[Healeys] Healeys Master brake cylinder replace

[Bob Spidell]

I agree this sounds like a M/C problem, and it's probably moot at this 
point, but there's a quick test to (start to) rule out the servo: 
'Stand' on the brake pedal--pump it up if necessary--when starting the 
car. If the pedal goes down an inch or so when the engine fires and 
vacuum  builds the servo* is likely functioning properly. You can also 
clamp off the vacuum line to the servo and see if braking is affected. 
My BJ8's servo makes a popping noise you can feel in the floorboard the 
first time I apply the brakes (like when backing out of the garage). 
I've never figured out exactly why, but it's reassuring.

Presumably, '0.7 hours' doesn't count 'making a cup,' or having a pint.

* Servos are commonly called 'boosters' outside the LBC community, if 
not functioning there's no boost, so braking will require much more 
effort. A common failure is the gland seal, which keeps fluid from 
entering the vacuum circuit, manifested by white smoke out the tailpipes.

bs

On 6/19/2025 5:40 AM, Alan Wasserman wrote:
> Tom.  First, my diagnosis stems from what I was experiencing.  When 
> first applying brakes, pedal went down more than half way. Two simple 
> pumps and pedal working near top.  No leaks. Visual showed master 
> cylinder looking the 66 years old it was.  The gamble was that the 
> problem might be the servo but if so, breaks won’t properly operate 
> after a few pumps. Secondly I was smart enough to know my mechanical 
> limits and called two friends I have unqualified respect for, Hank 
> Leach and George Baxter. They too felt certain it was the master 
> cylinder.
> Now, your issue is quite different.  First go into the foot pit with 
> your flashlight and focus on cylinder connection to break pedal. Move 
> pedal in and out to see if operates smoothly and without catch.  (This 
> may be the problem??) Check fluid. If all else fails, hopefully our 
> resident experts have sage advice. Good luck and please let us know 
> what was the cause.
> Alan Wasserman
> Alanwassermannc at gmail.com
> 732-887-0742
> www.wassermanstudio.com
>
>> On Jun 18, 2025, at 11:02 PM, Michael Salter 
>> <michael.salter at gmail.com> wrote:
>>
>> 
>> The time was 0.7 hours Alan (42 minutes)  as I recall. Unfortunately 
>> I have misplaced my " Austin Healey 3000 Mk III Warrenty Repair Times 
>> Book" so can't confirm that my memory of that is actually correct 
>> however, BMC were renowned for their "stingy" warrenty times. The 
>> time allowed for re & re of the engine was only 5.4 hours!!
>>
>> M
>>
>> Get Outlook for Android <https://aka.ms/AAb9ysg>
>> ------------------------------------------------------------------------
>> *From:* Alan Wasserman <alanwassermannc at gmail.com>
>> *Sent:* Wednesday, June 18, 2025 7:10:15 PM
>> *To:* Michael Salter <michael.salter at gmail.com>
>> *Cc:* Alan Wasserman <AlanWassermanNC at gmail.com>; Healeys 
>> <healeys at autox.team.net>
>> *Subject:* Re: [Healeys] Healeys Master brake cylinder replace
>> My guess Michael, is that “.07” is NOT for a BJ8.  Perhaps for the 
>> 100’s that you usually work on.  Impossible to do in .07 as just to 
>> bleed the cylinder and brakes it will take a good 30 minutes +-. 
>>  Unless there is some very special tool to handle this job….
>> Hope all is well with you and family.
>>
>>
>>> On Jun 18, 2025, at 6:20 PM, Michael Salter 
>>> <michael.salter at gmail.com> wrote:
>>>
>>> Seem to remember that the   time was 0.7 hrs which of course 
>>> included bleeding and a road test.
>>>
>>> M
>>>
>>> Get Outlook for Android <https://aka.ms/AAb9ysg>
>>> ------------------------------------------------------------------------
>>> *From:* Healeys <healeys-bounces at autox.team.net> on behalf of Alan 
>>> Wasserman <alanwassermannc at gmail.com>
>>> *Sent:* Wednesday, June 18, 2025 3:27:29 PM
>>> *To:* Healeys <healeys at autox.team.net>
>>> *Cc:* Alan Wasserman <AlanWassermanNC at gmail.com>
>>> *Subject:* Re: [Healeys] Healeys Master brake cylinder replace
>>>
>>>
>>>   Re Master break cylinder replacement:
>>>
>>> I had reported a few weeks ago that I was about to embark on 
>>> replacing my master brake cylinder on my ’66 AH 3000,  .  FYI, for 
>>> those who have never…the simple explanation:  involved in only four 
>>> /*simple */bolts/nuts (and then to bleed the cylinder and brakes). 
>>>  The “/simple/” four nuts/bolts took approximately 3 hours…YES< 
>>> THREE HOURS!!.  It is impossible to get to the cylinder without 
>>> removing the back air filter (which by itself is not a simple task 
>>> without the right tools).  Once your filter is off, it still 
>>> requires both a bent small wrench and also an articulating socket, 
>>> small arms and hands.  Also, a tip…before inserting your cylinder 
>>> into the firewall hole, slide down the protective rubber, squeezing 
>>> in the cylinder and than, while in the foot pit, slip the rubber end 
>>> into the hole before fastening the cylinder to the side of the brake 
>>> pedal.  When fastening the cylinder to the firewall, do not confuse 
>>> the bolt for the airfilter. After bleeding the brakes, take a spin 
>>> and bleed one more time.  I think it easier to replace a steering 
>>> wheel and dealing with the traficator.  Anyway, I hope this helps 
>>> someone.
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