Tire Troubles
Q I just tore the sidewall in my new $300 tire. Is there any way this can be repaired?
A Pretty much any tire shop can repair a puncture in a tire's tread. Whether by simply adding a plug or by dismounting the tire and vulcanizing a patch on the inside, it's safe to drive a tire repaired in this manner on the street.
However, a tire's sidewall is composed of fewer, thinner plies of laminate material. While adding plugs and even sewing a sidewall up with wire to get yourself off the trail is acceptable, it's simply not safe to drive a tire with puncture damage in the sidewall on the street. And since most tire warranties and road hazard programs don't cover sidewall damage past the tread blocks, it's a safe bet you'll be buying a replacement tire.
Whirling Dervish
Q I want to lift my XYZ Jeep XYZ inches. Will I need to install a CV rear driveshaft?
A This is one of those questions that can depend on a case-by-case basis, but there are some general rules of thumb. Remember, vehicles with longer factory rear driveshafts can get away with more lift before a double cardan (commonly referred to as a CV) shaft is needed. Assuming the drivetrain is left in the stock position, meaning the engine is not raised and the transfer case is not dropped, here are some general rules of thumb governing at which lift heights a double cardan rear driveshaft becomes a necessity.
JK - Over 3 inches (2 door); Over 4 inches (4 door)Wrangler - Over 3 inches (TJ/YJ); Over 4.5 inches (Wrangler Unlimited TJ)XJ - Over 3.5 inchesFlattie/CJ-5 - Over 2.5 inchesCJ-7 - Over 3 inchesFSJ Wagoneer/Cherokee - Over 6 inchesFSJ Pickup - Over 8 inches
Rust Bust
Q I've been trying to get the stub shafts out of my Dana 30's unit bearing with no luck. What's the trick?
A Even down here in the southwest were it never snows and hardly ever rains, separating the stub shaft from a Dana 30 unit bearing can be a chore. The problem lays in the fact that in order to prevent vibration, the shaft's splines engage into the unit bearing with a rather tight press fit. Throw in years of rust and corrosion and you'd better be prepared for a fight when trying to dismantle some of these assemblies.
Your best method will involve a lot of time, patience, and penetrating lube. There are a lot of good ones out there, but you'll have to get a bit more serious than WD-40. I've had excellent results using Justice Brothers JB-80 (justicebrothers.com) and Federal Process Corporation's Free All (federalprocess.com).
Soak the nut and the shaft splines before starting. You may need to go as long as a week, reapplying the lube once or twice per day. If the nut hasn't rusted away, an impact gun will be your best bet for freeing the nut. Otherwise, go for a long breaker bar and give it hell. If the edges of the nut have rusted away, you could try a pair of channel locks or even Vise Grip pliers, but I wouldn't hold out much hope for either working.
Once you get the nut off, either use an air hammer with a blunt bit to free the stub shaft from the unit bearing or thread the shaft nut back on a few turns to protect the stub shaft threads and whack away with a heavy dead blow hammer. Resist the urge to use a steel sledge, as it will likely result in serious shaft or bearing damage. And don't break out the torch. Aside from the fact all that penetrating lube will go up like a Roman candle, you'll probably waste the bearing's seals.