Hydraulic brake adjustments.
 

Hydraulic brake adjustments.
I have 1940 Ford hydraulic brakes on my 1931 Model A Ford.
All cylinders are brand new with new rubber. And New Brake shoes.
This system has about 500 miles on it.

I recently had to change the brake light switch on the master cylinder.
My son and I bled the system after installing the brake light switch.

The brakes do not stop the car as well as it did before bleeding the system.

How do I tell if the problem is air in the system or too much brake shoe clearance ?

Re: Hydraulic brake adjustments.
 

Good luck with Lockheed brakes. I gave up on them and use repro bendix brakes. Way easier to adjust. Your problem is probably too much air and brake shoe clearance. If you arch the shoes to new drums you have a chance to make 40 brakes work. Much easier is using DOT 3 brake fluid. I gave up on DOT 5 as it is much more difficult to bleed and get a firm pedal. If you send your Model A mechanical brakes off and get them restored by Synders for approx $2,000 a set then they can stop as well as hydraulics. I did that twice for Model A. https://mrtexasmodela.weebly.com/4648brakes.html

https://sites.google.com/site/mrtexa...ydraulicbrakes

Re: Hydraulic brake adjustments.
 

Hi,


So since this started with the recent brake bleeding, you probably have your shoes adjusted properly.



Did you bleed the brakes starting from the furthest brake form the master cylinder, usually right rear for LHD, working into the closest? Does the brake pedal feel soft and spongy now? This will indicate air is still in the system. Are all the bleeders tight with no evidence of leakage?


I have also made a practise of putting pressure on the brake pedal overnight by wedging a piece of wood between the seat and the pedal to keep a little constant pressure on the system. It helps to get the last of the air bubbles to migrate back to and get released at the master cylinder.


I also prefer DOT 3 and 4 brake fluid. 4 is what I use after bad experience with DOT 5 but that's another discussion!


Glenn

Re: Hydraulic brake adjustments.
 

The problem started with the change of the brake light switch and bleeding the system, so it stands to reason that there is still some air in the lines. I would try bleeding it again.

Re: Hydraulic brake adjustments.
 

I know this is of little importance but, when I changed the brake light switch on my stock 40, I didn't have to bleed or adjust the brakes. Wonder why you didn't have the same experience. In any case, you will prevail.

Re: Hydraulic brake adjustments.
 

Me too & I’ve been using dot 5 in my 40 for the last 23 years without any issues.

Re: Hydraulic brake adjustments.
 

I consulted the hydraulics section of Ford V8 Service Bulletins 1938-1940 Complete on it's pg 459 and it suggests that the free play in the pedal if made zero results in blocking the bypass port so fluid cannot get back into the reservoir. It also says this condition could come from the rubber swelling due to improper fluid mineral oil instead of alcohol or M3833 fluid in cleaning the parts. Did I spend wisely with Amazon to obtain this book or is it too far from the common man?