Danyol

I have an '03 X50TT with PCCB brakes and currently have 28k miles on the car. Over the last few thousand miles squealing from the brakes became intolerable. Looking at the manual there are "vibration dampers" attached into each piston with a retaining spring and a sticky pad to the back of the brake pad. I replaced these dampers and I have peace again! Parts (Front Calipers) Damping plate X12 996-352-086-01 Spring Plate X1 996-351-959-30 Procedure (appx. 1 hr) 1) Jack front of car and remove wheels (remember to use assembly aids to protect PCCB disc) 2) Suck out some brake fluid from the master cylinder with a 50 ml syringe (or turkey baster) 3) Spread pads apart pushing pistons back into calipers (I used a small monkey wrench as a spreader) 4) Disconnect pad wear sensor and open 2 wire ties (attached to brake fluid tube) to get the wire free 5) Remove screw from retaining pin, use a drift pin to push it out. Careful not to damage sensor wires. 6) Pull out 2 pads together, place on bench. Lever out old damper plates out of the 12 pistons with a screwdriver. Use the opportunity to blow out all the brake components with compressed air (use a dust mask and eye protection). 7) Clean the back of the brake pads with alcohol on bench 8) Pull sticky pad off new dampers and push spring side into piston. Note - the ones on the smaller pistons need to have the cutout facing the calipers internal pin or they will be bent 9) Use new spring and pin, pass pad sensor in retainer in spring (note orientation of spring., one side of car is reversed from the other. 10) Put pads back being careful to hug the disc, push spring in and replace retaining pin. Ensure pads are seated, install screw on retainer and torque to 25 Nm 11) Pump brake pedal to reseat break pads and allow sticky pads to adhere. 12) Top up brake fluid, replace wheels (torque to 97 ft lbs) Test drive and enjoy the quiet braking!

Common Symptoms - Hard pedal particularly with engine off, vibration and inexact point of engagement Tools 27mm open ended wrench (small head - I ground down an old wrench), 10mm socket Materials Accumulator 997-334-166-00, Hydraulic fluid Pentosin CHF 11S (or CHF 202) - Pump the clutch 25 times with the engine off to relieve any residual pressure in the system - all 4 wheels off the ground on jack stands or a lift. Easier to remove driver's side rear tire for better access if you're on stands. - Remove the rear cross brace (drawing below) - Remove hose clamp assembly directly below accumulator (10mm socket) - Unscrew ball (27mm open, small head or ground; see picture) have a cloth around it to catch any spills, Pentosin is nasty stuff, it will eat the rubber hoses (It is also very flammable!) - Install new ball & tighten to 22 ftlbs (I did it with my modified wrench to "just enough") - Reinstall hose bracket & reattach hoses - reinstall cross brace, torque to 48ftlb - pump clutch, check for leaks - bleed clutch using a pressure bleeder on front reservoir, bleeding at the slave cylinder (no more than 10 psi) - run engine 20 secs, turn off and check fluid level under cover in luggage compartment and in the power steering pump. - run engine pump 10 times to bleed, turn off check levels again.