TMC's "Shop Talk" session sheds light on problems with wheel-end bearings, tires, and air starters

Shop Talk, a free and open discussion of what does - and sometimes doesn't - work in vehicle maintenance, has quickly established itself as one of the most popular and best attended sessions at meetings of The Maintenance Council of the American Trucking Assns.

And the Shop Talk session at TMC's recent Summer Meeting in Milwaukee was no exception. What follows here is an attempt to bring you not only the questions asked and the answers or suggestions offered but also some of the flavor of the interchanges. For example:

Q. Has anyone else experienced a problem with failure of trailer wheel-end bearings - both inner and outer bearings - that have been packed with synthetic lubricants?

A. More likely than not, the problem is related to bearing installation.

A. We've noted some problems. We believe they are the result of moisture getting into the grease.

A. Lube manufacturers do not recommend #00 synthetic lube for non-drive axles. Today's better wheel can retain transmission lubricant, which is what they recommend.

A. There are reports - unconfirmed - that some trailer builders will not pack with synthetic grease.

Q. On new vehicles going into service, do you switch front tires - right-to-left, left-to-right - at about 60,000 miles to equalize wear?

A. We find the left front tire wears two to three 32nds faster than the right, so switching really pays off.

A. Many loggers switch at 30,000 to 35,000 miles and find that it works for them.

Q. How many fleets here are outsourcing their maintenance? Is anyone bringing it back in?

A. We outsource tire, engine, and transmission work, but we do all our own preventive maintenance (PM).

A. We don't get the quality from outside service suppliers that we can get in-house.

A. We outsource everything. We check the first few PMs very closely and critique them. We establish the PM program and provide the vendor with PM forms. So far, we've only changed vendors once.

Q. Has anyone experienced problems with air starters, especially in northern climates?

A. Our air starters work fine, but you must spec very carefully (air tank size, etc.) and keep the air system tight.

A. They have proven very effective in our predominantly stop-and-go service. We've had some problems with moisture in the air, but that's not a starter problem.

A. Air starters can be a penalty and cost you dollars at trade-in time.

A. We [a large, nationwide over-the-road carrier] have been on air starters forever, and we've never encountered a trade-in penalty.

A. Electric starters are more popular because people are more familiar with them and they can be replaced almost anywhere.

A. The weight savings projected for air starter use (two batteries vs. four, for example) often are outweighed by the extra weight of the required air system and tank.

Q. Is there an increase in the use of power inverters to run in-cab appliances? Is this a problem?

A. Team drivers will usually add appliances, so if you don't provide an inverter, they'll get one at a truckstop or somewhere else. You can provide a good one ($1,000 or so) or they can pick one up for $75 or $80. There are inverters and there are inverters.

Q. Is the use of super-single tires on the rise?

A. This market is flat. They're not moving into the general freight carrier market, but they remain popular for specialty applications such as woodchip haulers and oil tankers.

A. We [a tanker fleet] use super-singles on both tractors and trailers, and we get 80,000 to 90,000 miles on the tractor tires before we switch them to the trailer position.

Q. How can we reduce air-conditioning maintenance work?

A. Replace the receiver/dryer every time you crack (open) the A/C system, and convert from R12 to R134a when you do it. Otherwise, there is no need to replace a functioning receiver/dryer.