Raffi's 62 Brakes

["David Sherratt" <dave-tracy@xxxxxxxxxxxxxxxxxxx>]

The repair of the oval brake booster is quite simple.  However this must be
conceived as only a temporary repair.

The oval brake booster is a very simple piece of kit.  It is basically just
a cylinder with poppet valves and a large neoprene diaphram and piston.  It
is nine times out of ten the neoprene that wears.  The centre of the
cylinder has a shaft that runs through the centre of the neoprene diaphram
and piston.   If you disassemble an oval cylinder you will find all the
poppet valves towards the front and a valve block that's held in position by
two split pins or Salock pins as we call them in England.  If you remove the
two pins you can slide the valve block off the end of the shaft and then
remove the diaphram and piston.  If you inspect the diaphram where it is in
contact with the shaft, you will find that it has worn.  The best way of
describing it is that the contact edge of the diaphram should look like and
oil seal with a raised edge on the internal diameter.   What I did with mine
was to find an O ring and bond it with an epoxy resin to the diaphram so it
made a new contact surface to the diaphram.  Also at this stage there is a
nylon washer that also causes wear, you will need to check that.  Prior to
reassembly I coated the shaft liberally with rubber grease thats used in
brake cylinders, etc.

Please bear in mind that this is only a temporary repair, even though the
epoxy resin I used had a 1200 psi tension.  I repaired the brake booster 18
months ago and its still working as good as new now..

When the brake booster is disassembled, only use alcohol to clean the brake
parts and poppet valves and the inside of the actual cylinder.

Hope this is of help.

Dave
60 Le Baron
England
-----Original Message-----
From: mopar2@xxxxxxxxxx <mopar2@xxxxxxxxxx>
To: mailing-list@xxxxxxxxxxxxxxxx <mailing-list@xxxxxxxxxxxxxxxx>
Date: 13 April 2002 14:34
Subject: Re: IML: Raffi's 62 Brakes


>The combination of the hissing & rough idle suggests a vacumm leak.Check
the
>hoses from the booster to the manifold for possible leaks, if none there,
it
>could be the booster. Many have said that once brake fluid gets on the
linings,
>its impossible to remove it all & problems will result, but this doesn't
sound
>related to your current problem.
>John
>
>Raffi Kondy wrote:
>
>> Hey list,
>>
>> I recently had my wheel cylinders replaced because the originals were
>> leaking brake fluid, and my neighborhood mechanic, a very experienced
>> mechanic at that, put them in but noticed a problem.  He said that when
he
>> tested the  brakes, after coming to a stop with the pedal fully engaged,
the
>> brakes seem
>> to disengage a little, and the car moves forward slightly until you apply
>> more pressure to the brake pedal.  He seems to think the problem might
>> be in the brake shoes, which got a little wet from the brake fluid
leaking
>> on them, but which he cleaned and checked and seems to think are ok.  He
>> believes that everything else is ok on the brakes.  I tested the car, and
>> felt like the brakes are better now than whenever I had driven the car
>> before (I have been driving it about 9 months now), but I did notice
>> what he was talking about.  I don't think that this is dangerous, but it
>> seems odd that when you push down on the brake pedal and the car stops,
>> its as if you need to push down a second time to keep the car from moving
>> slightly.
>> I know I'm not doing a great job of describing this problem, because it
>> really needs to be experienced to be understood.
>>     Could the problem lie with the brake vacuum booster?  Maybe it leaks
>> and doesn't give the full boost when you put your foot down on the pedal
all
>> the way.  It does seem to hiss a little when the car is in N and you
>> push the pedal down all the way to the bottom.  Anyway, if you have ever
had
>> this problem, maybe you could help.
>>
>>     Also, I had the mechanic check the choke and the carb, the car wasn't
>> idling properly, and he changed the idle speed to about 700, which seems
>> a bit high according to specifications.  Is this unwise? It feels better
>> than before. Thanks,
>>
>> Raffi in SF
>> 62 Crown Coupe
>>