Monday, March 17, 2014

Brake Pedal Problems: Pedal Pulsations.

Sorry no posts for a while, but the weather has been poor for shooting so I couldn't test fire my Nano, and there hasn't been much else that I can talk about. I gave Aire Serv my notice and my next endeavor will be fixing appliances. The on call schedule was too much to deal with, as well as the huge burden of responsibility that comes with the job. It was simply time to move on and for now, we'll leave it at that. My Rendezvous just rolled at 166,000 miles last night and for three weeks my brakes have been acting up. I'm going to be needing this beast in a couple weeks while I'm training.

When applying them at high speed, the whole car just shook and I could feel the brake pedal pulsate.  As always, funds are limited and the vehicle is almost 12 years old. Many of the brake parts have already been replaced since I bought the vehicle almost four years ago and have a lifetime warranty.  My time and wear and tear on my body still have a lot to answer for though. Besides, swapping parts to fix a problem is not an option.  The trick is to diagnose this correctly and fix this right while spending as little money as possible.

As always, working on vehicles and especially the braking system needs to be done with great care. Improper repairs can cause death, injury and property damage. Get a service manual for the vehicle you're working on if at all possible (in the case of the Rendezvous, there is no manual available). Replace all questionable brake parts with new or rebuilt ones. This is not the place to save money and when in doubt take to a competent mechanic. I've been fixing cars for three decades and have never had a brake job cause an accident, but there are no second chances if you do. Perform this and other repairs at your own risk.

When making a diagnosis, I could simply take off all four wheels and inspect the rotors. However, this is a helluva job on a sloped driveway. So I can only do one axle at a time and need to start with hopefully the right one; front or rear. Time to collect the facts:
  • The rotors, calipers and pads were done about two and a half years ago on the front axle.
  • The rotor and pads were done on the rear wheels shortly after I bought the car in June of 2010.
  • The braking system is overdue for a flush.
  • The tires are dry rotten, but don't have any belts slipping and still hold air.
  • When braking at low speeds, it stops normally.
  • At higher speeds when the brakes are applied, the car shakes and the pedal pulsates.
  • There is no appreciable shaking at the steering wheel.
  • There is some noise coming from the rear wheel on the left side.
What this tells me is that the rear brake rotors are worn and need to be replaced as a set. The pads and all the hardware must also be done at this time. After all that work, a caliper on the right rear side also locked up and needed to be changed out. This ran me about $140 to fix with 2 rotors, grease, brake fluid, pads, a caliper (yes I did just one), some brake cleaner and a hardware kit. I removed the wheels, calipers, brackets, pads and replaced all with the exception of the caliper on the left side that still works for now. I believe the one on the right would have been fine if I hadn't cocked the piston in the bore, oh well. Even with that it took me an afternoon and now it stops on a dime. If the steering wheel had vibrated, the front rotors would have been the first to go.  Maranatha!

1 comment:

Kenny Isbell said...

Good diagnosis. It’s really scary to have brake pedal problems on your car as it puts you at a very vulnerable point. It may fail any moment and I don’t think anybody wants that. Seeing as the car is already old, you may consider replacing just the pedal part if you don’t want to replace your entire car, though. :D

Kenny Isbell @ Apache Oil Company