Methods: best way to rebuild and bleed entire brake system

[TxDon]

I did a full brake system rebuild on my 66 Monaco wagon including switching to a dual master cylinder, if you have the time look at my long thread:

66 Monaco Wagon Preservation

 

[edbods]

Has anyone had a failure in a dual master cylinder system?

When it happened to me the pedal goes to the floor and it a crap your pants time anyway if over 20 mph. Still need to use the park brake and steer it to safety.

It's not that much better and it's a change the underwear time afterwards. But yes it's not zero brakes.

Luckily for me the only time it happened was when I bled the brakes and I pushed the pedal a bit too far - the unit had been on the car since at least 1989, so the internal piston seal must've picked up some crud or corrosion. Set me back 100 bucks to resleeve the bore and another 100 or so to find an OEM rebuild kit.

 

[fury fan]

Has anyone had a failure in a dual master cylinder system?

When it happened to me the pedal goes to the floor and it a crap your pants time anyway if over 20 mph. Still need to use the park brake and steer it to safety.

It's not that much better and it's a change the underwear time afterwards. But yes it's not zero brakes.

First time, the pedal went right to the floor and there's really no driving it home because brakes are minimal at best. The second time, a front hose burst during a panic stop on the top of an on-ramp and I hit the woman's Plymouth Horizon with my NYB that had stopped dead in front of me.

IMHO, the dual brake system is not what people think it is.

Agreed, we praise a dual-circuit MC too much.
30 years ago I had a front brake hose blow on me in rush hour traffic and cause a 4-car pileup. (1980 model car)
When you lose the fronts in a hard stop, the loss of braking causes the front of the car to rise up to normal and it feels like you floored the accelerator.

Would I convert to dual-circuit? Absolutely.
Would I expect it to be a guarantee of safe braking? Absolutely not.
A dual-circuit MC's main benefit is if you lose the rear brakes.

Luckily for me the only time it happened was when I bled the brakes and I pushed the pedal a bit too far - the unit had been on the car since at least 1989, so the internal piston seal must've picked up some crud or corrosion. Set me back 100 bucks to resleeve the bore and another 100 or so to find an OEM rebuild kit.

I was thinking this also. Putting full-stroke on a used MC while bleeding wheels causes the piston to travel into uncharted bore area.
I lost a MC due to that years ago, so I am careful to not do that anymore.

 

[Big_John]

I was thinking this also. Putting full-stroke on a used MC while bleeding wheels causes the piston to travel into uncharted bore area.
I lost a MC due to that years ago, so I am careful to not do that anymore.

Been there... Done that.

I put a 2x4 under the brake pedal to try to stop the full stroke with some success.