BACKYARD MECHANIC: Paint can prevent sticking alloy wheels

Hey there, time traveller!
This article was published 25/11/2011 (5391 days ago), so information in it may no longer be current.

QUESTION: I have a 2005 Toyota Matrix with alloy rims that had been installed by a Toyota dealer in May. In October, one of my tires went completely flat caused by a nail through the tread. I jacked up the car and took off all of the wheel nuts with no problems. The wheel was still stuck in place and nothing that I could do was able to shift it. I tried kicking the rim and levering on the rim up to the point where I thought the rim might be damaged, with no success.

The tire was too soft to give a firm surface that could be used for leverage, so I tried pumping up the tire with my hand tire pump but the air leaked out as fast as I pumped it in.

I called a CAA service technician and he was able to get the wheel off by pumping up the tire with his compressor and then hitting the tire with a big hammer. He said that the problem was caused by an electro-chemical reaction between the alloy wheel and the steel axle.

What could I have done differently to get that wheel off, and how can this kind of problem be prevented? Peter

ANSWER: The stuck wheel is caused by corrosion between the two dissimilar metals of the steel axle hub and the alloy wheel. Some can be extremely difficult to remove. One method is to loosen all the lug nuts two turns, drive the car about five feet forward and stop quickly. A couple of these manoeuvres usually cause the wheel to break free of the hub.

In worst-case situations, I have also had to weave the car back and forth — do this carefully, as you don’t want to damage a wheel.

To prevent this from happening next time, clean the mating surfaces of the wheel and axle and apply a coating of paint. This will act as an insulator between the two parts so corrosion is minimized.

QUESTION: I have a 2004 GMC Sierra. If I don’t use the truck for a few weeks, the battery goes dead. I have replaced the battery so it is in good condition. I have tried to determine what is causing the battery drain. I hooked up a multimeter and there was a constant draw of .05 amps (10 amp scale). I removed the fuses one at a time and found that when I removed the IGN A fuse (Ignition Power) from the underhood block, the amp reading dropped to .01. I think the problem lies somewhere there.

Can you please tell me what may be causing the draw in the IGN circuit and what tests I can do to further narrow down the problem? Thanks in advance, Florian

ANSWER: The IGN A fuse feeds the ignition switch and the starter relay power circuit. For there to be an electrical drain on this fuse, either the ignition switch would have to be staying on or the starter relay engaged, which would cause the starter to run. Therefore, there must be something else in between the IGN A fuse and the ignition switch that is causing the drain.

First, look for an aftermarket accessory. A remote starter module may be causing the draw. An aftermarket immobilizer system would be another likely culprit. Possibly someone has wired in a trailer brake controller to the wrong circuits. I suspect you will find that someone has installed something beneath the dash on the driver’s side that is causing this problem.

Most vehicles should have an electrical drain of seven to 12 milliamps and the maximum drain for your vehicle should be about 30 milliamps. If your vehicle has the maximum drain, the battery charge will only last about 23 days.

When testing for an electrical drain, it can take a couple hours before all the modules shut down electrically and the drain goes to the 7-12 milliamp range. If it is still high, you may have a faulty module on the truck that is not “going to sleep”. This is best diagnosed with a scan tool, which can monitor the module sleep modes to pinpoint a problem.

Even if the drain is in the 7-12 milliamp range, if you are going to park the vehicle for several weeks, you should either disconnect the battery or install a battery tender that will keep the battery fully charged.

Jim Kerr is an experienced mechanic, instructor and member of the Automobile Journalists’ Association of Canada.