tank since the repair, and it looks to be the best ever mileage with the truck. I always note how many miles when the fuel gauge registers at the 1/2 tank mark, and it typically is between 200-230 miles. With no major changes to how I drive I passed the 1/2 way mark at 300 miles!!

This means I am on track to 40mpg on a tall 4wd pickup. I need to get a sticker to put on it saying "Got 40mpg?" :D

Good idea to check the drum temperatures, just put your hand on one then the other on the outside and see if one is much hotter.

Checked the mechanical brake adjustment on my 37 ford (all cables) with a laser thermometer, hotter, back it off cooler tighten it up. I could stop that car with my thumb.

regards
mech

Nice! Make sure to come back and update this thread when the tank result is in.

To that end...if there was a way to go 4 wheel drum brakes, that would return the best mpg. Disc brakes are going to drag...period. They relay on the elasticity of a square cut o-ring to open the brakes up when they are released. Keeping all the friction surfaces and the caliper pins cleaned and lubed would be a good preventive maintenance along with checking all the rear drum brake gear.

I'll concede that, all things being equal, disc brakes may have a touch more drag than drum brakes. And performing the maintenance items you mention is an excellent idea as well. But wheel bearings always have a bit of play and brake rotors always have a bit of runout, so brake pads are always going to be pushed back at least a bit from the rotor. Also considering the number and scale of other sources of friction in an automobile, disc brake drag is a pretty minor factor.

Drum brake drag from sticky cables however - I saw a *lot* of that in my mechanic days, and it can be considerable. Also folks should be aware that many cars with 4-wheel discs have separate drum brake assemblies, typically on the rear wheels, just for handbrake duties. Subarus for example have them inside the rear rotors. These tend to be ignored when servicing brakes and can be a source of drag just like a vehicle with rear drum brakes.

My Festiva coasted way better than my Insight does, and that car was about the least aerodynamic shape possible. That was because I bought an extra set of disc brake drag reduction clips and doubled up on them, so the disc brakes didn't drag at all on that car.

Really? I don't seem to have TOO much of a problem with THAT with my Mustang or my F-250. I've had MORE problems with eccentric drums.:p

Filled the tank today, entered it in the fuel log. Not as good as projected, but I got a solid 35mpg, 3mpg more than my best ever.

I added this fillup to fuelly.com. I have the highest fuel mileage of any Toyota pickup, including the 2 wheel drive versions, eheheh.

The rear calipers on my '06 Highlander Hybrid froze shut a couple years back. Fixing that got me 2-3MPG and much longer coasts.

Yes, I have to say with this brake repair and the manual transmission conversion on my VW, I have an entirely new outlook on how far cars can coast, and I am still recalibrating when to stop applying power.