Brake bleeding question on ‘56 T-bird

[zuburg]

I bled the Midland power booster first, then bled the right rear and left rear wheels. It seemed to work as expected. When bleeding the right front wheel, the brake pedal fell nearly to the floor when I opened the bleeder valve. After this happening go 6 or more times and draining an awful lot of fluid from the bleeder, I decided to research what could cause this.

Any ideas? Could it indicate a leak somewhere that I’m unaware of?

I loosened and retightened the fitting on the hard line from the M/C to the booster to try and eliminate a small leak. If I bleed the power booster again first, will I have to bleed the two rear wheels again?

Back to the parts store for more fluid I go.

[KULTULZ]

You have a SGL RSVR MC, it has been bench bled and the front wheel cylinders are good?

Did you try the LF CYL?



Wait a minute. The pedal is supposed to go to the floor and you repeat until no air comes out of the bleeder screw.

This is OEM four drum?

[paul2748]

I assume you have some one pushing down on the pedal while you are at the wheel. When you open the bleeder valve the pedal usually goes to the floor. That's when you close the valve and lift the pedal then press down again to check for additional air in the system.. When all you get is fluid, that wheel is done.


Didn't it do the same thing at the rear? Or do you have a dual master cylinder?



Don't lift the pedal until the valve is closed.

[zuburg]

I have a new single reservoir M/C and new wheel cylinders and a recent rebuild of the brake booster. It is OEM brake shoes. I bled the M/C on the firewall by attaching a hard line to the output fitting on the M/C and bent it up and into the M/C reservoir, and pumped the brake pedal. This sounded to me to be just like bench bleeding without the vice holding the M/C.

My wife was pressing the brake pedal for me. I didn’t open the valve until she pressed and held the pedal. I closed the valve before she let off the pedal. It wasn’t until I opened the right front valve that she was surprised how far the pedal went down. It might have gone down some on the rears but not as much as the right front as she didn’t react to it like she did with the front. I did not try the left front because I was worried something was wrong.

Also, the fluid that came out of the right front wheel cylinder was much darker than the two rears. I had already bled all the brakes a number of years ago (but only drove it out and in to the garage (brakes seemed OK then)) after replacing all the wheel cylinders, flex hoses and most of the hard lines. I’m bleeding again because I just installed a rebuilt power booster and M/C. Also have been fighting leaks with the fittings and line from the M/C and booster.

I understand that if I ensure the hose I connect to the bleeder valve is routed higher than the wheel cylinder before the catch bottle I can do this myself and press the pedal myself? Does it matter where the bottle is as long as the tube travels higher than the master cylinder on its way to the bottle?

[KULTULZ]

You can bleed a MC on the car only if the MC is completely level as to not possibly have residual air trapped in the cylinder. If there is residual air or if the MC runs dry while bleeding the system, you have to start all over.

She needs to pump the pedal say five times to achieve some type of pedal. She then holds firmly and you open the bleeder. Allow the pedal to go completely to the floor. Repeat until the fluid is clear and no bubbles. Go to the next wheel end and repeat. Make sure the MC is kept full at all times.

The 2nd method you are describing is one man bleed but I would go through the two person method as everything is new.

Here Is An Article Describing How To Go About A Manual Bleed -

https://www.caranddriver.com/feature...d-your-brakes/

[richard crow]

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when bleeding the brakes don,t let the pedal go to the floor. stop an inch or two before end of pedal travel

[KULTULZ]

Originally Posted by richard crow

when bleeding the brakes don,t let the pedal go to the floor. stop an inch or two before end of pedal travel

Correct, I overlooked that little detail -

Put a piece of 1x4 lumber or some other spacer under the pedal to prevent it from traveling too far and overextending the brake master cylinder when the brake system is opened and the line pressure is released. Refill the empty master cylinder reservoir with fresh fluid up to its maximum fill line and put the cover back on the reservoir. Fluid can squirt out of an open reservoir every time the pedal is released.

SOURCE - https://www.popularmechanics.com/car...-bleed-brakes/

This is one reason to make sure the MC is bled properly to begin the operation. Any residual air within the MC may not be removed with this limited stroke.

[5851a]

Do the baby birds use the power assist on all 4 wheels or just the front?

[KULTULZ]

Originally Posted by 5851a

Do the baby birds use the power assist on all 4 wheels or just the front?

All four on OEM drum brakes -

OEM MIDLAND BOOSTER of course ...

[5851a]

Ok Thanks, had just wondered if it did if that may account for difference.

[5851a]

Ok thanks.

[Daves55Sedan]

One of my favorite tool purchases of all time has been my MityVac. I use it for bleeding brakes, sucking gas out of the lawnmower gas tanks and several other uses.
It's easy to bleed brakes with a MityVac.
1) Make sure master cylinder is FULL of fluid at all times.
2) Begin at farthest wheel cylinder from the M/C. Connect the flexible clear plastic tube to the bleeder screw, then loosen the bleeder screw. Pump the MityVac pump handle and fill the Mityvac reservoir. Watch for air bubbles in the clear plastic tubing as you vacuum the fluid out of the line. When bubbles are gone, close bleeder screw and refill M/C.
3) Go to next furthest wheel cylinder and repeat, then the next, then the last, always re-filling the M/C.
4) Now with all the lines bled and bleeder screws closed you SHOULD have a tight brake pedal.

[KULTULZ]

The one thing that is troublesome with a vacuum bleeder is that when the bleeder screw is loosed, the threads (NPT) will allow air to be drawn past those threads into the cylinder. While most should be drawn out by the current of flow due to the vacuum, the resulting air bubbles may make it difficult to determine whether friendly or entering via the threads making it hard to determine if all air has been removed.

Same problem with one man bleed. You partially fill a container with fluid and hope if fluid is ingested back into the system when the pedal is released, that fluid will be clean. There also has to be a one way valve used.

I kept reading about speed bleeders and poo-pooed the idea. Bit I recently went thru a TAURUS with ABS and performing any service or flush, the replacement fluid has to be clean and of the correct viscosity. I bought a set and they worked like a charm.

I didn't leave them on the car but put them in my box for future use. If you have a dedicated car and care about keeping the fluid fresh, this is the best option (IMO) other that buying an expensive pressure flush system.

[Gene F]

I have a vac too. It works nice, but a good partner to work the brake pedal seems to bleed them just a bit firmer. Maybe I'm just imagining that...