Parking Brake will not engage Left Rear Drum Brake. Fixed!!!

In Nigeria, a road worthiness test is the equivalent of emissions testing or MOT in the US and UK respectively. I had gone in for this annual requirement and to my surprise I failed on account of 3 faults; (1) Difference in rear brakes in excess of 60% (2) Rear left parking brake not working (3) non-aligned tires. Faults 1 and 2 were linked. The 3rd was the least of my worries. In this post I cover the culprit and how I went about fixing the faults.

road worthiness test resultWhat the first 2 faults meant was that the driver side (left) rear brake of my 2003 Accord LX was not working. The first thing I did was to attempt to adjust the parking brake, but alas, the passenger side tire will be rock solid when the parking brake was engaged while the driver side will spin by hand. Something was wrong and I didn’t know what. I hit the web, did all the Googling but all such posts around one rear brake not engaging had no solution documented. Most threads were abandoned.

My car had 234K miles and the last time I changed brake shoes, I didn’t change the return-springs. It is recommended that all return springs are changed when replacing brake shoes.  The real culprit would be revealed when I decided to rebuild my rear brake drums. I needed 2 parts:

  1. Rear brake drum hardware kit: I got this one from Carlson. Obviously, the choice of rebuild kit will depend on your vehicle make, model and possibly trim.
  2. Wheel Cylinders: These are responsible for spreading the brake shoes. I got this Centric brand from Rockauto.com.

Once I started the rebuild process, I spotted a pinhole in the left wheel cylinder. I didn’t observe this in my initial inspection/adjustment. When worn, wheel cylinders will leak internally. Note that I didn’t have brake fluid shortage neither did I have brake fluid on the floor. There was no visible leak. I believe the main defect in the left wheel cylinder was an internal leak. Wheel cylinders have an internal o-ring that will wear with age. Just in case you do not know what a wheel cylinder is, its the shiny metal part with black rubber boots sitting above the orange springs in the next picture!

Once I was done fitting the parts, I bled both sides, adjusted the brakes and this time both sides held as they should.

wheel cylinder

Rebuild complete: new brakes, wheel cylinder and return springs

Next was a 3D alignment and all was good. I got a big fat PASS! They did observe a few minor faults for example missing cotter pins. I have added the missing cotter pins! The only thing left is my lights that have a bit of oxidation. Will have those cleaned soonest.

If your parking brake will not engage a rear drum brake, be sure to check the wheel cylinders. You just might have the same problem I did.

Comments - Have your Say!

This site uses Akismet to reduce spam. Learn how your comment data is processed.