135i Racing Brake Piston Upgrade

[chicken-butt]

Any updates on the RB pistons? How are the holding up to track use?

It is time for a caliper rebuild soon and I am considering this upgrade for my HPDE days.

*edit: Oops! Didn't see this thread: Piston upgrade?

[yandy]

Originally Posted by chicken-butt

Any updates on the RB pistons? How are the holding up to track use?

It is time for a caliper rebuild soon and I am considering this upgrade for my HPDE days.

*edit: Oops! Didn't see this thread: Piston upgrade?

I don't have this car anymore, but I had no issues while I had the 135i. The RB pistons went on 4 track days with no issues. Don't expect performance enhancements (ever so slightly), the just don't brake down with heat like the stock ones, which is very important.

Not sure about the quoted thread, mine were just fine.

[dcaron9999]

Thought I would add some more input to this DIY thread ...

I just installed 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 ...

[katsooba]

keep us updated!

[bm49]

I have just bought a manual 2008 135i that will be a daily driver that also gets used at about 10 track days each year. After nearly 20 years of track days in a variety of BMW's ranging from 2002's (including an aftermarket turbo race car) to an E36 328i, I was very excited to discover that 6-pot Brembos were fitted the front of a 135i but bitterly dissappointed to see the posts reporting that such equipment could be so flawed when used with track-capable pads.

From the earlier posts I am leaning towards the RB caliper piston upgrade kit but noted some earlier quality problems. Could I please ask for feedback from anyone who has recently bought an RB kit or the latest thoughts from those supporters of the alternative kit using StopTech parts.

My new car came with a Quaife LSD, KW Clubsport coilover kit and OZ Racing Ultralegga wheels so I am busting to get it to the track after sorting the brakes and maybe a larger capacity oil cooler to keep temps down.

[135TX]

Originally Posted by bm49

I have just bought a manual 2008 135i that will be a daily driver that also gets used at about 10 track days each year. After nearly 20 years of track days in a variety of BMW's ranging from 2002's (including an aftermarket turbo race car) to an E36 328i, I was very excited to discover that 6-pot Brembos were fitted the front of a 135i but bitterly dissappointed to see the posts reporting that such equipment could be so flawed when used with track-capable pads.

From the earlier posts I am leaning towards the RB caliper piston upgrade kit but noted some earlier quality problems. Could I please ask for feedback from anyone who has recently bought an RB kit or the latest thoughts from those supporters of the alternative kit using StopTech parts.

My new car came with a Quaife LSD, KW Clubsport coilover kit and OZ Racing Ultralegga wheels so I am busting to get it to the track after sorting the brakes and maybe a larger capacity oil cooler to keep temps down.

Well you can use the stock brakes at least a few times before they will start to cook dust boots. But I have 12-14 days and no seal issues on stock brakes with track pads.

I bought the RB kit F&R today. They have made some minor changes to ensure no quality issue but I will provide feedback as I use and abuse them going through winter soon as well.

Good luck and enjoy the car!!!

[Ginger_Extract]

I bought the front RB rebuild kit about 3 months ago. I opted to use the standard dust boots, in lieu of the high temp ones, for fear of brake fluid contact. The RB dust boots are garbage, and most of them have either disintegrated, or actually popped off the pistons and become swiss cheese when pressed between the piston and the brake pad. The actual pistons seem fine thus far, but due to the design, leaving the pistons exposed does not instill confidence in keeping grime away from the piston bores and damaging them. Time will tell.
Checked my rear stock pistons the other day and the piston caps are very brittle, and one of them is heavily chipped. Dust boots are toast. Guessing they have about one year of service life left in them before it's rebuild time.

[dcaron9999]

Great input thus far.

Ive ordered front and rear RB pistons, seals, and blue high temp dust boots. Ive rebuild my front + rear calipers, and replaced rubber brakes likes, with Goodridge SS lines about a month ago.

I did about 2-4 lapping days on these thus far, using old Project Mu Club Racer pads. These pads have had outstanding wear rates, and seem to last forever on my stage 2 agressive tuned 135i, that sees the track 2-4 sessions or 20-30 minutes/week. The immediate thing I noticed was how solid my brake pedal ahd become, probably due to SS lines, and fresh bleed more than the pistons.

Lapping season is now over, and I will be doing an inspection of calipers and pads soon. Need to replace my cooling ducts, remove my Ti heat shields, and upgrade my brake fluid. RB claims that TI heat shields are not required due to the piston "ventilated" crown design. Im not convinced of that yet ...

I've noticed that I seem to be boiling my RBF-600 brake fluid sooner than before. I wind up with a softer brake pedal after a few high speed stints at the track. A quick brake bleed fixes the soft, lower-grabbing pedal issue. The possible reason is that the RB SS pistons are letting more heat through, than the stock phenolic top pistons. To be continued ...

Will be back here with more comments after my "end of season" caliper inspection, brake ducting replacement, brake pad lubrication, speed bleeder screws, and brake fluid upgrade to Gulf RF1000 ...

[Faulal]

Did the photos for the original DIY on page one of this thread disappear?
I assume because it was started back in 2013?

[Faulal]

DIY Instructions from Racing Brake on their caliper rebuild kit:
https://www.racingbrake.com/SearchResults.asp?Cat=7123