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I am trying to bleed the brakes on a 1980 TR7 following the workshop manual, starting with the front N/S, Front O/S, rear N/S, fluid is flowing through the pipes. After bleeding a l get some pedal pressure but with the engine running no pedal pressure. My thinking is the master cylinder seals are not holding up under pressure but would welcome any advice before looking at replacing the master cylinder seals.


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Wrong sequence. Always start with the wheel furthest from the master cylinder.

I assume you have a brake servo? Might be a problem with that, otherwise the brake system shouldn't care if the engine is running or not.


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A web search reveals you are not the first to have this on a car. Maybe the first on a 7 though. None of those have a clear resolution.

Can you check with engine off that the brakes work. Im wondering if its actually mechanical binding which is released when the vac is applied. Something like the rubber dust cap on the master cylinder jamming but when vac is applied it "inflates" and frees the push rod. That then reveals another issue which is the soft pedal.

Seems the system is split so the rear take off from the master is for the front wheels and the front take off is for the rears. 

So the fronts are where you should look first as that is the part of the system the vac will work on.

Their is a balance valve between the front and rears but that should behave the same in both situations.

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