51 Split Window Cabriolet brakes

For Pre A discussions and questions
Post Reply
Message
Author
Mark James Ready
356 Fan
Posts: 51
Joined: Mon Feb 04, 2019 9:16 pm
Tag: Mark
Location: Australia

51 Split Window Cabriolet brakes

#1 Post by Mark James Ready »

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.

User avatar
John Brooks
356 Fan
Posts: 2146
Joined: Tue Jul 08, 2008 11:50 am
Location: Whidbey Island WA.
Contact:

Re: 51 Split Window Cabriolet brakes

#2 Post by John Brooks »

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

62 Roadster
66 912
84 Cab
getting pushed around in porsches since 1965

User avatar
Bil Brown
356 Fan
Posts: 907
Joined: Thu Mar 27, 2008 12:36 pm
Location: Lincoln, NE

Re: 51 Split Window Cabriolet brakes

#3 Post by Bil Brown »

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

User avatar
Vic Skirmants
Registry Hall of Fame
Posts: 9279
Joined: Tue Oct 27, 2009 5:02 pm
Location: SE Michigan
Contact:

Re: 51 Split Window Cabriolet brakes

#4 Post by Vic Skirmants »

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
356 Fan
Posts: 51
Joined: Mon Feb 04, 2019 9:16 pm
Tag: Mark
Location: Australia

Re: 51 Split Window Cabriolet brakes

#5 Post by Mark James Ready »

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

Mark James Ready
356 Fan
Posts: 51
Joined: Mon Feb 04, 2019 9:16 pm
Tag: Mark
Location: Australia

Re: 51 Split Window Cabriolet brakes

#6 Post by Mark James Ready »

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.

User avatar
Bil Brown
356 Fan
Posts: 907
Joined: Thu Mar 27, 2008 12:36 pm
Location: Lincoln, NE

Re: 51 Split Window Cabriolet brakes

#7 Post by Bil Brown »

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

Mark James Ready
356 Fan
Posts: 51
Joined: Mon Feb 04, 2019 9:16 pm
Tag: Mark
Location: Australia

Re: 51 Split Window Cabriolet brakes

#8 Post by Mark James Ready »

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

Post Reply