Jump to content

Welcome to RennTech.org Community, Guest

There are many great features available to you once you register at RennTech.org
You are free to view posts here, but you must log in to reply to existing posts, or to start your own new topic. Like most online communities, there are costs involved to maintain a site like this - so we encourage our members to donate. All donations go to the costs operating and maintaining this site. We prefer that guests take part in our community and we offer a lot in return to those willing to join our corner of the Porsche world. This site is 99 percent member supported (less than 1 percent comes from advertising) - so please consider an annual donation to keep this site running.

Here are some of the features available - once you register at RennTech.org

  • View Classified Ads
  • DIY Tutorials
  • Porsche TSB Listings (limited)
  • VIN Decoder
  • Special Offers
  • OBD II P-Codes
  • Paint Codes
  • Registry
  • Videos System
  • View Reviews
  • and get rid of this welcome message

It takes just a few minutes to register, and it's FREE

Contributing Members also get these additional benefits:
(you become a Contributing Member by donating money to the operation of this site)

  • No ads - advertisements are removed
  • Access the Contributors Only Forum
  • Contributing Members Only Downloads
  • Send attachments with PMs
  • All image/file storage limits are substantially increased for all Contributing Members
  • Option Codes Lookup
  • VIN Option Lookups (limited)

Recommended Posts

I installed new rotors and pads on my 2011 CS just over a year ago and also flushed the brake fluid. At that time I switched to ceramic pads to help reduce the dust and knew they wouldn't have as much bite (or dust) as the stock pads and I was OK with that. Over the course of the year the brake pedal became a bit softer but they would bite firmly once in a while.

 

Last weekend I flushed the brakes again and the softness is gone but they do still seem to have more boost at times. I've checked the vacuum pump at the secondary port and it's got plenty with no leak down after the engine is turned off. I don't think it's anything major as no codes are being thrown so I'd tend to rule out a faulty brake booster.

 

The other possibility seems to be a faulty check valve but I can't find any information or part numbers for a replacement if that's indeed what the problem is.

 

Looking for any additional ideas or the check valve p/n.

 

Link to comment
Share on other sites

Is it possible it's just the PSM in combination with driving style (and differing thresholds based on sport/normal)?

The brakes on my 2011 CTT are noticeably different depending on how I drive--there was that ONE time I drove nice and easy in normal mode on the way to church, haha!

 

from the manual pg 190:

 

Examples of PSM control operations 

– Brake system prefilling: 
trans.gifThe brake system is prepared for possible subsequent emergency braking if the accelerator pedal is released suddenly 
trans.gifand quickly. The brake system is prefilled and the brake pads are already applied gently to the brake disks. 

 

 

Link to comment
Share on other sites

No real change in driving going on so I don't think that's it.

 

It'll happen, for example, when I'm just starting out after backing out of a parking space or shortly thereafter. It's happened on an off ramp while just coasting to slow down and then using the brakes with no other cars around. It's also happened on the highway just flowing with traffic and needing to slow a bit due to traffic slowing a reasonable distance ahead.

 

Try as I might I have not been able to reproduce at will nor can I correlate it with any specific activity.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.