Classic cars forum & vehicle restoration.

[Southernscouse]

Yes with the help of wifey bled the system the old way still no pressure
On Austin site was told to try pumping up pedal when have pressure jam a stick between pedal and seat leave overnight this is were I am at now

[Penman]

Is the fluid level in the reservoir holding up overnight?
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Bristols should always come in pairs.

Any 2 from:-
Straight 6
V8 V10

[alastairq]

Are the rubber seals in the master cylinder the correct way around?
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Dellow Mk2, 1951 built, reg 1952.
Fiat 126 BIS
Cannon special [1996 registered. Built in 1950's]
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Ford Pop chassis, Ashley 1172 bodyshell, in pieces.

[Southernscouse]

So after some advice on the Austin forum. I pumped the pedal until I got pressure then jammed it down with stick against the seat left it for over 48hrs and I now have pedal pressure but low down so I pumped the pedal higher and replaced the stick
I have no leaks but why this works and the three other methods I tried didn?t escapes me

[Southernscouse]

When first removing the stick jamming the pedal I d have pressure but after a short time the pedal goes down to the floor can be quickly pumped up
I think this means I still have air in the system
What are peoples thoughts on the best method to get the system bled

[Southernscouse]

When first removing the stick jamming the pedal I d have pressure but after a short time the pedal goes down to the floor can be quickly pumped up
I think this means I still have air in the system
What are peoples thoughts on the best method to get the system bled

[alastairq]

Still sounds like an issue with master cylinder seal[s] to me....Doesn't matter if brand new, NOS, or re-used ''originals'', failure is just another fact of life keeping old motors going these days.

{I am still amazed at the number of owners of oldies who slap on 'brand-spanking-new' components, then fail to accept that, just because it's 'brand new,' doesn't mean it isn't faulty... ]
_________________
Dellow Mk2, 1951 built, reg 1952.
Fiat 126 BIS
Cannon special [1996 registered. Built in 1950's]
----------------------------------------------
Ford Pop chassis, Ashley 1172 bodyshell, in pieces.

[ukdave2002]

How did all this start? Is this a car that you obtained that never had brakes? Or were the brakes working and these problems have arisen following a routine fluid change or have the brakes developed a fault if so did it happen quickly or got worse over time?

[Southernscouse]

UKdave. It all started when I changed one rear cylinder brakes were working but this one cylinder had a slight leak
After topping up with dot4 fluid and bleeding the rear brakes pedal lost pressure. Then tried vacuum. Air pressure Single operation with one valve bleeding all to no avail
Came to think it was the master cylinder. So replaced the seals went through all the methods again no pressure at pedal by this time I had pumped over a litre of dot4 fluid through all wheels
So still thinking it was the master cylinder i spent ?200 on a replacement went through all methods of bleeding again same result
I can pump up pressure and it will hold when pedal is jammed with a stick for over 48hrs

[alastairq]

Is there a flexi hose to the rear axle brake line?
If so, it's possible the interior has 'collapsed'...preventing proper movement of the brake fluid?
Or, there's a pin hole in the 'rubber?'
Or the couplings aren't seated properly? Not allowing much stuff out, but allowing air to creep in when the pressure is ''off?''
_________________
Dellow Mk2, 1951 built, reg 1952.
Fiat 126 BIS
Cannon special [1996 registered. Built in 1950's]
----------------------------------------------
Ford Pop chassis, Ashley 1172 bodyshell, in pieces.

[ukdave2002]

[V8 Nutter]

If you have drum brakes all round try adjusting them until they lock the wheel, then bleed as normal. finally readjust the brakes, that sometimes works, but as others have said, I would suspect the master cylinder.

[Rusty]

Wow ! You are certainly being put through an ordeal, I don't think I have heard of so many "correct" things being done all to no avail !
Would there be any chance that the push rod that operates the cylinder could be the wrong length? Maybe if the pushrod was "too long" it may hold the piston back far enough that the compensating port is not uncovered, that could cause issues with recharging the cylinder, but with a pressure bleeder attached, the fluid would still be pushed through the system.
I gotta admit, after all you have done, I think most of us are "grasping at straws" for some suggestions as to what could be happening.

[petelang]

I have bled innumerable brake systems over the years and never had a problem, until about 3 years ago when I discovered a pool of fluid under the middle of my Daimler 15. The master cylinder was situated there and the seals had gone. So it was sent off to recondition, being that replacement was unobtainable, and I also did wheel cylinders.
On return, I initially was working alone so rigged up a pressure bleed using a tyre valve and endless hours of bleeding, filling, bleeding, filling, but could get no solid pedal. So switched to vacuum, using a squinty spray bottle pump. That used about a further 2 litres of fluid and achieved nothing. Still no pedal, air still coming out.
I enlisted a friend to pump pedal and switched to conventional methods. Adjusted brakes up to lock drums, did nearest first then working around the car. We were two days at this and eventually, no more air coming, but still a very low pedal.
The only was pedal height could be restored was to pump it like a madman, then hold it down, but once released, it went back to low again. We were totally confounded.
Nevertheless, persevering, using pedal up, pedal down, we persisted, and eventually, with just cracking the bleed open by the tiniest amount when pedal depressed, it gradually came better until I exhausted a full 5 litre can of brake fluid, and TBH my mates leg was dropping off. So we called it a day.
It worked fine ever since!
I have absolutely no idea why, nor do I wish to repeat it again.
Only solace I can offer is try minimal opening of the bleed, not letting all the pressure go, and keep trying.
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Daimler Fifteen 1934 (now sold)
Armstrong Siddeley 15 Long 1933
Daimler V8 250 1969

[alastairq]

Sometimes....the actual position of the bleed screw also affects the ability to expel any air.
Particularly concerning certain clutch slave cylinders....where the bleeder gets positioned , not exactly at the 'highest ' point.
_________________
Dellow Mk2, 1951 built, reg 1952.
Fiat 126 BIS
Cannon special [1996 registered. Built in 1950's]
----------------------------------------------
Ford Pop chassis, Ashley 1172 bodyshell, in pieces.