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Author Topic: Nagging question about Dunlop brakes on a series 1 Sport .  (Read 766 times)
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Derek Creasy
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Posts: 68


Here's to sunnier days


« on: 25 September, 2023, 03:12:45 PM »

Nagging question about Dunlop brakes on a series 1 Sport  .
    The brakes were awful when I got her and so I replaced the m/cyl . and  all wheel cylinders.  Unfortunately  ,  (even more so by the time you finish reading this) , the EBC yellow stuff pads with their solid backs were too wide to fit between the piston and the disc  , so I spaced the cylinders out with a 1mm washer  on each bolt between the cylinder and carrier which gave just enough clearance to get the pads in . The brakes were much better although never inspiring complete confidence.  Pedal  travel  varied often after bleeding many times  , from a 1/3 to Ύ  of the way down before working.. Having spent many, many  hours over the last 18 months changing master cylinders , brake pipes ,  hoses  and  5 litres of DOT 4 , I then accepted that being Dunlop they were as good as they ever could be, non servo,  until…………………… ….by the time I got back from the Dutch Rally (750+ miles), the pedal was almost on the floor when braking hard !  After much thought and clutching at straws  , I decided to remove the spacer washers  being the only alteration made that could think of and that after 12k miles since fitting , they would no longer be necessary .
  Lo and behold  , after one side the pedal was only half way down and harder than ever before and removing those on the other side brought it so high that the pedal  stop  height needed adjusting
Took her out for a run and after getting the pads warmed , I locked the wheels several times which would have been impossible before.  Having asked several people no-one so far can offer an explanation as to why a  1mm further out starting point for the piston should have caused the problem  when it is surely no different to 1mm of pad wear ? and it has to travel up to 10mm to accommodate that .
So relieved that  finally (fingers crossed ) I have really good brakes now but ---------
What am I missing here ?
Addendum:  Went for a really good run today and so much more confident to drive harder . (Goodwood again next year).  Someone asked if I had re-bled the brakes before the improvement and the answer is No , there was/ is no air in the system and never was the problem.
« Last Edit: 26 September, 2023, 03:56:06 PM by Derek Creasy » Logged

2000HF Coupe          1972
Fulvia Sport  1.3S     1968
Delta 3 2.0 Limited   2012
chriswgawne
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Posts: 2077



« Reply #1 on: 25 September, 2023, 04:55:41 PM »

I cant answer your specific question but I can say that I have found Dunlop brakes on Fulvias to be very effective over around 50 years of ownership of different models. What I think is important is that everything is in good condition and also that the master cylinder bore is very highly polished. If not then there can be problems with the insides 'returning to rest' after braking. And also all the seals must be in good condition which goes without saying.
With regard to bleeding the brakes I always used low air pressure into the master cylinder reservoir to push the fluid through (using a modified Gunson setup) although if I were doing the job today I would probably opt for a 'sucker' setup using compressed air drawing the fluid through the wheel cylinder nipples one by one as that system has proved very effective on our old 330k mile Landcruiser.
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Chris Gawne
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