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So, my E-brake decided to stop working, right before I need to get the car inspected.. :D I got a video of underneath the car while pulling the e-brake, and it looks like the cable hasn't snapped, as it's moving the mechanism next to the right rear brake. From the video, can anyone give any ideas on why the brake won't engage? I'm guessing it's just something that needs a good whacking, but it's the brakes, so I don't want to whack too hard! :cheesy:

Here's the link to the video: https://vimeo.com/166575005
 

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They might be simply way out of adjustment. As long as the rear pads are not badly worn (and everything involved with the self-adjusters is intact and free to move), it is generally no huge deal to get them working again.


Locate the dust caps on each caliper (they look like bolt heads) and unscrew them.




Behind the cap will be an adjusting screw that accepts a 4 mm Allen wrench.



With the e-brake lever in the fully released (in the down position), the cables should be slack. It is often easier to disengage the cable ends from the slots in the actuator arms.

Then, using the 4 mm key, rotate the adjusting screw clockwise. This will decrease the clearance between the pads and the rotor. Run it all the way in until the wheel cannot be rotated by hand. Then back the adjuster out just a bit; all the while checking when the wheel can move. About an 1/8 of a turn CCW usually works well. At that point, when the e-brake handle is lifted, the pads will clamp down nicely on the rotors - but they won't be so tight that the pads get burnt - or the rotors get blued.


It is always best to install a new set of pads before adjusting the clearance. If you have new pads - that can move freely on their guide pins (and the self adjusters are operational), the specified clearance will be automatically maintained. It helps a lot if you actually apply the e-brake on a regular basis.


In case you're interested, here is what it looks like and how it works:






When the handbrake is applied, the effort required is transferred via cables to the lever of each brake unit (caliper) on the rear wheels. This lever is fixed to an eccentric shaft that presses on a stud when it is rotated. Via the adjusting mechanism, the stud presses on the brake piston and the inboard brake pad. Simultaneously, the entire hydraulic body slides sideways and also presses the outboard brake pad against the brake disc.

When the handbrake is released, the lever on the brake unit (caliper) is returned by the spring and the piston sealing ring in the brake cylinder retracts the brake pads to the rest (brake off) position.

The handbrake system is self-adjusting. As the brake pads wear, the clearance between pads and brake disc is adjusted automatically so that it is kept constant at all times. The adjusting mechanism consists of an adjusting screw and a threaded sleeve. When the clearance reaches a certain limit, the adjusting screw backs off slightly. Self-adjustment 'is therefore carried out in small steps.

When working on the brake system, adjustment should be carried out manually as described in "Adjustment".
 

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Do be careful if messing around with your e brake at the calipers. These are NLA and rebuilts are dodgy. The e brake adjuster parts are no longer made and rebuilds change only the seals, using the original adjuster parts which are now approaching 20 years old. Whacking anything will get you nowhere as the sticking but is inside the piston. How much rear brake pad is left? Check both inner and outer pad thickness. If the adjuster is seized then pad wear might be uneven.

This symptom is one failure mode of the e brake internal adjuster. When it seizes it fails to turn inside the piston. The pad clearance eventually exceeds the stroke of the handbrake lever. The left and right where e brakes are interconnected at the handbrake lever so if one rear brake is dodgy it eventually affects the other. Each has a separate cable but there is a balancing connector at the handle (sone cars use one connecting the wheels directly) and very little movement of the cable is required to take up the specified 2 mm pad clearance.

Before adjusting the caliper manually you can stand on the footbrake pedal and actuate the handbrake lever several times in succession. That may free up the adjuster and take up the clearance.

It is pretty much essential with disc brakes to perform very hard stops every now and again to keep everything from seizing up. The older the brakes get the more important this becomes. Older cars running fewer miles per year get arthritis.
 
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