×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Brake Master Cylinder Design in Bosch 5.7 ABS/Stability System

Brake Master Cylinder Design in Bosch 5.7 ABS/Stability System

Brake Master Cylinder Design in Bosch 5.7 ABS/Stability System

(OP)
Question for any Bosch 5.7 experts out there... What is different/unique about master cylinder design in the Bosch 5.7 system that has an ABS pump in the hydraulic block PLUS a separate boost (pre-charge) pump (for stability management)?

Some background... I have a 2001 Porsche 996 Turbo which has the OEM Bosch 5.7 ABS/PSM system. (PSM = Porsche Stability Mgmt) The brake pedal feel is soft and pedal travel is longer than desired. Stock MC piston is 25.4mm. As recognition of this issue, Porsche increased the MC piston size to 27mm in the next generation, the 997. However, Porsche did not use the same ABS system in the 997 (eliminated the separate boost pump).

I installed the 997 MC in my 996. The pedal feel was much improved, but the ABS/PSM system fails to pass readiness tests and is disabled. I'm not a Bosch 5.7 expert, but I've done some digging and come to the working theory that the 997 MC isn't compatible with the Bosch 5.7 system because it does not allow the boost pump to build brake pressure when the brake pedal is not depressed.

My suspicion is the 996/Bosch 5.7 compatible MC has a non-typical bypass circuit. Does this sound right? Is this a well known issue?

Anyway... the point of all this... How do I get a MC with a 27mm piston that is Bosch 5.7 compatible?

Thanks for any insights!

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources

eBook – How to Choose the Correct Corrosion Testing Method
When designing a metal component, engineers have to consider how susceptible certain alloys are to corrosion in the final product’s operating environment. In a recent study by NACE (National Association of Corrosion Engineers), it was estimated that the direct and indirect costs of corrosion in the United States is approximately 6.2% of the GDP. In 2016, that cost exceeded $1 trillion dollars for the first time. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close