[Healeys] Brake issue

[Michael Salter]

Sounds to me as though the master cylinder piston circlip has become
dislodged.

M

On Sun, Jul 28, 2019 at 3:47 PM Michael Oritt <michael.oritt at gmail.com>
wrote:

> In yesterday's fiasco after a few miles of driving the brakes went to full
> lock with no play whatsoever in the pedal, an d I had to pull off the
> road and wait about 30 minutes until the pressure let off enough so that I
> could make it back to the shop.  The consensus opinion, both on this forum
> and on the Healey autox email list, is that there was not enough free play
> in the master cylinder pushrod, thus preventing the MC piston to go past
> the return hole and relieve pressure.
>
> Earlier this afternoon, with everything cool, I put the car up on jack
> stands and while under the car I actuated the brake while spinning the left
> front wheel.  Whatever free play I had--or thought I had--last put into the
> pedal linkage had disappeared and with no free play the slightest bit of
> pedal movement brought about brake activation.  So after loosening the lock
> nut I rotat the shaft about 1/4"-3/8" until there seemed to be the
> appropriate amount of free movement and, again using moving the pedal from
> under the car and spiing the left front wheel, there seemed to be some
> gradual brake actuation.  So I locked the shaft down and went out for the
> proverbial test ride.  At first all seemed good but as the engine warmed
> up and after using the brakes several times with different degrees of
> pressure, etc. I could again feel the brakes begin to drag and by the time
> I got back to the garage the pedal height had changed with all free play
> having disappeared.
>
> I can't help but feel this phenom is--at least partially--related to heat
> transfer into the MC.  It is very warm here in MD and, with the same pedal
> shaft adjustment as yesterday, prior to temperatures going up there did not
> seem to be any issue.  Then again maybe there has been some deterioration
> within the MC and/or debris within the cylinder itself.
>
> Anyway, I will make another attempt at adjustment tomorrow morning and
> report back.  In the meantime thanks for the many helpful suggestions.
> However it appears that more work needs to be done.
>
> Best--Michael Oritt
>
> On Sun, Jul 28, 2019 at 2:25 PM <warthodson at aol.com> wrote:
>
>> Michael,
>> You are correct in pointing out that there is known problem with the 100
>> master cylinders. In addition, inadequate free play adjustment of the 100
>> master cylinder could also cause similar symptoms. Adjusting the free play
>> seems like the easiest thing to check first.
>> Gary Hodson
>>
>>
>> -----Original Message-----
>> From: Michael Salter <michaelsalter at gmail.com>
>> To: warthodson <warthodson at aol.com>
>> Cc: Michael Oritt <michael.oritt at gmail.com>; Oudesluys <
>> coudesluijs at chello.nl>; healeys <healeys at autox.team.net>
>> Sent: Sun, Jul 28, 2019 9:11 am
>> Subject: Re: [Healeys] Brake issue
>>
>> Regarding pushrod free play.
>> Unfortunately the known problem with 100 master cylinders is internal to
>> the cylinder itself and is not resolved by ensuring that the push rod has
>> free play.
>> Roger Moment wrote an excellent, and of course exhaustive,  article on
>> the subject many years back after he encountered difficulties when using
>> silicon fluid.
>>
>> M
>>
>> On Sun, Jul 28, 2019, 9:42 AM warthodson--- via Healeys, <
>> healeys at autox.team.net> wrote:
>>
>> I still suspect the lack of proper free play in the brake pedal & this is
>> the easiest to check. Simply adjust the free play, temporarily, such that
>> there is excessive free play & go for a test drive.
>> Gary H
>>
>>
>>
>>
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