Brake bleeding question

Started by Willie_B, February 19, 2022, 12:38:17 PM

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Willie_B

The woody I am working on has a newer brake system. A purple band dual master and something on the firewall. I have bled the system twice and get no bubbles but I still do not have a pedal. I am used to single line system so this one is new for me. While I am reading up on it all I figured I would ask here. Any tips or tricks?

MPlayle

I have heard that the "tandem" master cylinders need "bench bled" if they are new (never had fluid run through them before) to ensure the sections are pushing fluid out properly.

The last similar system I bled (on the Red 1991 Mini I sold back in October), I had to use a vacuum bleeder to be sure I was getting all the air out.  The "pump-the-pedal" method just did not quite work.  I also worked starting with the wheel furthest from the master to the wheel closest.  On a RHD car that would be: a) left rear, b) right rear, c) left front, d) right front.


Willie_B

From the reading so far it look like the brake limiter valve on the firewall is installed upside-down. Also it has been plumbed with the wrong F/R lines going to the wrong side of that valve. Bet that would make for some excitement when braking. 

MPlayle


MiniDave

Does it fit the other way around?

I had trouble bleeding the brakes on Buzz, I found this procedure in a Haynes manual.....

Go to the left rear, open the bleeder, push down slowly and hold for count of three, let up slowly and wait 15 sec. Repeat three times, then do the same on the other side. Bleed fronts normally....
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

Jimini II

I had trouble with a my Moke and Clubman Estate.
I read that having the rear as high as possible helped along with bench bleeding the master a power bleeder, bleeding every connection, and my Son pumping the pedal I finally removed all the air.
The largest pocket of air on both cars was where the front to rear line connects to the proportioning block on the rear sub frame.

Willie_B

After talking to a local UK mechanic he suggested that being as the calipers were new to put a hose on the nipple, open it and then push the pistons back. I got a surprising amount of air bubbles then. I did that 3 times of each side. That got me a firm peddle, but it is only 1/2" off the floor. So sorta progress. The UK guy is coming over on Tuesday to lend a hand to try to get a more better peddle.

94touring

What's the spacer situation like under the master?

Willie_B

Not sure. I put one red gasket under the master & on top of the metal plate. Don't know if there is a foam seal under the metal plate.

94touring

Just thinking, your rear drums could be out of adjustment too.

tsumini

Just FYI rear brakes.
I  adjusted the adjusters one additional flat after slight drag and pretty much locked up. I backed them off one flat where it may have slight drag. Then I started the car and drove a vigorously about a mile turned around an vigorously accelerated. Slowed down to make a LH turn and felt car bogging a little. Quarter mile later turned in driveway and rears were locked up and hot. Let the car/brakes cool overnight. Rear brakes free no dragging. Took car out for a vigorous drive, brakes woirked very well, good pedal no drag or heat. Left them that way.

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