Hot wheel signals problem
By Brad Bergholdt
Published: Saturday, Jan. 12, 2013, 12:01 a.m.
Q I've got a 2005 Town & Country minivan. While we were out viewing some holiday displays, I noticed the right front wheel got very hot — so hot I couldn't touch the wheel. It smelled of burning, similar to electrical smoldering. The left front was warm, but not hot. We had been driving around only for about an hour, but there were some hills involved. I had the brake pads and rotors replaced less than a month ago. The van didn't pull to the right or feel like there was a brake issue. I had the mechanics (at least three) examine the brakes, and they could not find any evidence of overheating. The caliper was working freely. So, no parts were replaced after the incident.
What else could cause this? They said they checked the wheel bearings. This is front-wheel drive. I specifically asked whether they would let their mother drive it, and they said yes, it was safe. Should I be concerned or get another opinion? My brother, a retired mechanic, says there is still something wrong. It just means we haven't found it yet. How would you handle this?
AIt sure sounds as though the right front brake caliper piston failed to properly retract or binding of the caliper's sliding pins caused continuing clamping of the brake pads. A faulty wheel bearing can generate considerable heat but would have additional identifiable symptoms such as looseness and/or noise. Good job identifying the excessive heat was localized to one wheel, as that rules out a multitude of other possibilities.
Your Town & Country van employs disc brakes on the front axle. Single piston calipers squeeze brake pads against the brake rotors as hydraulic pressure is applied by the master cylinder. When pressure is released, a square-cut seal surrounding the caliper piston twists back to its relaxed position, drawing the piston ever so slightly rearward. This action, along with a slight amount of knockback from rotor run-out, allows required brake pad/rotor clearance. The brake caliper floats on pins, allowing the caliper's single-side clamping force to be equalized to both sides of the rotor and relax to an unloaded position.
Your comment about the brakes being recently renewed means the caliper pistons now reside deeply within the caliper bore, in an area previously exposed to possible corrosion and gunk. Brake fluid attracts moisture, and without periodic replacement it's possible to encounter problems such as pitting of the caliper bore and/or sticky antilock brake solenoid valves. Contaminated brake fluid also is a possible culprit. Should a petroleum-based fluid be accidentally added to the fluid reservoir, swelling rubber seals can lead to a variety of problems. I also wonder if the caliper mounting pins and bores were cleaned and lubricated at the time of brake service. If not, it's possible for them to bind.
There's a reasonable chance this could occur again. After double checking the freedom of caliper movement, I'd consider renewing both front calipers, just to play it safe.
Brad Bergholdt is an automotive technology instructor at Evergreen Valley College in San Jose, Calif. Readers may email him at email@example.com; he cannot make personal replies.
Show commenting policy
TribLive commenting policy
You are solely responsible for your comments and by using TribLive.com you agree to our Terms of Service.
We moderate comments. Our goal is to provide substantive commentary for a general readership. By screening submissions, we provide a space where readers can share intelligent and informed commentary that enhances the quality of our news and information.
While most comments will be posted if they are on-topic and not abusive, moderating decisions are subjective. We will make them as carefully and consistently as we can. Because of the volume of reader comments, we cannot review individual moderation decisions with readers.
We value thoughtful comments representing a range of views that make their point quickly and politely. We make an effort to protect discussions from repeated comments either by the same reader or different readers.
We follow the same standards for taste as the daily newspaper. A few things we won't tolerate: personal attacks, obscenity, vulgarity, profanity (including expletives and letters followed by dashes), commercial promotion, impersonations, incoherence, proselytizing and SHOUTING. Don't include URLs to Web sites.
We do not edit comments. They are either approved or deleted. We reserve the right to edit a comment that is quoted or excerpted in an article. In this case, we may fix spelling and punctuation.
We welcome strong opinions and criticism of our work, but we don't want comments to become bogged down with discussions of our policies and we will moderate accordingly.
We appreciate it when readers and people quoted in articles or blog posts point out errors of fact or emphasis and will investigate all assertions. But these suggestions should be sent via e-mail. To avoid distracting other readers, we won't publish comments that suggest a correction. Instead, corrections will be made in a blog post or in an article.
- Minorities crucial to filling Marcellus shale gas drilling jobs
- JPMorgan whistle-blower gets $64M for mortgage fraud tips
- Samsung introduces free streaming radio service
- Employers nationwide added 175K jobs despite harsh weather
- Demand grows for digital deal suppliers
- Teach your engine well
- Coca-Cola CEO’s pay, bonus drop
- Car only as good as its tires
- Dick’s undercover rival, a Modell’s top executive, spurs lawsuit
- Cabbies protest ride startups
- Fraud charges stand for Facebook claimant