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Brake Master Cylinder Differences?

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5 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW

Discussion summary

YOUR RESEARCHBrake Master Cylinder Differences?

Leading reported evidence

Use 23mm piston, and the turbo

Suggestion or failed attempt

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
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Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion

The standard 996 master cylinder uses a 23mm piston, and the Turbo uses a 25.4mm piston due to the larger calipers.

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Brake Master Cylinder Differences?
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Leading evidence: 'Use 23mm piston, and the turbo' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Use 23mm piston, and the turbo' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.

Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.

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1 matching discussions · 5 captured posts examined · 0 partial discussions

Compare 2 other evidence results

Use 25.4mm piston due

Suggestion or failed attempt

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context

Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion

The standard 996 master cylinder uses a 23mm piston, and the Turbo uses a 25.4mm piston due to the larger calipers.

Original post Read captured discussion
Brake Master Cylinder Differences?

Use on a turbo

Suggestion or failed attempt

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context

Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

So, I'm wondering what it takes (if anything) to adapt the 1040 for use on a Turbo.

Original post Read captured discussion
Brake Master Cylinder Differences?
Frequently discussed actions (3)

These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.

Use 23mm piston, and the turbo

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion

The standard 996 master cylinder uses a 23mm piston, and the Turbo uses a 25.4mm piston due to the larger calipers.

Original post Read captured discussion
Brake Master Cylinder Differences?

Use 25.4mm piston due

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion

The standard 996 master cylinder uses a 23mm piston, and the Turbo uses a 25.4mm piston due to the larger calipers.

Original post Read captured discussion
Brake Master Cylinder Differences?

Use on a turbo

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

So, I'm wondering what it takes (if anything) to adapt the 1040 for use on a Turbo.

Original post Read captured discussion
Brake Master Cylinder Differences?
Coverage and how to read this overview

Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.

5 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.

  • Rennlist: 1 discussions

0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.

0 acknowledgements have no verified action link; they do not establish a repair result.

Generation: 20261026T200546Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

Anyone know the physical difference between the 996 brake master cylinder parts 99635591040 and 99635591050? I know the 1040 is for normally aspirated 996's with PSM (M476) and 1050 is for 996TT with PSM. I ask because the 1040 can be had for $100 to $200. The 1050 is more like $500 to $600. So, I'm wondering what it takes (if anything) to adapt the 1040 for use on a Turbo.

POST 3Original post

The standard 996 master cylinder uses a 23mm piston, and the Turbo uses a 25.4mm piston due to the larger calipers. I believe everything else mounts up the same, so there's a good chance it will be a simple upgrade for Carrera owners. This would essentially would be a down grade for you and other turbo owners though, as you would be moving less volume.

POST 4 / ORIGINAL POSTEROriginal post

ECS, appreciate the feedback. So, the Carrera bore is about 15/16 and the turbo is 1"... The units look the same and should be physically interchangeable, as you suggest. Both have one M10 and one M12 port, which is convenient. Since the stroke is the same, I basically need to determine if a 10% loss in fluid displacement is acceptable as well as living with 10% more pedal travel. Seems like it should be...

POST 5Original post

Quotes source post: 11492228

It's your car and your choice but you will be modifying an excellent braking system and don't know what you will end up with. The master will pump 12% less fluid per inch of pedal travel. Will it bottom out before pumping enough fluid? Your calipers are not the same as the NAs, your car weighs more, goes faster. Most owners want better brakes not worse ...

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