Project BMW 335i
PART THREE: With a new set of rear brake pads and a wear sensor, Rob Hawkins visits his local garage to help fit them and to also fix the inefficient handbrake.
Realising my attempts in the last issue of CM to adjust and improve the efficiency of the handbrake had failed miserably after a mere 64 miles, I turned to my local garage, MJ Motors, for help. Fortunately, mechanic Jacob knows every inch of most BMWs, so he soon had a plan of action. As mentioned last month, after speaking to CM’s Steve Rothwell, the handbrake cables can stick, but also the mechanism that’s fitted between the two brake shoes and operates them, when the respective cable is pulled, can seize.
Having realised we needed to fit a new wear sensor on the offside rear brakes (the old one had been detached and damaged), it was wise to replace the rear brake pads at the same time. So, there was a growing list of rear brake-related jobs.
Unfortunately, as you’ll see over the following steps, we didn’t discover any major calamities that would help to solve our handbrake issue. The handbrake cables weren’t sticking – they could be pulled at each rear brake and when the handbrake lever was applied, the cable was pulled through. As for the mechanisms, they were very rusty-looking, but hadn’t seized. We decided to replace them anyway.
Shoe adjusting
One point that we felt could have made a difference concerned the method of adjusting the handbrake shoes. Jacob explained that it’s essential to back off the handbrake cable (also called service mode) to ensure it’s slack and doesn’t interfere with the shoes when adjusting them. He did this at the handbrake lever, pushing the end of the cable with a screwdriver to lock it and slacken the cable. Once we had adjusted the handbrake shoes, the end of the cable was released.
When adjusting the handbrake shoes with the cable backed off, Jacob wasn’t too concerned that the discs felt as though they were dragging (after he had adjusted the shoes until they locked, then backed them off by a quarter of a turn). He was confident the slack in the cable would reduce the amount of drag (once the cable was released), and it did.
Once the rear brakes had been reassembled with the new pads and wear sensor, there was only one way to tell whether the adjustments had worked or not. The BMW was moved to the MOT ramp and the rear wheels positioned over the brake rollers. The handbrake efficiency was tested and, to our surprise, it wasn’t as good as expected. It was sufficient to pass the test, but everyone was expecting it to be much better. Perhaps we may need to replace the handbrake cables, even though they seem to be moving freely.
Whilst the mystery surrounding the handbrake continues, we now have bigger problems to solve. An ABS warning light has appeared on the dashboard.
