The Stovebolt Site Forums The Shop Area Engine Shop Who needs brake lights anyways?

Here we go again...No wonder the previous owner had the brake lights on my 51 3100 connected to the running/tail light post on the headlight switch. I thought he was brain dead and fixed it, be darned if the battery wasn't dead half the time. Stupid me, turns out that the brakes work great, but the pedal doesn't come all the way back up to the top, so the brake light switch doesn't completely close, allowing the brake lights to stay on all the time running or stopped and kill the battery(coulda swore it was that twilight sentinel those fancy Caddies have). I've been peeking around, read a vague reference to a return spring in the master cylinder in the shop manual, but nothing about servicing, checking tension, any of that stuff. Anybody have any ideas that'll keep me from having to turn the park lights on so I don't get smushed from behind? It's more fun at night, when I just have to reach down and hold the pedal up the darn 1/2" while running through the gears and cruising down the two lane(officer, you aren't gonna believe this, I know I'm swerving, but no I wasn't drinking) I'm going to make my wife ride in the bed if she keeps giggling at me(don't worry, I'll make her sit on a blanket so she doesn't scatch the wood. She thinks I should use a rubber band from the brake pedal to me-guess where . Any suggestions? Thanks, sorry for the long post!

You are too funny!!!! I'll check my 52 pedal set up and get back with you soon.......

There is a spring inside the master cylinder, but also on two different setups I've seen for a single cylinder master there's also a fairly strong return spring that attaches to the pedal and then the frame (there should be a small hole on the pedal lever) ... do you have this spring and is it just too weak, or is it missing? Also, what about just adding a 1/2" spacer between the stoplight switch and the firewall?

had the same problem on my 51 brake lights stayed on. It turned out to be the brake pedal arm/shaft was hiting aginst the floor board, enlarged the hole a little no more problem. Good luck Bill

In that case your cab mounts need replaced. They're made of rubber, and when they fail the cab shifts to the side. And they're not that hard to replace.

thanks fred I will check out the mounts. Bill

Let's assume that the cab hasn't settled a half inch and there's a return spring on the pedal arm. If the pedal isn't coming all the way up, you need to lengthen the pedal shaft. You should see an adjustable coupling on the shaft coming out the front of the master cylinder. Be careful not to over-adjust or you'll be pressurizing the M/C and get spontaneous brake locking.

I have the same problem on my 56 also. I put a second spring on it and works most of the time.
Brad

I just fixed mine yesterday. I was doing the EXACT thing on my 54 ton truck, with the foot under the brake pedal.

On my truck there are two springs attached to a bracket mounted to the side of the frame. One is for the clutch and the other one is for the brake return. Now, what I did was take the brake spring off and cut off about 3/4 of an inch off of the long end and bent another hook on it and this added more tension on the spring and worked like a charm. I even tried bending the switch arm some so the brake arm would make contact sooner and would start breakig the contact, didn't work. The cutting off the sping trick did the trick. I suppose after years of use the spring gets weak and doesn't have the tension it had at one time.

Good luck,

John Niekamp

I had the same problem on my '55 2nd series. First, I replaced the brakelight switch.

Didn't work.

Next, I added a 2nd brake return spring. I thought 2 springs would pull the pedal up better.

Didn't work.

Next, I took a piece of heater hose about 4 inches long, sliced it lengthwise, wrapped it around the brake shaft at the point where the brakelight switch contacts it, and fixed it in place with a hose clamp.

This worked. The hose makes the diameter of the brake shaft larger and pushes against the switch a little more.

LT

Hey there fellas, thanks for the suggestions. It appears the truck and I are a pretty good match, missing a few key pieces that'd make us work a little better. Unless I'm brain-dead, there sure isn't a return spring mounted for the brake pedal anywhere, and I'm kind of at a loss to where it would be. It comes so close to the firewall, I'm trying to picture where in the world it would mount.It shares the shaft with the clutch, but from there, not a spring to be found. Of course the pedal has quite a throw to it, but it comes so close....I guess I'd better spend some real time looking for a hole in the pedal shaft and an anchor point for the spring. Everything appears to be stock or close to it, and the drawings and descriptions in the shop manual match what's there, but again in the manual-no mention of a spring. LT, that rubber tube trick or tack welding a 4 or 5" piece of metal to that area of the pedal shaft is probably my best bet until the spring ferry leaves me a present under my pillow. Thanks again!

i had a similar problem .i simply couldn't mount the mechanical switch without a lot of adapting due to the frame change ,etc. so i went to a hydraulic switch . simply done with a T fitting coming out of the master cylinder , a series of fittings to the switch and done.

The return spring that everyone is refering to is located underneath the truck. It connects to the brake pedal below the pivot point. There should be a grease fitting on the pedal put some grease in there and put a good size spring on there and that should solve your problem.

Thanks Brian, I'll check that out tonight.