Brakes are freezing on 1990 Dodge RAM diesel truck | Car Doctor

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Q: My daughter has a 1990 Dodge RAM diesel truck. She is having problems with the brakes freezing. She has taken it to three different places. They inspect the brakes and tell her they find nothing wrong.

She also has a problem with the brake pedal not fully returning, and at times she has to manually lift the pedal. Is there a problem specific to the truck?

A: Based on having to lift the brake pedal, I would replace the brake power booster and master cylinder. At 32 years old, the linkage from the pedal could be binding. When it comes to a safety item like brakes, you shouldn’t take any chances.

Q: I have a 2004 Toyota Tundra. For a few years now, the seat belt light keeps coming on (flashing) on the dash. I have taken the truck to three auto shops, including Toyota. They all told me that it could take weeks to figure out why the light comes on. None of them could offer an answer or a solution.

Toyota replaced the passenger air bag on a recall about a year ago and told me the seat belts are solid.

Can you offer any input on this ongoing problem? This is the only transportation I have, so can't leave it at an auto shop for weeks, and the flashing light just drives me nuts.

A: Inside the buckle are contacts that close when the seat belt is fastened.

Sometimes, I have seen that dirt, debris and even food in the buckle can interfere. If you take a thin cloth and soak it in alcohol and push it in the buckle, it should clean the contacts.

Other times, I have seen situations where the buckle needed to be replaced.

Q: I have a 2013 BMW 520d in India (I read your answers online), and it now has 50,000 kilometers on it. I have recently noticed that on a cold start every morning, it starts immediately, however, I notice a sputtering/rattling kind of noise in the engine that disappears once I drive it for 500 yards or so.

Any thoughts why I get this noise in the engine on a cold start?

A: If the engine is actually sputtering — running poorly — I would be looking at some type of fuel injector or sensor issue.

If it is just a noise, I would look at exhaust brackets. I don’t see many diesel BMWs, but a common problem on the gasoline models is a bracket near the transmission that breaks and rattles.

Q: I have a 2005 Chevy van, and the timing does not advance on my scanner when I accelerate. It has the V8 engine, which otherwise runs fine. Also, it does have a "check engine" light on for a random misfire code.

A: In the old days, I would say the ignition timing bypass connection is disconnected or broken. With your V8 engine using coil-on-plug ignition, timing adjustment isn’t possible, since it is fully controlled by the engine’s computer system. The ignition timing is based on engine load, temperature, speed, MAP and the input from the crankshaft sensor and knock sensor. The misfire of the engine is limiting timing advance and should be repaired first.

Q: I own a 2014 C300 4Matic Mercedes Benz. The mileage is 40,000, as I only drove 12 miles round trip to work. I had a 40,000-mile tuneup four months ago.

The other day, when accelerating from a traffic light, the car was hesitating — slightly chugging, I would say.

During this time, the engine light came on, and I pulled into a parking lot and ended up calling AAA and had the car towed to my trusted mechanic. He looked at the car the next morning, hooked it up to his diagnostic system and said no code was displayed and the engine light was no longer on. He drove the car and said it was fine.

I didn't feel comfortable taking the car home and asked what he would do if it was his car. He said it was probably an engine misfire and he would replace a coil. I told him to do that, and he ordered the part. Is this enough information for your educated guess on this issue?

A: Certainly, asking the mechanic what he would do if it were his car was a great idea.

There are any number of reasons why an engine can misfire and turn a check-engine light on. Replacing the ignition coil is certainly a good place to start, as the light coming on and the hesitation are characteristics of a faulty ignition coil.

AAA's Car Doctor, John Paul
AAA's Car Doctor, John Paul

John Paul is the AAA Northeast Car Doctor. He has more than 40 years of experience in the automobile industry and is an ASE-Certified Master Technician. Write to John Paul, The Car Doctor, at 110 Royal Little Drive, Providence, RI 02904. Or email and put “Car Doctor” in the subject field. Follow him on Twitter @johnfpaul or on Facebook.

This article originally appeared on The Providence Journal: Car Doctor: Brakes are freezing on daughter's 1990 Dodge RAM truck