Thursday, May 05, 2011

Brake Repair

This post intends to relay my experience with brake repair and recommends getting the brakes checked every 30,000 miles, shopping around for repairs and understanding what the measurements on a “free brake inspection” mean.

I am slowly developing experience in automobile maintenance. I have owned two cars in my lifetime. A Chevrolet S-10 that had 173K miles when sold and a Ford Mustang with 56K miles which I am currently driving. Over those 229K miles I have changed batteries, bulbs, belts, an alternator, some suspension parts, spark plugs, spark plug wires and oil. At the shop I have had shocks, brakes, fuel pump, and several other minor jobs done.

I am starting to understand the brake work is a very profitable business. In addition to the dealer, most shops do brakes and Brakes Plus supposedly specializes in brakes. Most service involving disk brakes includes the brake fluid, pads and rotors. There are obviously more complex repairs that are beyond my experience.

Brake Fluid should be the easy one. There is test strip similar to blood test strips that test the copper content of the brake fluid. However, at Midas the measurement was 57 parts per million (ppm) which is OK and at Firestone was 300 ppm which requires replacement. The variation surprised me, but brake fluid can deteriorate at 100 ppm every 36 months so I went ahead and had it replaced at $20 for the parts plus $65 for labor.

Brake pads are also relatively straight forward. This is what is most popular advertised at $97.88 for all four wheels, $79.99 per axle, etc. Brake pad thickness is measured with calipers. They start at around 12 mm (0.50 inches) and need to be replaced when they are worn down half way to 6 mm (0.25 inches). Mine were well below that with one approaching 2 mm. Firestone charged me $130 for the pads and $190 for labor which is high compared to advertised rates, but well within reason for an honest brake job.

I am starting to feel like a lot of advertised rates are a bait and switch as I haven’t met anybody who walked out the door at Brakes Plus only paying $97.88 or leaving Midas only paying $159.98. Browsing Advanced Auto Parts, NAPA and O’Reilly Auto Parts has the parts alone at between $30 and $70 for a set of front or rear brake pads. Labor is based on the flat rate estimate of 3 hours and a straightforward job by a competent mechanic could be done in 1 hour.

Rotors are part of the brake system that do wear out, but should not wear out if the balance of the brake system is maintained correctly. On my car the nominal (starting thickness) starting thickness of the rotors is 1.04 inches on the front and 0.55 on the rear. These are also measured with calipers and I again got different measurements at different shops.  I question Firestone's measurements given the starting thickness on the rotors, but what's a few hundredths of an inch.

Nominal - (1.04) & (0.55)
Midas - (1.018/1.017) & (0.548/0.545)
Firestone - (1.040/1.053) & (0.572/0.579)
Replace - (0.97) & (0.50)

These rotors can be machined to 0.99 inches and 0.52 inches respectively and should be replaced at 0.97 inches and 0.50 inches respectively. Midas recommended replacing all four rotors as machining them was not worth it given the incremental costs of new “premium” rotors at about $70 each. My total brake estimate was $730 at Midas (as I stalled the manager was able to knock $100 off, that is when I decided I should get a second opinion). After researching rotor thickness, there was obviously enough meat on my rotors to justify machining. The complete brake job at Firestone was $430 (two sets of pads, brake fluid, and labor). There was also a $50 rebate and if received my cost would drop to $380 (a $250 savings off of the discounted price at Midas, but comparable as the 4 rotors would be a little over $250).

If I own the car beyond 120K miles, I will expect to replace the rotors but will pay $190 for front and rear drilled and slotted rotors from rather than have the shop provide “premium” rotors.

My S-10 was a little easier to maintain. I recall the initial brake job at about 90K miles costing me $400 for new pads and front rotors which I thought was ridiculous, but may have been right. I then had the pads replaced a second time and this time the rear drum brakes needed new hardware. This marginal cost did not bother me as I was only paying labor on the pads which I recall being reasonable.

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