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dt4
Monza


Joined: 16 Mar 2016
Posts: 186
Location: Leeds


PostPosted: Fri Jan 18, 2019 2:30 pm    Post subject: Spongy brakes Reply with quote

The car has been in the garage since the beginning of November whilst I have sorted out exhaust clamps and the oil pressure sender
I took it out today to see what readings the oil pressure gauge gave whilst running and to get to temperature etc....
One thing I noticed was the brake pedal was soft and needed a couple of pumps to get a decent peddle feel but it kept going back to spongy

What are the likely causes and remedies please?
It was all fine before going in the garage

cheers
 
  
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Stoo.c
Monza


Joined: 07 Apr 2014
Posts: 205
Location: Hertfordshire


PostPosted: Fri Jan 18, 2019 2:45 pm    Post subject: Reply with quote

Well if it keeps going spongy and needs pumping up then either you have a small leak in a pipe or hose somewhere or the master cylinder itself has failed (the seals).

Have a look closely at all the hoses and pipes and see if there is a slightly wet spot. It will most likely be a very small pin hole if indeed it is a leak.
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02 996 C4S
93 Skyline R33 GTS-t
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Luddite
Nürburgring


Joined: 18 Dec 2018
Posts: 410
Location: Scotland


PostPosted: Fri Jan 18, 2019 3:13 pm    Post subject: Reply with quote

dt4, there are numerous causes for a spongy brake pedal, though given it was fine the last time you drove it, and that it has been laid-up for some months..hmm.

I would look for the easy stuff first.. I have had the same issue in similar circumstances on an SC, caused by a brake piston in a rear calliper that seized up while lying idle (in a two piston calliper)

Wheels off, I spotted it by having a friend pump the pedal while I went round the discs looking at the callipers and saw one of the discs being deflected slightly to one side every time the pedal was pressed... the spongy feeling was the disc flexing and springing back against the one operational piston that was causing it to deflect.. Freed off the piston and all was well.

Flexy hoses can if damaged expand like a balloon to give a similar effect.

If that does not work and you have brake hose clamps you could go round the flexy pipes clamping them off in turn to see if your problem is related to a single caliper..?

Good luck and please let us know how you get on.
 
  
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dt4
Monza


Joined: 16 Mar 2016
Posts: 186
Location: Leeds


PostPosted: Fri Jan 18, 2019 3:25 pm    Post subject: Reply with quote

Thanks for the replies
Ill start by checking the hoses
 
  
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