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Where did all my brake fluid go.

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flyingjohn Avatar
flyingjohn John L
Kent, Maidstone, UK   GBR
1969 MG MGC GT "RTE 935G"
So with spring just around the corner, I thought I would get the old girl out for a spring clean and polish and an engine run etc, while I had a dry day.

Backed out of the garage and whoops, very spongy brake pedal, just enough to stop, but I was glad I wasnt on the road !.

I looked under the car and where it was parked and all seemed o.k until I unscrewed the cap on the brake reservoir, about 1/4inch of fluid - thats all, no sign of a leak !!

But where has it all gone ??

I have topped the reservoir up better braking, but need two of us to bleed the system properly before taking her for a spin.

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gripper180 robert taylor
essex, UK   GBR
hi john.
your brake fluid has either got to be on the floor soaked in to your carpet or in the brake servo. if its in the servo you should see white smoke from exhaust. unless it was leaking a bit before you put car into hibernation and you never noticed it.
bob.

yellercat B R
Little Rock, AR, USA   USA
another possibility is that it is inside of your intake manifold, sucked back thru the one way vacuum valve

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stolizino Avatar
stolizino Silver Member Gary Kinslow
San Antonio, TX, USA   USA
1969 MG MGB MkII "HRH Camille Of Marmite"
1969 MG MGC GT "Percival Snickersnacker"
1974 MG MGB GT V8 Conversion "Grover"
2006 BMW M Roadster "Manfred"    & more
This has become a serious problem for me as well. Brake fluid reservoir will go from full to dry after 2 weeks of daily driving, but even when I see no fluid in the reservoir, the I'm not perceiving any difference in the braking pressure at the pedal. No evidence of leakage anywhere at all. Two servos.

Swamperca Avatar
Swamperca Swamper CA
-, Nor Cal, USA   USA
1969 MG MGC GT "C-Rod"
1971 MG MGB "Rubee"
1974 MG MGB "Groovy B"
Take the vacuum hose and red fitting off the servo air chamber. Use a flashlight and look down inside the hole and you'll most likely see fluid if the servo has gone bad.

In reply to # 3696624 by stolizino This has become a serious problem for me as well. Brake fluid reservoir will go from full to dry after 2 weeks of daily driving, but even when I see no fluid in the reservoir, the I'm not perceiving any difference in the braking pressure at the pedal. No evidence of leakage anywhere at all. Two servos.

jsrivard Avatar
jsrivard Silver Member Joel Rivard
Ramstein, Rheinland-Pfalz, Germany   DEU
1968 MG MGC GT "Maggie"
Check under the master cylinder and it might have made its way down through the pedal box cutout into your carpet.

For a good way to clear air from the top lines without wasting a lot of fluid try this (one-person job):





Cheers,
Joel

MGC Life Blog: https://mgc.is-great.net/
MGC "how-to's" available on YouTube: https://www.youtube.com/channel/UCDMf5tRcUOG0ueyizruhv5w/

stolizino Avatar
stolizino Silver Member Gary Kinslow
San Antonio, TX, USA   USA
1969 MG MGB MkII "HRH Camille Of Marmite"
1969 MG MGC GT "Percival Snickersnacker"
1974 MG MGB GT V8 Conversion "Grover"
2006 BMW M Roadster "Manfred"    & more
So, how does one remove the red fitting? Pry it off? No doubt, I'll break the fitting pipette if I try to pry it off. When dealing with two boosters and I find fluid in the first one I examine is it a good bet both need to be replaced or rebuilt? I may have White Post in my future.



Edited 1 time(s). Last edit at 2018-03-13 05:11 PM by stolizino.

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yellercat B R
Little Rock, AR, USA   USA
Check your plugs.
They will be black if you are burning ze brake fluid.
Your intake mani will also be cruddy if you remove it.
It will need to be cleaned if this is the case.

Swamperca Avatar
Swamperca Swamper CA
-, Nor Cal, USA   USA
1969 MG MGC GT "C-Rod"
1971 MG MGB "Rubee"
1974 MG MGB "Groovy B"
I do both at the same time . White Post did my last set, they have the best customer service and guarantee. The red fitting should wiggle back and forth while pulling outward, try a little lubricant spray.

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ron neal Avatar
Coastal, SC, USA   USA
1962 MG MGA MkII
1968 MG MGC
1969 MG MGC
1969 MG MGC    & more
Gary
FInd a safe place to drive at a moderate speed and hit the brakes hard, then look for white smoke out the exhaust pipe.
White smoke is brake fluid.
Ron

Swamperca Avatar
Swamperca Swamper CA
-, Nor Cal, USA   USA
1969 MG MGC GT "C-Rod"
1971 MG MGB "Rubee"
1974 MG MGB "Groovy B"
The brake fluid test while driving works when you accumulate enough brake fluid in the air chambers, it has a large volume.

stolizino Avatar
stolizino Silver Member Gary Kinslow
San Antonio, TX, USA   USA
1969 MG MGB MkII "HRH Camille Of Marmite"
1969 MG MGC GT "Percival Snickersnacker"
1974 MG MGB GT V8 Conversion "Grover"
2006 BMW M Roadster "Manfred"    & more
Plugs are perfect, no smoke when braking hard unless one counts the panic stop from 50 mph a few months back to avoid a geezer whose Cadillac was stopped at his side street stop sign, then inexplicably pulled out anyway. That was exciting and it did elicit quite a lot of acrid white smoke that seemed to emanate from the entire underside, not specifically the exhaust. Nearly stalled the car and the engine was a bit rough for the next half mile, but I attributed that to me, as I was momentarily contemplating foul deeds.

Master cylinder has no leaks at all.

flyingjohn Avatar
flyingjohn John L
Kent, Maidstone, UK   GBR
1969 MG MGC GT "RTE 935G"
A few things to check at the weekend for me then - thankyou all, lets pray for a nice warm spring day !

7mg2 Avatar
7mg2 Andrew Hardie
Calgary, AB, Canada   CAN
1969 MG MGC GT "Mr "C"
1972 MG Midget MkIII
If there are no visible leaks, the booster(s) will be the most likely culprit(s)



Andy

NAMGBR# 20-7738
AMGCRA# 1678

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