[alfa] 105 Benditalia Brake Boosters

[Jon Pike <jhpike@xxxxxxx>]

> Caxambu says: "I suspect one (or both) of my brake boosters leaking
> fluid into the intake manifold. I am continually topping off the brake
> fluid reservoir and never seeing any evidence of fluid leaking to the
> outside. Not at sparkplug looks different than the others. Brake
> function is good.
>
> "What can I do to check this? Do the rebuild kits contain the necessary
> parts to repair this?
>
> "1969, dual servo (Benditalia), floor mounted MC."
>
> ********
> Biba says:
> Have someone follow you to see if there are fairly large puffs of white
> smoke coming from the exhaust.
I would amend this procedure to the following.. 
1. Observe brake booster,  to see where the vac line input is.  (on ATE 
cars its about 10 o'clock from the standing at the front of the car 
perspective)

2. Visualize the brake booster partially filled with fluid, then arrange 
to make the right direction turn that will slosh said fluid towards the 
vac port. 
3. Drive the car sharply thru the turn, and press the brake while making 
the turn.

The combination of centrifugal force, and the brake going in (which 
reduces the volume and pushes the fluid level higher)  will better your 
chances of aspirating some of that fluid down the hose into cyl #4.  
When this happens (if your exhaust system is hot, anyway) you will see 
LOTS and I mean LOTS of thick creamy white smoke.

4. Resist the temptation to lay on demand half block long, 20 foot wide 
clouds of smoke that would make James Bond envious..   (remember kids, 
use this knowlege for Good,  not for Evil..)  ;-)

I fed a mysteriously thirsty brake system for quite a while (probably 
more than 4-5 full tank top ups) before enough leaked into the booster 
to cause this to happen on a turn and brake.

As I understand it, the rear seal of the master cylinder is the 
problem.. I'd guess the standard rebuild kit should have everything..  
Not sure how quickly or if the diaphram of the booster is damaged by 
this,  as I remember my mechanic at the time just did the MC rebuild and 
cleaned out the booster?

Jon
77 Spider
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