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Re: Brake Trouble! UPDATE!

To: "John Roberts" <robe3099@bellsouth.net>, <mgs@autox.team.net>
Subject: Re: Brake Trouble! UPDATE!
From: "Paul Hunt" <paul.hunt1@blueyonder.co.uk>
Date: Wed, 11 Oct 2006 09:16:05 +0100
Thanks for the recap.

Sounds like a massive amount of air in the system then, or possibly faulty 
seals in the master leaking back.  I've no experience of dual braking 
systems, let alone the particular model on your Midget ) the MGB had three 
different systems over the years).  With a single circuit system a faulty 
seal could allow the pedal to sink without applying sufficient pressure, but 
would not be spongy i.e. the pedal bouncing back under your foot.  Air in 
the system is felt as a bouncy pedal, i.e. it is like pressing down on a 
strong spring.

I seem to recall you couldn't get fluid out of a rear nipple?  That is 
definitely the first thing to sort out, without being able to bleed all four 
nipples you are wasting your time looking at other things.  On the MGB, if 
just one rear nipple is affected, this can be one of the horizontal pipes 
along the axle having been crushed from being strapped or chained down to a 
trailer.  If nothing from either rear nipple then possibly the rear flex 
hose delaminating internally and acting as a check valve, or the main pipe 
from front to rear being crushed or blocked.

I'm not sure how air or a faulty seal affects a dual circuit master. 
Possibly the working circuit would give the normal feel to the pedal meaning 
that the faulty circuit, whether it be due to air or a faulty seal, would 
feel exactly the same either way.  However if the pedal is going to the 
floor then it doesn't seem to be developing enough pressure in *either* 
circuit.  And if this is accompanied by getting fluid out of all four bleed 
nipples, then I would have to conclude a major problem inside the master.

PaulH.



----- Original Message ----- 
> First it is a 71 Midget that I am talking about.
>
> The pedal goes to the floor.  No pressure builds up when I work the pedal
> several times in a row.
>
> I am getting strong fluid flow from both front caliper bleed nipples.  I
> have bled the front brakes using a two-man system.




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