Can 1967 Brake Warning Switch be installed without bracket 3910797? (UPC 5-B1)

[Scott S.]

1967
UPC 5-B1
Item 1 (3910797 Bracket)

I cannot find the bracket (GM 3910797) for mounting the Brake Warning Switch Asm., and the best picture I have of the area before taking the car apart doesn't show a good angle.

Could the brake warning switch have been mounted to the brake master cylinder just by suspending it from the attaching brake lines, or would it have required the bracket in order to be operational all these years?

Can anyone tell from this picture whether it was there or whether it was missing? I'm trying to figure out whether it has been missing for 30+ years, or whether I've misplaced it. I do have the Bolt that attaches the Bracket to the Brake Warning Switch.

For reference, Bolt looks like black phosphate, measured 5/16-18 x 5/8", indented hex, flat tip, Gr5, "E" headmark w/attached flat washer (UPC 5-B1, Item 3, 9419370 Screw Asm).

[Richard M.]

Re: Can 1967 Brake Warning Switch be installed without bracket 3910797? (UPC 5-B1)

Scott, The bracket is available. See this: Zip part DB-497. They have it listed a Proportioning Valve Bracket. It isn't. It should be listed as a Brake Warning Switch Bracket. Unless for J56 HD brakes then it uses a Proportioning Valve.

It would be wise to add the bracket to reduce vibration of the lines.

Rich
p.s. what is that line on the right, and where is it going to?

[Richard M.]

Re: Can 1967 Brake Warning Switch be installed without bracket 3910797? (UPC 5-B1)

....is that a hydraulically activated brake light switch? I can't see where it goes below in the photo but could it be Tee'd into the brake block on the frame?

sorry I cannot stay up anymore....going to sleep. I'll check in later.

Rich

[Scott S.]

Re: Can 1967 Brake Warning Switch be installed without bracket 3910797? (UPC 5-B1)

Scott, The bracket is available. See this: Zip part DB-497. They have it listed a Proportioning Valve Bracket. It isn't. It should be listed as a Brake Warning Switch Bracket. Unless for J56 HD brakes then it uses a Proportioning Valve.

It would be wise to add the bracket to reduce vibration of the lines.

Rich
p.s. what is that line on the right, and where is it going to?

Hi Rich,

Thanks for the link, I will certainly replace it if I have to, I just don't know whether I have misplaced the original or if it's been gone for decades.

I don't know what the line on the right is for, or where it goes (no pictures showing where it terminated). '67 Corvette school is in session for me every day, but I haven't gotten to that part yet... I'll cross that bridge when I get to it.

[Stephen L.]

Re: Can 1967 Brake Warning Switch be installed without bracket 3910797? (UPC 5-B1)

Scott, your M/C and brake switch look like a unique setup, with the "extra" Hydraulic device located next to the M/C.

Could this be a part of J56 brakes???

Refer to AIM UPC J56 A1.

Here is a photo of the standard brake setup on my BB 67 non-power brakes.

The flat bracket located on your firewall appears to be original which is different on my firewall.

[Scott S.]

Re: Can 1967 Brake Warning Switch be installed without bracket 3910797? (UPC 5-B1)

Scott, your M/C and brake switch look like a unique setup, with the "extra" Hydraulic device located next to the M/C.

Could this be a part of J56 brakes???

Refer to AIM UPC J56 A1.

Here is a photo of the standard brake setup on my BB 67 non-power brakes.

The flat bracket located on your firewall appears to be original which is different on my firewall.

Excellent point, another mystery

I looked at the J56 section of the AIM, but I don't know enough about what I'm seeing in the picture to determine if it's a part of a J56 set-up (probably not). I dug through my photos for better shots of the area, but only one still shows that piece, the rest are just better pictures of that firewall section.

What do you think?

I'll get pictures of the (now missing) piece in picture #1 below the next time I'm over to see the car. It's just sitting quietly while I research what I need to do next.

[Scott S.]

Re: Can 1967 Brake Warning Switch be installed without bracket 3910797? (UPC 5-B1)

I tried to blow up the picture of the tag, it looks like it says "Spliced into _ _ _ _ _ _ _ _ harness from inside car. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ clutch rod."

I didn't write it, that particular part was disassembled sometime in May (or earlier) of 2009, and I wasn't there at the time. I will find out

[Stephen L.]

Re: Can 1967 Brake Warning Switch be installed without bracket 3910797? (UPC 5-B1)

In my earlier post I thought the bracket behind the M/C was different than the "standard". After looking at your bare firewall photos that bracket isn't there... upon closer inspection of your original photo that "curved" bracket is probably a black wire. Now, with the card note you posted I have another thought. If that open hydraulic line went to the front brakes could this be a device to "lock" the front brakes for drag racing??? with a release switch inside the car..... an aftermarket addition which resulted in repiping the brake lines and removing the correct bracket for the switch.

BTW.. that switch was installed to let the driver know that he had a fluid/pressure loss in the braking system by turning on the brake indicator on the instrument panel which is shared with the e-brake. That is why the flashing bulb was eliminated in favor of a steady light on this application in 1967.

[Scott S.]

Re: Can 1967 Brake Warning Switch be installed without bracket 3910797? (UPC 5-B1)

In my earlier post I thought the bracket behind the M/C was different than the "standard". After looking at your bare firewall photos that bracket isn't there... upon closer inspection of your original photo that "curved" bracket is probably a black wire. Now, with the card note you posted I have another thought. If that open hydraulic line went to the front brakes could this be a device to "lock" the front brakes for drag racing??? with a release switch inside the car..... an aftermarket addition which resulted in repiping the brake lines and removing the correct bracket for the switch.

BTW.. that switch was installed to let the driver know that he had a fluid/pressure loss in the braking system by turning on the brake indicator on the instrument panel which is shared with the e-brake. That is why the flashing bulb was eliminated in favor of a steady light on this application in 1967.

Good call Stephen, right on the money. The previous owner (1972-1976) drag-raced the car for two summers ('75 & '76). He removed the engine-bay A/C parts to save weight and horsepower (included the original A/C parts with the car in boxes) and installed a Hurst Line-Lock, the switch had been under the dash cluster all these years.

You will also see a switch on the inner fender, facing the driver, in picture #3 from Post 6. It had a toggle switch that went through to the wheel side of the inner fender, near the top and just to the right of the battery access panel. I don't know what that switch was for yet, but I suspect it was part of an alarm system the previous owner installed. There was another toggle switch inside the cabin, on the back side of the divider between the front seats and the rear storage area.

I have much better pictures, but the forum is not accepting them unless I downsize radically and/or lower resolution. I understand the server requirements and don't usually have any problem, but something is different recently.