<VV> brake help

Wed Jan 16 19:33:24 EST 2019

I have a coach business in the UK - I used to have a coach with a 
hydraulic throttle. I switched to silicone fluid, thinking it would be 
better. It started leaking. As a stop-gap, I just topped it up with 
conventional fluid till I could replace the seals. As the silicone fluid 
was replaced (or rather leaked out!) the leak slowed then stopped. I 
never did replace the seals! Never used the stuff since!

On 2019-01-16 18:29, Jim wrote:
> I've replaced everything in the brake system of my '69 in the past, 
> and as
> Hugo says, keep pumping.  You start with the wheel cylinder farthest 
> from
> the master, which, I believe for the rear is on the passenger side.  
> For the
> front, it's also the passenger side.
>
> For the record, I've been using the DOT 5 silicone fluid in all of my
> Corvairs for decades with no problems.  I have, however, replaced all 
> of the
> components when I started using DOT 5. I can't say whether it won't 
> start to
> leak or not if used in a rebuilt system.
>
> Jim Bartasevich
>
>
> There are two kinds of statistics:  the kind you look up and the kind 
> you
> make up. - Rex Stout
>
>
> -----Original Message-----
> From: VirtualVairs [mailto:virtualvairs-bounces at corvair.org] On 
> Behalf Of
> Hugo Miller via VirtualVairs
> Sent: Wednesday, January 16, 2019 6:17 PM
> To: virtualvairs at corvair.org
> Subject: Re: <VV> brake help
>
> If the whole system is empty, you have a lot of air to get rid of, 
> and it
> will take time. Just keep going round each wheel & you should 
> eventually get
> a pedal. One word of caution however - if the master cylinder has not 
> been
> rebuilt, you have to be careful not to press the pedal more than 
> half-way
> down. Otherwise the seals will be venturing into parts of the bore 
> they have
> never seen before, where there might be corrosion etc that will 
> damage the
> seals. I've seen many cars with rebuilt brake systems (except the 
> master
> cyl) suffer complete brake failure shortly afterwards for this 
> reason. Also,
> DoT 5 - is that the silicone stuff? I hate it! It creeps past seals, 
> and
> will leak where the old fluids do not. If everything is new it might 
> be ok,
> but it will find any worn seals long before the old conventional 
> fluids will
> - it's like the difference between water and anti-freeze.
>
>
> On 2019-01-16 17:37, JUDY HOOK via VirtualVairs wrote:
>> I need some help with the brake system on my newly acquired '69, 
>> soon
>> to be my new daily driver.  It has the dual master cylinder on it.
>> This is my first foray into the world of dual master cylinders.  
>> Last
>> evening my wife helped me try and bleed the brakes on said car.  All
>> 4
>> wheel cylinders where rebuilt, all 4 rubber hoses replaced, and
>> numerous pieces of tubing were replaced in the rear hazardous areas.
>> Since I live in PA I decided to try the stainless ones Clark's
>> offered.
>>
>> Since I drove the car home initially, and the brakes seemed to work
>> ok, I chose not to rebuild the master cylinder at this point, 
>> although
>> I did buy a rebuild kit for it, just in case.  I also decided to
>> switch this car to the dot 5 brake fluid like my other 2 since I've
>> never had a single problem with it.
>>
>> When prepping the master cylinder for installation, I emptied it as
>> much as possible of all old fluid.  I then filled it with the dot 5
>> stuff and "bench bled" it with the plastic tubes and cone shaped
>> plugs.  You could see the fluid moving thru the tubes.  After
>> installation, she pumped and pumped and her foot kept going to the
>> floor.  When I would crack a bleeder- nothing.  No rush of air, no
>> fluid- nada.  We did that a couple more times with the same results,
>> however, this time I noticed the fluid level in the front reservoir
>> was down about a half inch.  The rear one never moved.
>>
>>  This time, when checking the bleeders, I got  a teeny puff of air.
>> Then the next time I got a little dripage from it.  But no major
>> squirt like you're supposed to get.  There was no resistance at the
>> front drum, either.  My wife said her foot kept going to the floor
>> with no resistance.
>>
>> Now, my question is this:  Since you could see the fluid moving thru
>> the plastic tubes,  one would assume the master cylinder is pumping
>> fluid like it is supposed to, right?  A mechanic friend suggested it
>> may be  a "trapped" air bubble.  But if it is pumping like normal, 
>> why
>> isn't it compressing the air in the tubes like it is supposed to?  
>> Am
>> I missing something, or doing something wrong?  Or is it simply a
>> matter of the master cylinder not being in as good a shape as I at
>> first thought?  And if the verdict is for the latter, is it that big
>> of a deal to rebuild it, since I've never done a dual one before?
>> Inquiring minds want to know.  Any and all thoughts and ideas
>> appreciated.  Thanks a million in advance.
>>
>>
>> Randy (Cap'n) Hook
>>
>> Hopewell, PA
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