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Old 07-13-2011, 12:42 AM   #1
tttuba
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brake light switch

Once again I come to the people that know.....I have a 47 that the previous owner put power brakes on. I am changing the wire harness since the prior owner also did a horrible job with the wiring....all the same color. So my question... is there a brake light switch on the vehicle somewhere or could it be this thing I found in the middle of the brake line which has 2 wires coming off of it? Kind of looks like this might be a switch activated by pressure in the line. But I have never seen anything like that before so I am confused.
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Old 07-13-2011, 01:23 AM   #2
mr48chev
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Re: brake light switch

That should be it, a 'Ford style brake light switch.

Probably quite similar to this one http://www.rockauto.com/catalog/rafr...185671-3146202

I have one on the 48 and usually have had to replace it about every other year. It isn't very expensive and is easy to find though.
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Old 07-13-2011, 01:30 AM   #3
tttuba
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Re: brake light switch

Kind of looks like that but when you replace it do you have to bleed the brakes?
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Old 07-13-2011, 09:44 AM   #4
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Re: brake light switch

It's a good idea. But if the truck has been sitting for any length of time you will probably need to bleed the brakes anyhow. Usually if you have the new switch ready to go in you don't loose a lot of fluid or get much air in the system.

Unscrew the old one, hold your finger over the hole, screw in the new one.

You should be able to cross the Standard SLS27 number at any parts house you go to. By clicking on the number you can see the applications and it fits a lot of different vehicles including some Jeep models up through 1973.

The thread should be 1/8" pipe but there may be a different size unit out there that I don't know about. NAPA link https://www.napaonline.com/Catalog/C...213430960&An=0

Last edited by mr48chev; 07-13-2011 at 09:51 AM.
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Old 07-13-2011, 04:59 PM   #5
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Re: brake light switch

Quote:
Originally Posted by mr48chev View Post
That should be it, a 'Ford style brake light I have one on the 48 and usually have had to replace it about every other year. It isn't very expensive and is easy to find though.
In the past I have used these switches but I found out by using a relay to switch the pressure switch lasted until I sold the truck (3 Years).

I have also used a motorcycle H.D. switch which is the same size and uses 12VDC also
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53 TuTone Extended Cab 350 4-Spd 3:08 (SOLD)
53 Chevy Moldy pearl green ZZ-4 4L60E 9" 3:25
55 GMC 1st Black Mll (ZZ4) ZZ6 TKO 600 5 sp 3:73
62 Solidaxle Corvette Roman Red (327
340hp 4spd 3:36) C4 & C5 suspension tube chassis
LS 3 4L70E
65 Corvette Coupe 327 350hp 4spd 4:11
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Old 07-13-2011, 05:08 PM   #6
mr48chev
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Re: brake light switch

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Originally Posted by solidaxel View Post
In the past I have used these switches but I found out by using a relay to switch the pressure switch lasted until I sold the truck (3 Years).

I have also used a motorcycle H.D. switch which is the same size and uses 12VDC also
I never thought about using a relay on the stop lights.

I have them on the headlights of the 71 and they will be on the 48 when I do the rewiring.
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Old 07-13-2011, 05:20 PM   #7
solidaxel
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Re: brake light switch

Quote:
Originally Posted by tttuba View Post
Kind of looks like that but when you replace it do you have to bleed the brakes?
Depends on how long it takes to screw in the new switch and how much fluid you lose when you remove the old switch.
Is the switch on the rear brake line or at the master cylinder?
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53 TuTone Extended Cab 350 4-Spd 3:08 (SOLD)
53 Chevy Moldy pearl green ZZ-4 4L60E 9" 3:25
55 GMC 1st Black Mll (ZZ4) ZZ6 TKO 600 5 sp 3:73
62 Solidaxle Corvette Roman Red (327
340hp 4spd 3:36) C4 & C5 suspension tube chassis
LS 3 4L70E
65 Corvette Coupe 327 350hp 4spd 4:11
78 Black Silverado SWB (350/350) 5.3 & 4L60E 3:42
2000 S-Type 3.0 (wife cruiser)
2003 GMC SCSB 5.3 4L60E 3:42
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Old 07-13-2011, 08:47 PM   #8
tttuba
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Re: brake light switch

It is in the rear brake line on the truck frame rail
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Old 07-14-2011, 01:11 AM   #9
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Re: brake light switch

Be quick and don't cross thread it, you will be O K !!
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53 TuTone Extended Cab 350 4-Spd 3:08 (SOLD)
53 Chevy Moldy pearl green ZZ-4 4L60E 9" 3:25
55 GMC 1st Black Mll (ZZ4) ZZ6 TKO 600 5 sp 3:73
62 Solidaxle Corvette Roman Red (327
340hp 4spd 3:36) C4 & C5 suspension tube chassis
LS 3 4L70E
65 Corvette Coupe 327 350hp 4spd 4:11
78 Black Silverado SWB (350/350) 5.3 & 4L60E 3:42
2000 S-Type 3.0 (wife cruiser)
2003 GMC SCSB 5.3 4L60E 3:42
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