[Healeys] Brake pedal problem

[Bob Spidell]

Theoretically, I suppose. The servo has both a 'slave' cylinder, driven 
by the M/C, which gates atmospheric air or engine vacuum to the large 
canister for braking assist or normal running, respectively, and a 
'master' cyl. that provides boosted pressure to the wheel cyls. courtesy 
of the air/vacuum pressure differential. A bad seal on the master cyl. 
in the servo /might /cause something similar, though I've not heard of 
this happening, so I can't say what the symptoms would be (though it 
would likely result in really poor braking and possibly a squishy 
pedal). Air in the system or an issue in the M/C is more likely. The 
most common failure of the servo I've seen or heard of is from the 
'gland' seal that seals the piston shaft from the vacuum/air cylinder; 
when it hardens, cracks or tears brake fluid will be sucked into the 
intake manifold and you'll have a new pope.

bs

On 5/21/2025 6:00 AM, warthodson at aol.com wrote:
> Is it possible for the brake booster to produce these symptoms?
> Gary Hodson
>
> On Tuesday, May 20, 2025 at 11:08:52 PM CDT, Bob Spidell via Healeys 
> <healeys at autox.team.net> wrote:
>
>
> I drove my BJ8 over 2,000 miles on a road trip with a similar problem, 
> though it was more consistent. On teardown of the M/C I found that the 
> seal on the 'foot valve' was damaged. This is a seal that closes the 
> feed line to the reservoir when brakes are applied. Simple test: Have 
> someone work the brakes as you closely watch the fluid level in the 
> reservoir; if it rises or ripples when brakes are applied that's your 
> problem.
>
> On 5/20/2025 1:20 PM, Richard Antal via Healeys wrote:
> Greetings Healeyphiles,
>      After a long winter's rest, I drove my BJ8 for the first time 
> this year and noticed immediately that I had to depress the brake 
> pedal far down before braking began, but if I pumped the pedal a few 
> times the brake pedal commenced functioning more promptly. This 
> improvement was fleeting but reproducible. The brake fluid reservoir 
> is topped off. What might be the cause and solution of this problem. 
> Thanks for all help.
> rich antal
>
> _______________________________________________
> Support Team.Net http://www.team.net/donate.html
> Suggested annual donation  $12.75
>
> Archive: http://www.team.net/pipermail/healeys 
> http://autox.team.net/archive/healeys
>
> Healeys at autox.team.net
> http://autox.team.net/mailman/listinfo/healeys
>
> Unsubscribe/Manage: 
> http://autox.team.net/mailman/options/healeys/warthodson@aol.com
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://autox.team.net/pipermail/healeys/attachments/20250521/030fb8ec/attachment.htm>