1941 Master Cylinder

[G Pennington]

Having brake problems with the '41.  Pedal goes about 2/3 of the way down and it takes a lot of effort to stop the car.  I can pump it one or two times and the pedal comes up, and the car stops nicely with normal effort.  Can't see any leaks; fluid level in master cylinder OK. 
Not sure, but I'm thinking I should replace or rebuild the master cylinder.  Can anybody recommend a good supplier or re-builder?   Want to avoid poor quality, ill-fitting parts like I've received in the past.  The braking system is not a place to go cheap.

[Bobby B]

Gary,
Hi. For Cylinder rebuilding, I've had great Luck with White Post in the past. That is of course, if you're not doing it yourself, and it doesn't require re-sleeving. I bought a Master for the '47 from Kanter, and knock wood, it's been fine for years.
                                                                                                                            Bobby

[Steve Passmore]

Being able to pump up the pressure and the peddle going too far down usually means air in the system and or the brakes need adjustment. Bleed and adjust before you condemn the master cylinder.

[Jay Friedman]

You haven't mentioned your wheel cylinders.  In addition to the suggestions from Bobby and Steve, I would take off the 4 brake drums, peel back both rubber covers on each wheel cylinder, and if fluid drips out that wheel cylinder needs rebuilding. 

Another possibility is that one of your 3 rubber hydraulic hoses is faulty.  The difficulty with these is that they can be deteriorated on the inside but look perfectly OK on the outside.  It's easiest to just replace all 3: two at the front wheels and 1 between the rear of the driver's side frame and the rear axle.

I also suggest that if you send your master cylinder to White Post, that besides rebuilding it you have them sleeve it (I forget if they use brass or stainless steel).  A good idea is to also have the wheel cylinders sleeved. 
If you are really ambitious replace all the original hydraulic lines with stainless steel lines. 

I've done all the above on my '49, and except for changing the lining every few years the brakes have been trouble free ever since.  Besides White Post, another place that does this sort of work is https://hagensautoparts.com/

[mr41cadillac]

ive had these symptoms before and its was plugged hoses. I would take em off and check and if plugged or partially plugged do    a complete brake job. I got my kits from napa.

[Scott Anderson CLC#26068]

You haven't mentioned your wheel cylinders.  In addition to the suggestions from Bobby and Steve, I would take off the 4 brake drums, peel back both rubber covers on each wheel cylinder, and if fluid drips out that wheel cylinder needs rebuilding. 

Another possibility is that one of your 3 rubber hydraulic hoses is faulty.  The difficulty with these is that they can be deteriorated on the inside but look perfectly OK on the outside.  It's easiest to just replace all 3: two at the front wheels and 1 between the rear of the driver's side frame and the rear axle.

I also suggest that if you send your master cylinder to White Post, that besides rebuilding it you have them sleeve it (I forget if they use brass or stainless steel).  A good idea is to also have the wheel cylinders sleeved. 
If you are really ambitious replace all the original hydraulic lines with stainless steel lines. 

I've done all the above on my '49, and except for changing the lining every few years the brakes have been trouble free ever since.  Besides White Post, another place that does this sort of work is https://hagensautoparts.com/

A consideration before sending master and / or wheel cylinders to White Post. You don't mention the type of brake fluid (DOT3/4 or 5 (silicone)) that you plan to run. I  do understand that WP has a great reputation for the rebuilding and resleeving. However, their work is emphatically not for DOT5 applications. At the time I discovered this it was clearly stated in their literature.

Although I haven't used them personally for this, fwiw Hagens is in my home state (Washington) and I've heard nothing but good things about them.

[G Pennington]

Bleed the brakes (using a pressure bleeder).  Good flow, no air bubbles from front wheel cylinder bleeder valves.  Just a dribble from the rears.  Inspected the rear brake lines & hose, no pinches or kinks.  Guess I'll have to unhook everything and figure out where the blockage is.
BTW, according to the PO, the car was restored in the 1990s.  The entire brake system, including the steel lines and hoses, LOOKS to have been replaced.  I bleed it with DOT-3 fluid, but can't be sure what was used when it was restored.

[Marcel75]

You are probably right, your mc is to be renewed.
You can test it that way: you stop the car, you maintain pressure on pedal and wait...if after 20-30 seconds the pedal starts to move downards slowly until it hits the floor, your mc is out (one cup lets the fluid coming backwards in the mc chamber, decreasing pressure in the brakes lines).
A hard pedal when pressing it rapidly is an additional symptom of mc problem.

[G Pennington]

Rear hose was stopped up.  Since the hydraulic system was contaminated, I am replacing all 3 hoses, the wheel cylinders, the master cylinder (White Post), cleaning out all fittings, and blowing out all steel lines.
Thanks to all for the suggestions.