1941 Brake Bleeding Advice

[Morgan Murphy, No. 17409]

Well, Ive bought the items needed for a brake rebuild.  Unfortunately, most of them have not arrived, including the shop manual for a 41 (ordered that from AllCads over a week ago, and it still hasnt even been sent).

Today, I wanted to bleed the brakes, just to get the car driveable for a little while until the rest of the wheel cylinders, etc. come in the mail.  Any advice about how to bleed them (remembering, of course, that I have no shop manual yet)

Thanks!

[Mike #19861]

 Bleeding brakes is a pretty common procedure that is essentially the same for all cars.

 Fill the master cylinder with fresh clean fluid from a new bottle. Then grab a volunteer. Have him sit in the car to pump the brakes.

 Starting at the farthest point from the master cylinder, which would be the right rear wheel, have him pump the brakes several times, then hold pressure on the pedal. At that point open the bleeder screw until no more fluid comes out. If there is air in the system, it will be expelled along with the fluid. Close the bleeder, and have your assistant pump the brakes again. Repeat this process until nice clean fluid with no air comes out. Then do it one more time.

 Make sure that through this process the master cylinder is kept topped up and the lid is on. If the reservoir runs out, then the whole process must be repeated.

 Then once you are sure there is no more air in the rt rr cylinder, move to the left rear, then the right front, then the left front.

 Also, be sure the brakes are properly adjusted before you start the process. Out of adjustment brakes can cause a longer pedal stroke.

  Mike

[Morgan Murphy, No. 17409]

Mike:

Thank you for the tips.  I got out there under the car this afternoon and didnt have too much trouble, other than losing some skin on my knuckles and discovering that the front bleeder valve nipples were missing.  The rear was a piece of cake!

Another question:  when I called to get a new master cylinder, they asked me at Kanter if it was a power unit.  Did some 41s have a power option on the brakes?  I see what looks to be wiring and a vacuum unit on the front of the current master cylinder, although it seems to be cut off.

Morgan

[Mike #19861]

 I am by no means an expert on this, but vacuum assisted brakes were available on cars as early as the early 30s, when most were still mechanical systems. This may have been carried over as late as 1941.

 The wires that were cut may be for the brake lights. Early brake light systems were activated by pressure in the system instead of pedal activation like all new systems are. Ford used this system as late as the 60s, so if you want to restore this, a switch from that era of Ford may do the trick if the original is not available.

 Mike

[JIM CLC # 15000]

11-26-05
Morgen, Two thing to consider. First. Once you have bled the brake system, you may have some frozen wheel cylinders. To test for frozen cylinder(s), in a safe area, apply the brakes rear-hard, if only one wheel locks-up, the others may be wheel cylinder(s) may be frozen. Tip: you can bleed the system with frozen wheel cylinders. Second thing to consider is the hydraulic brake light switch. There was an article in the SS whereby you can connect a horn relay in the brake-light electric circuit that will prolong the life of the BL switch.
(to is something I plan to do).
Good luck, Jim

[Bob Schuman, CLC#254]

Morgan and Jim:
The article on the stoplight switch relay, which also explained that silicone brake fluid is not the cause of switch failures, was in the May 2003 Self-Starter. If you need a copy, e-mail me and I will send a copy as an e-mail attachment.
Bob Schuman

[John Washburn]

Bob,

Was reading an article somewhere and they were talking about manufacturers who use silicone brake fluid on their products. One of these is Harley Davidson. The article also stated that they use pressure switches and that they will fit the early 36-48 (??) Cadillac and LaSalle. I have not checked this out yet, but plan to take one of the brake switches and see if they have similar ones.

Im to lazy to pull the SS, so hope this was not you. I think it was in a recent article in Skinned Knuckles (Nov 2005).

John Washburn
CLC #1067