PCA event- s4 front brakes locked
07-22-2022, 04:43 PM
#16
Former Sponsor
There's really not much in the master cylinder to cause the brakes to not release. Single piston seal with a large return spring, for the front brakes.
Most of the time, this issue is either the power brake booster (very common) or the calipers themselves (becoming more common, as these cars age.)
Frequently, these days, the front calipers will "drag" some when they get hot....and fool people into thinking the problem resides there, only.
"Old parts can trick you" is the point, here.
Regardless of the cause, the "locked" brakes will generally release when the car cools down, but there can be some residual dragging.
If the issue is in the booster, the brake pedal will change how it feels as the problem occurs.
I've actually seen the brake pedal "suck down" from a bad booster.
Most of the time, this issue is either the power brake booster (very common) or the calipers themselves (becoming more common, as these cars age.)
Frequently, these days, the front calipers will "drag" some when they get hot....and fool people into thinking the problem resides there, only.
"Old parts can trick you" is the point, here.
Regardless of the cause, the "locked" brakes will generally release when the car cools down, but there can be some residual dragging.
If the issue is in the booster, the brake pedal will change how it feels as the problem occurs.
I've actually seen the brake pedal "suck down" from a bad booster.
