51 Split Window Cabriolet brakes

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Mark James Ready
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51 Split Window Cabriolet brakes

#1 Post by Mark James Ready » Fri Jan 21, 2022 8:41 pm

During mountain drive found brakes wanting. Very poor stopping power. Realise drum brakes and 51 technology but have driven 356 As with drums that stop a lot better! Pads and drums are in good condition. Any suggestions for improvement.

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John Brooks
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Re: 51 Split Window Cabriolet brakes

#2 Post by John Brooks » Fri Jan 21, 2022 9:01 pm

Mark
Those old iron drums and aluminum rings are not modern brakes. If they are fading and you can't get them to lock up, i would suspect a leaking or bypassing master cylinder. If all the drums are dry and they have good shoe contact areas, I would just rebuild the master cylinder and try again. I have not had a split window is over 50 years but I do not remember much difference between them and a T-1 or T-2 when stopping. My test is getting up to 25-30 MPH then hands off and stomp hard the pedal to stop. See if it pulls and all 4 wheels will lock up.
You also may have a ballooning flex line that is swelling up with pressure. That can prevent a wheel or two from locking up.
John Brooks

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bil brown
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Re: 51 Split Window Cabriolet brakes

#3 Post by bil brown » Fri Jan 21, 2022 10:46 pm

If you`re going to drive the car very much.....I would put on a set of 356A brakes, they`ll bolt on.....restore the og set and shelve`m......BTW......what engine is in it?
Bill Brown

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Vic Skirmants
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Re: 51 Split Window Cabriolet brakes

#4 Post by Vic Skirmants » Sat Jan 22, 2022 8:39 am

John Brooks wrote:
"You also may have a ballooning flex line that is swelling up with pressure."
I have NEVER heard of a ballooning flex line. Swelling up inside, yes; ballooning, no.
There is a huge difference between the small VW brakes versus the 356A brakes.

Mark James Ready
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Re: 51 Split Window Cabriolet brakes

#5 Post by Mark James Ready » Sat Jan 22, 2022 9:40 pm

Thanks John and Bill,
Will try those suggestions. Original engine 1300cc. RHD, first Porsche into Australia along with red coupe.

Mark James Ready
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Re: 51 Split Window Cabriolet brakes

#6 Post by Mark James Ready » Mon Jan 24, 2022 8:58 pm

Found the problem. Faulty slave cylinder. Also explains why hub getting hot. Brake pads not releasing after application thereby continuing to rub on drums. Will now check master cylinder.

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bil brown
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Re: 51 Split Window Cabriolet brakes

#7 Post by bil brown » Mon Jan 24, 2022 9:09 pm

Now would be a good time to rebuild the ENTIRE system, which is the only way to approach failing brake parts...... if you`re going to drive it.
Bill Brown

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Re: 51 Split Window Cabriolet brakes

#8 Post by Mark James Ready » Wed Jan 26, 2022 1:49 am

Yes that's the plan,Bill. All the lines and master cylinder.

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