bleeding brakes

[WillR]

according to the shop Manuel you start with the shortest line. After disconnecting the wires to the master cylinder and unscrewing the nut all i get when bleeding is air and the occasional bit of fluid. I just figured it would take more time but i must be missing something! has this happened to any one? any ideas?

 

[tony barnhill]

Where are you getting the air? at the MC?

 

[WillR]

The air is still coming from the calipers, not clear fluid. Pump the brake to the floor, open the bleed screw, close the bleed screw, and let the pedal return...dozens and dozens of times, still mostly air, not clear fluid!

Does the bolt (that holds the pressure equalizer?) on the MC need to be open?

 

[Guest]

Try bleeding the M/C first and then the remainder of the system... or get a vacuum bleeder and pull the fluid through the system. Another option is to open all the bleeder screws at the same time, fill the reservoir all the way to the top, grab a drink and sit down and wait patiently for gravity to do the job... but you still must follow up with the pumping at the pedal. er, you ARE holding the pedal down whilst opening the bleeder screw, right!?

 

[gblawson]

...and I was always told to bleed the furthest first.... RR,LR,RF,LF? (MGTD)

If you put a hose from the bleeder screw down into a full 'large' container of fluid, you can bleed them alone...just push the pedal to the floor again and again until no air goes down into the container (a clear hose helps).

 

[WA1KWA]

I always did the furthest first, also.

After the pedal hits the floor, close the bleed nipple, then, pump the brake pedal a good 8 - 12 times before starting all over again.

Definetly a two person job.

Colin

 

[mgb4tim]

I've done the furthest first, too. Two people makes it easier, and is more fun drinking beer after with a friend.

 

[CraigFL]

I never had any luck with (the) bleeding brakes until I made a pressure bleeder. Fitting in cap from old MC. Pressure bottle full of brake fluid with tubing to MC fitting. Air line from regulator to pressure bottle. Turn pressure to 5-7psi, open bleeder nipple and wait for clean,clear fluid. Do other three. Top off MC and drive--- Works every time!

 

[WillR]

i set up a vacuum to the brake bleeder i bought. I left it going as i tried to get a few other things done. Nothing but air. i bleed the front two with just the bleeder but nothings coming out of the drums. the pressure bleeder sounds like a good idea. I have until 330 to move my car. As it is/has been blocking in my dads healy all summer. on another topic any ideas how to tighten a stubborn tie rod end? as soon as i get the nut on the whole thing turns with it.

 

[WillR]

ok tie rods are in. brakes still in need of some love.

 

[RonMacPherson]

helpful hint: when using vacuum, remove the nipples and wrap a strand of teflon tape sealer around the threads of the nipple then put them back in the caliper.

This cuts down on any air flow past the threads of the bleeder when you are trying to direct your suction from the hydraulic system.

 

[Dave Richards]

helpful hint: when using vacuum, remove the nipples and wrap a strand of teflon tape sealer around the threads of the nipple then put them back in the caliper.

This cuts down on any air flow past the threads of the bleeder when you are trying to direct your suction from the hydraulic system.

Teflon tape already done.

Air, not fluid will come from one connection, or the other, at the MC, but not both.

Used a Mity vac, to no avail on the rear brakes.

I'm <span style="text-decoration: underline">assuming</span> there is air trapped in the MC and that pressure regulating valve is somehow the culprit. We will build and use a pressure bleeder Monday. The car is off the jack stands and Healey is liberated, YEA! (See post in Healey forum, if you're up to it.)

 

[jlaird]

Have you considered that the line is pluged up?

 

[Dave Richards]

Have you considered that the line is pluged up?

No, hadn't considered that. How would you check that? Compressed air, maybe?

 

[gblawson]

You are removing/loosening only one wheel cylinder bleeder nipple at a time?

 

[WillR]

usually only one. i opened two to let gravity do something. didint work. pressure bleeder is set up with a gauge. I get up to 20 lbs of pressure open the back nipple and all i get is air. the fluid level in the res is not moving but i pump until my arms get tired. am i in line for a new mc?

 

[jlaird]

To check, disconnect both ends of the line and blow through it for starters.

Now when bleeding, and I must disagree whith what you said up front. You always bleed the longest line first and work down. Usually rear right, rear left, front left and front right.

Wait, nothing from the master cylinder only air through to the brake cylinders, front and rear? Has to be the master cylinder in that case. I think I would disassemble the master cylinder and get the crud out for starters and go from there. Something is blocking the fluid or...........time for a tear down.

 

[Dave Richards]

Latest update:

I agree that the longest run should be done first (as I do on the Healey), but I will also defend my ability to read: from the Haynes manual (66010) MGB 1962 - 1980 Chapter 9, section 7 (page 149)"Bleeding the hydraulic system (Pressure Differential Warning Actuator in circuit)" Step 2 <span style="font-style: italic">"Bleed the front caliper nearest the master cylinder FIRST, followed by the other front caliper and then the rear brakes."</span>

Regardless: When the master cylinder has been pressurized to 10-15 psi, the front brakes can be bled, but the rear brakes only hiss air (I would assume no blockages from the continuous sound of air from the bleed nipples. This is what baffles me, how can the air bypass the fluid in the reservoir???

I'm guessing it has something to do with this pressure differential valve. We're going to have to take the thing apart and probably end up buying a rebuilt one. But does this make sense to anyone, has anyone had similar problems?

 

[Dave Richards]

NEW master cylinder, homemade pressure bleeder, 2 guys, 15 minutes, done!