Go Back   The Ford Barn > General Discussion > Early V8 (1932-53)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 07-01-2020, 03:11 PM   #1
mcgarrett
Member
 
Join Date: Dec 2013
Location: Palmer, Texas
Posts: 65
Default Installing brake switch on 1940 master cylinder

I had a hard time bleeding my master cylinder and and getting all the air out but finally have solid pedal, but have now discovered that my brake light switch is not working . I had silicone fluid in the system previously and have switched back to conventional fluid. I have since learned that silicone isn't too friendly to hydraulic brake switches and I assume that's why my quit working.

Here is my question:
Is it possible to replace it WITHOUT having to bleed again?? I'm trying to avoid the hassle of bleeding again. Would appreciate any and all feedback.
mcgarrett is offline   Reply With Quote
Old 07-01-2020, 05:10 PM   #2
drolston
Senior Member
 
drolston's Avatar
 
Join Date: Jun 2014
Location: Williamsburg, VA
Posts: 1,082
Default Re: Installing brake switch on 1940 master cylinder

It can be done. Put a helper in the car with a hand on the brake pedal. Remove the bad switch and quickly start the new switch about two threads. Have the helper press the brake pedal lightly by hand until you see some leakage past your loose threads. Keep the light pressure on until you have the new switch down tight. Should be fine after you get the brake fluid off of your hand.
drolston is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 07-01-2020, 05:14 PM   #3
mcgarrett
Member
 
Join Date: Dec 2013
Location: Palmer, Texas
Posts: 65
Default Re: Installing brake switch on 1940 master cylinder

I thought that might work but wanted to get the expertise of others before I tried it. Thanks for your tip!
mcgarrett is offline   Reply With Quote
Old 07-01-2020, 06:29 PM   #4
51woodie
Senior Member
 
51woodie's Avatar
 
Join Date: Apr 2018
Location: Chelmsford, ON Canada
Posts: 305
Default Re: Installing brake switch on 1940 master cylinder

I had a problem with the brake switch on my '46, and replaced it with a switch from Harley Davidson, P/N 72023-51E. I cost me C$30.00 with tax, probably $20.00 US. Works well for me.
51woodie is offline   Reply With Quote
Old 07-01-2020, 06:35 PM   #5
51504bat
Senior Member
 
51504bat's Avatar
 
Join Date: Sep 2013
Location: SoCal-Redlands
Posts: 1,606
Default Re: Installing brake switch on 1940 master cylinder

Changed the one on my '39 p/u without having to bleed the system afterwards. Unscrewed the defective one and screwed in the new one. Easy peasy.
__________________
Making the simple complicated for over 30 years.
51504bat is offline   Reply With Quote
Old 07-01-2020, 06:38 PM   #6
Kube
Senior Member
 
Kube's Avatar
 
Join Date: May 2010
Location: Wisconsin, USA
Posts: 6,339
Default Re: Installing brake switch on 1940 master cylinder

Sponsored Links (Register now to hide all advertisements)
There's no need to bleed nor have the pedal pushed slowly while replacing this switch. Gravity will allow a bit of fluid to escape while you're doing the R&R.
__________________
"I can explain it for you. However, I can't understand it for you".
Kube is offline   Reply With Quote
Old 07-01-2020, 07:09 PM   #7
russcc
Senior Member
 
Join Date: May 2010
Posts: 2,407
Default Re: Installing brake switch on 1940 master cylinder

Any of the hydraulic switches immune to DOT 5, or do you have to use a mechanical ?Thank you Fordbarners
russcc is offline   Reply With Quote
Old 07-01-2020, 09:29 PM   #8
mcgarrett
Member
 
Join Date: Dec 2013
Location: Palmer, Texas
Posts: 65
Default Re: Installing brake switch on 1940 master cylinder

Thanks to all respondents - I think I'll try swapping out the switch without using the buddy system; the theory seems sound.
mcgarrett is offline   Reply With Quote
Old 07-01-2020, 10:49 PM   #9
FlatheadTed
Senior Member
 
FlatheadTed's Avatar
 
Join Date: May 2010
Location: Auckland
Posts: 4,283
Send a message via AIM to FlatheadTed
Default Re: Installing brake switch on 1940 master cylinder

X 2 for no buddy system; but check the quality of the threads first ,
__________________
http://www.flatheadted.com
FlatheadTed is offline   Reply With Quote
Old 07-02-2020, 04:37 AM   #10
flatheadmurre
Senior Member
 
flatheadmurre's Avatar
 
Join Date: Apr 2015
Location: Sweden
Posts: 3,045
Default Re: Installing brake switch on 1940 master cylinder

Works fine just being quick.
And any air bubble will find its way up into the reservoir.
flatheadmurre is offline   Reply With Quote
Old 07-02-2020, 06:30 AM   #11
corvette8n
Senior Member
 
corvette8n's Avatar
 
Join Date: Jul 2010
Location: 36 miles north of Albany NY
Posts: 2,020
Default Re: Installing brake switch on 1940 master cylinder

Swapped mine on my '41, I don't think even one drop of fluid came out, took 5 minutes.
corvette8n is offline   Reply With Quote
Old 07-02-2020, 03:22 PM   #12
JSeery
Senior Member
 
JSeery's Avatar
 
Join Date: Nov 2012
Location: Wichita KS
Posts: 15,121
Default Re: Installing brake switch on 1940 master cylinder

Quote:
Originally Posted by russcc View Post
Any of the hydraulic switches immune to DOT 5, or do you have to use a mechanical ?Thank you Fordbarners
At one time Harleys used DOT5 so that switch was the recommended one. But some people seem to have issues with them as well. See post #4.
JSeery is offline   Reply With Quote
Old 07-03-2020, 09:23 PM   #13
mcgarrett
Member
 
Join Date: Dec 2013
Location: Palmer, Texas
Posts: 65
Default Re: Installing brake switch on 1940 master cylinder

A big thank you to all for the helpful tips. Just installed the brake light switch without a helper and I'm pleased to say I now have brake lights again!!
There's vast knowledge here at Barn!
mcgarrett is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 06:24 AM.