Just wanted to share a few observations from mucking around with my parking brakes.
My CAV has PBR parking brake calipers set on the front side of the rear discs. These calipers are floating calipers and come from (I believe) certain GM cars of the 90's (transam? corvette?). In any case, diagram is below and they're a decent design.
Essentially, they are self adjusting. There is a brake pressure port at the back side which pushes a piston against the back side of one of the pads when the brakes are applied, and a mechanical lock is applied via the parking brake cable. The cable attaches to a pivot arm which is connected to a metal ring wrapped around the shaft of the piston. When the cable is applied, the pivot arm extends one side of the ring which then binds/clamps/locks on the shaft and extends the shaft further providing a lock on the disc. It's not very intuitive when you look at it. You actually unscrew the adjuster screw to increase the throw.
That all works fine, except that part of the back side of these calipers had been machined off on my car. This meant there's no port for brake pressure (or a bleed port). I imagine this was done so that the p-brake caliper clears the shock/spring without interference. Because there's no port for brake pressure this means that these calipers are basically NOT self adjusting, and need to be adjusted with shims or new pads when the old pads wear. I'm not sure if all/many CAV came equipped this way, but mine did.
I a) made a shim to go behind the outboard pad, b) ordered some new pads from online, and c) adjusted the adjustment screw outwards (to increase the locking travel of the pivot arm).
These calipers are a bit of a compromise obviously. Does anybody know of a nice elegant/simple mechanical locking parking brake I might use instead?
Thanks.
My CAV has PBR parking brake calipers set on the front side of the rear discs. These calipers are floating calipers and come from (I believe) certain GM cars of the 90's (transam? corvette?). In any case, diagram is below and they're a decent design.
Essentially, they are self adjusting. There is a brake pressure port at the back side which pushes a piston against the back side of one of the pads when the brakes are applied, and a mechanical lock is applied via the parking brake cable. The cable attaches to a pivot arm which is connected to a metal ring wrapped around the shaft of the piston. When the cable is applied, the pivot arm extends one side of the ring which then binds/clamps/locks on the shaft and extends the shaft further providing a lock on the disc. It's not very intuitive when you look at it. You actually unscrew the adjuster screw to increase the throw.
That all works fine, except that part of the back side of these calipers had been machined off on my car. This meant there's no port for brake pressure (or a bleed port). I imagine this was done so that the p-brake caliper clears the shock/spring without interference. Because there's no port for brake pressure this means that these calipers are basically NOT self adjusting, and need to be adjusted with shims or new pads when the old pads wear. I'm not sure if all/many CAV came equipped this way, but mine did.
I a) made a shim to go behind the outboard pad, b) ordered some new pads from online, and c) adjusted the adjustment screw outwards (to increase the locking travel of the pivot arm).
These calipers are a bit of a compromise obviously. Does anybody know of a nice elegant/simple mechanical locking parking brake I might use instead?
Thanks.