brakes

coolcoupe

coolcoupe

Well-known member
I have a 1947 car which I replaced the m/c and all the brake lines. Now I can't
get a good pedal of brakes. I've benched bled the m/c and bled all the lines 4 times. I did get a good pedal once (smile) then 1 hr later it was 1/4 pedal. There are fluid leaks anywhere. Any ideas ?
 
You said there are leaks. Did you mean there aren’t leaks?

What method do you use to bleed the brakes? You installed all original equipment style parts?
 
It looks like coolcoupe is saying there are no fluid leaks.
First order of business, your brakes need to be adjusted properly. If that is not an issue, and there are no leaks, then you must still have air in the system.
Air bubbles, over time, will travel to the highest point in the system.
You may want to try a little trick that once worked for me, after installing a new mc.
Remove the cap on the mc. Fill reservoir. With a bucket placed under the mc, SLOWLY
depress the pedal and watch for escaping air bubbles. Repete until no more bubbles, while replacing any spilled fluid and keeping the reservoir full. The pedal should harden up. If so, replace the cap and off you go. The full reservoir should keep any air from entering the system while the cap is off.
I am no brake expert, but this trick is easy and just may work for you.
 
Sorry, I did mean there was no leaks anywhere. I gave up on it for the weekend
but will get back to it Monday morning. I will try what you mentioned first and see what happens. Thanks for replies.
 
I did use the right m/c. I used the 2 person bleeding system as it worked every other time. I flaired all the lines and no leaks
 
If the car had well adjusted shoes before you should be ok there. But if it never was driven with those shoes, I’d start with those before you work on the fluid.

Then, it sounds like you are bleeding them correctly. But maybe give it another shot. Starting at the farthest corner, and making sure to never let the master run dry.

If still no luck, pick up some Speed Bleeders. They will help eliminate one point of air into the system.

If that still fails, maybe take the master apart and see if there is a nick on the inner cups, or gouge in the cylinder.
 
Normaly bleeding the air from an hydraulic system is straight forward and should not be that difficult, but it could be that ...........
1-The new seals /parts in the master cilinder are not the correct type or fitted incorrectly
2- On some cars the brake pedal travel has an effect on the performance of the brakes
3- Dirt may have entered the system
4- i'm sure there are more pitfalls


If nothing works at home, you can always try a professional garage whom are using a vacuum unit to change /replace the brake fluid, this is very effective
 
Humm,
Good thread. John Kelley is having very similar problems on his 46 4 door (Howard).
I will mention this thread to him. But he has probably already seen it.
Regards,
Chris
 
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