Bleeding Brakes

[Johnny America]

Hi, question for the collective.
Are bleeding the brakes on a +2 prone to any issues. I’ve rebuilt my master cylinder and can’t seem to get a good bleed.

Starting at the rear and then the fronts I have bleed twice. I get a hard pedal when bleeding then the pedal goes soft. And needs a couple of pumps before going hard.

What am I missing?
It’s an early +2 with a single circuit and Lockheed servo unit.

Thank you.

[TonyA]

When this happened to me I was advised that the 'return' seal in the MCylinder wasn't sealing..sometimes it's poor quality ' modern' (Chinese) rebuild kits, sometimes the bore in the Mcylinder is worn and won't fully seal, maybe I fitted the seal incorrectly.. .I went for a new Mcylinder from Kelvedon; easy bleed, no problems since...

If I ever get tempted to rebuild a classic master or slave cylinder, I would have it bored and sleeved in stainless: the firm 'Past Parts' did an excellent job on my 1967 Volvo Amazon.
Tony

[SENC]

Assuming you're bleeding via brake pedal pumping...

I think the pedal pumping action agitates and introduces tiny air bubbles in the circuit - which, while mixed, has a negligible impact and so you get a firm pedal - but once done and it stabilizes you end up with one or more large air pockets that are compressible and can't escape. My theory may be wrong, but I've had success resolving similar problems by holding the brake pedal down overnight (2x4 between pedal and seat).

[seniorchristo]

I've been using the mighty vac system for years. It's a simple, one man operation.

https://www.amazon.com/Mityvac-MV8000-P ... 131&sr=8-1

[prezoom]

I have been a using a Mityvac for more years than I can remember. That, coupled with SpeedBleeders work well together. Automatically convert any new old car to SpeedBleeders as soon as it hits the garage. As far as sleeving master and slave cylinders, I do it myself. Single cylinders are the easiest, with dual port cylinders being a bit of a pain. All started when I purchased a new slave, and found it had more inclusions in the casting than the old one had gouges and pitting. A bit irritating at the time. Wound up sleeving both.