View Single Post
      09-28-2015, 11:09 AM   #19
dcaron9999
Major
dcaron9999's Avatar
Canada
157
Rep
1,409
Posts

Drives: 2011 135i M package
Join Date: Jan 2010
Location: Mirabel, Quebec

iTrader: (0)

I finally decided to purchase front+rear RB SS pistons, with high temp dust boots. The components are of good quality. As I was opening the brake lines, I also bought SS brake lines for a different manufacturer. I set aside one full day, and worked on one corner at a time, starting with the simpler rear passenger side. The driver side mid lines (two short lines) are a royal PITA due to limited space (between chassis and subframe).

For the caliper rebuild, I use two work benches, and two sets of vinyl gloves to prevent contamination of high temp silicone dust boots (incompatible with brake fluid) and to keep caliper bores and pistons dry and clean.

#1 - First bench to dismount old pistons and clean everything up, including cylinder seal grooves, and dust boot cavities. Prior to cleaning, it is best to stick a piece of paper towel down into each cylinder to prevent debris from creeping in there. Plan for a ton of brake cleaner fluid and paper towels. Compressed air helped to blow any remaning debris out, and speed up the drying process.

You should have seen the surface of the stock pistons - they had grime on them, were a bit scuffed likely because of the dirt infiltration due to the damaged dust boots. Some of the piston phenolic plastic tops (especially outer ones were crumbling and would turn to dust at the slighest contact. One of the piston tops fell off when I injected compressed air into the caliper.

#2 - Second bench to mount new pistons, seals, and boots. Use plenty of light, and inspect inside of caliper cylinders, grooves, cavities, for any sign of debris or dirt. Call me anal but I used a different pair of gloves at this point, to keep everything clean and avoid contamination. This is where I applied the supplied high temp grease onto the seals, and upper cylinder walls. I mounted the dust boots onto the piston prior to insertion into cylinders.

Braking now feals a lot more predictable and solid on the street, but I will confirm at the track this week. There is no longer a trace of sticky pistons and squeaking pads. Brake rotors are more shiny due to strong and even pressure exerted by pistons on the brake pads, especially in the rear.

Should have done this earlier ... This rebuild will give the 6-piston front and 2-piston rear stock calipers a second life, for a fraction of the price of two BBK's ...
__________________
2011 X3 35i with M pack + 2011 135i w/6SPMT | 255 square tire setup | Quaife 3.46 LSD | Diff lock down bracket | Bilstein B8+Swift SpecR springs+H&R FSB | CDV delete | BMS Oil Tstat bypass | ER FMIC & CP | N54Tuning DP | GC Street Camber Plates | M3 FCA +guide rods+RSFB's+Tranny mounts | Manzo toe arms | Cobb Stg2 agressive tune | Hawk DTC70 brake pads | RB SS brake pistons | Goodridge SS brake lines | Custom brake cooling ducts

Last edited by dcaron9999; 09-29-2015 at 08:12 AM..
Appreciate 1