Renewing Brake Master Cylinder
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Renewing Brake Master Cylinder
Going to replace the brake master cylinder on the S as I don't seem to be able to get a firm pedal anymore. Before you ask, done brake bleed several times, calibers refurbed so thinking its the master cylinder.
So my question, when you fit the new one, do you need to put some brake fluid in it first or do you just fit it and then bleed the brakes to get the air out of it?
So my question, when you fit the new one, do you need to put some brake fluid in it first or do you just fit it and then bleed the brakes to get the air out of it?
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96 993 RS
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Re: Renewing Brake Master Cylinder
Just fit it and bleed the brakes through.
Before you change it, have you bled both nipples on your "S" front calipers????
The sad voice of experience from years ago ............
JW
Before you change it, have you bled both nipples on your "S" front calipers????
The sad voice of experience from years ago ............
JW
Life's a single timed run with no practice....
1970 914/6 2.4E/Webers
1970 VW Beetle project
1972 911 Hillclimber 3.2 MFI. Part of the family for 30+ years!
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1970 914/6 2.4E/Webers
1970 VW Beetle project
1972 911 Hillclimber 3.2 MFI. Part of the family for 30+ years!
2006 Hymer Merc Starline 630
2000 T4 Van LPG
2000 Golf V5 Estate GT (Greyhound Transport!)
Re: Renewing Brake Master Cylinder
I have about 4 times now, still no better. Has the calipers refunded last year, pedal was fine before that but don’t seem to be able to get it back
No leaks evident anywhere, so thought good place to start would be the master cylinder
No leaks evident anywhere, so thought good place to start would be the master cylinder
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Re: Renewing Brake Master Cylinder
I would always bench bleed it before fitting a new one to the car. It’s easy, gets rid of 90% or so of the air in the new MC which means you are not pushing all that air into the system at the start and having to ensure you get rid of it all. I did this last year on mine and only had to go round once bleeding each caliper.
Re: Renewing Brake Master Cylinder
Job done, brakes are like night and day now, from very spongy to very hard pedal. Off for a drive now to try them out
72 2.4s
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Re: Renewing Brake Master Cylinder
Excellent!!
JW
JW
Life's a single timed run with no practice....
1970 914/6 2.4E/Webers
1970 VW Beetle project
1972 911 Hillclimber 3.2 MFI. Part of the family for 30+ years!
2006 Hymer Merc Starline 630
2000 T4 Van LPG
2000 Golf V5 Estate GT (Greyhound Transport!)
1970 914/6 2.4E/Webers
1970 VW Beetle project
1972 911 Hillclimber 3.2 MFI. Part of the family for 30+ years!
2006 Hymer Merc Starline 630
2000 T4 Van LPG
2000 Golf V5 Estate GT (Greyhound Transport!)
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Re: Renewing Brake Master Cylinder
Fantastic news.
The simple things you see are all complicated
I look pretty young but I'm just backdated yeah
I look pretty young but I'm just backdated yeah
Re: Renewing Brake Master Cylinder
I have to fit a new MC too - never done it before, or bled brakes before! Sounds like fun!
I don't see a seal on the parts diagrams, where the MC mounts to the bulkhead, but I feel like it should have one - can anyone say for certain whether it needs a seal please?
Thanks for reading and hopefully someone can answer...
I don't see a seal on the parts diagrams, where the MC mounts to the bulkhead, but I feel like it should have one - can anyone say for certain whether it needs a seal please?
Thanks for reading and hopefully someone can answer...
Dean
1973T Targa MFI 334 met blu- under restoration https://www.ddk-online.com/phpBB2/viewt ... 28&t=67060
1980 924 Turbo, blu/grn tartan - restored
1973T Targa MFI 334 met blu- under restoration https://www.ddk-online.com/phpBB2/viewt ... 28&t=67060
1980 924 Turbo, blu/grn tartan - restored
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Re: Renewing Brake Master Cylinder
Never fitted one on my '73T since the first rebuild in 1989. Does seem odd that there is no gasket there mind.
With the splash shield in place, that whole area is very well defended from road splash, so maybe Porsche thought a gasket pointless?
Easy to make one from a suitable material so why not fit one?
With the splash shield in place, that whole area is very well defended from road splash, so maybe Porsche thought a gasket pointless?
Easy to make one from a suitable material so why not fit one?
73T 911 Coupe, road/hillclimber 3.2L
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Re: Renewing Brake Master Cylinder
I’d recommend getting one of the pump-up pressure bleeding kits made by people like Sealey. Makes the whole process easier and very much a one-person operationdeano wrote:I have to fit a new MC too - never done it before, or bled brakes before! Sounds like fun!
I don't see a seal on the parts diagrams, where the MC mounts to the bulkhead, but I feel like it should have one - can anyone say for certain whether it needs a seal please?
Thanks for reading and hopefully someone can answer...
The simple things you see are all complicated
I look pretty young but I'm just backdated yeah
I look pretty young but I'm just backdated yeah
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Re: Renewing Brake Master Cylinder
I'd second this - makes brake bleeding a doddle ...
.
Andy
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Re: Renewing Brake Master Cylinder
BUT remember to seal off the air vent pipe to the side of the brake fluid reservoir, otherwise when you pressurise the reservoir, it will p155 all the fluid out of that vent pipe, into the front frunk area!Lightweight_911 wrote: ↑Fri May 19, 2023 5:51 pmI'd second this - makes brake bleeding a doddle ...
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Re: Renewing Brake Master Cylinder
I probably would have discovered this the hard way, so great tip!! I think I will fit a seal tooNine One One wrote: ↑Fri May 19, 2023 6:38 pm
BUT remember to seal off the air vent pipe to the side of the brake fluid reservoir, otherwise when you pressurise the reservoir, it will p155 all the fluid out of that vent pipe, into the front frunk area!
Dean
1973T Targa MFI 334 met blu- under restoration https://www.ddk-online.com/phpBB2/viewt ... 28&t=67060
1980 924 Turbo, blu/grn tartan - restored
1973T Targa MFI 334 met blu- under restoration https://www.ddk-online.com/phpBB2/viewt ... 28&t=67060
1980 924 Turbo, blu/grn tartan - restored
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Re: Renewing Brake Master Cylinder
I made a little paper gasket, probably not needed as Graham said.
As for the vent tube… no one would be stupid enough to make that mistake with a pressure bleeder would they…
As for the vent tube… no one would be stupid enough to make that mistake with a pressure bleeder would they…
Re: Renewing Brake Master Cylinder
Alternatively, you could just bribe a 19 yr old lad to sit and respond to on/ off, I find this works well but does cost a couple of £££ each timesladey wrote: ↑Fri May 19, 2023 5:12 pmI’d recommend getting one of the pump-up pressure bleeding kits made by people like Sealey. Makes the whole process easier and very much a one-person operationdeano wrote:I have to fit a new MC too - never done it before, or bled brakes before! Sounds like fun!
I don't see a seal on the parts diagrams, where the MC mounts to the bulkhead, but I feel like it should have one - can anyone say for certain whether it needs a seal please?
Thanks for reading and hopefully someone can answer...
72 2.4s
96 993 RS
Series 1 DDK membership card
96 993 RS
Series 1 DDK membership card