Judder / binding of Porsche calipers - fixed
Posted: Mon Sep 11, 2023 3:02 am
Just a quick note to add some information that might be useful to someone in the future via a forum search.
I have Porsche boxster calipers front & back on my ballpoint beam standard beetle. Theses are fitted using adapters to convert the axial mounts to radial. The rears use early 944 caliper mounts.
The brakes are excellent in response and balance, using the stock beetle master cylinder.
However after a few hundred miles, I started to get a harsh judder at very low speeds with very light braking. Mostly around walking /running pace. Never at speed.
The noise was slightly alarming and it seemed to cause the brakes to bind. It only happened with light brake pressure and pressing slightly harder stopped it.
Checks on the pads & rotors found nothing.
After a couple of weeks of this, I figured out it was due to slightly play in the front wheel bearings. I had adjusted the bearing spindle nut to stock amount of play using a dial indicator. I had checked and readjusted, again to stock clearance. However I went back & adjusted to “zero preload” setting, by taking out all slack but leaving the washer free enough to move easily using a small screwdriver (the old school adjustment method).
This fixed the problem and the brakes are back to being fantastic.
So when you have multiple piston calipers, they are very sensitive to front bearing adjustment.
I have Porsche boxster calipers front & back on my ballpoint beam standard beetle. Theses are fitted using adapters to convert the axial mounts to radial. The rears use early 944 caliper mounts.
The brakes are excellent in response and balance, using the stock beetle master cylinder.
However after a few hundred miles, I started to get a harsh judder at very low speeds with very light braking. Mostly around walking /running pace. Never at speed.
The noise was slightly alarming and it seemed to cause the brakes to bind. It only happened with light brake pressure and pressing slightly harder stopped it.
Checks on the pads & rotors found nothing.
After a couple of weeks of this, I figured out it was due to slightly play in the front wheel bearings. I had adjusted the bearing spindle nut to stock amount of play using a dial indicator. I had checked and readjusted, again to stock clearance. However I went back & adjusted to “zero preload” setting, by taking out all slack but leaving the washer free enough to move easily using a small screwdriver (the old school adjustment method).
This fixed the problem and the brakes are back to being fantastic.
So when you have multiple piston calipers, they are very sensitive to front bearing adjustment.