Brake travel/lights issue

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Supermike
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Brake travel/lights issue

Post by Supermike »

Hey guys... need some more help here!

Since I had my booster installed, the truck has been braking fine. There still seems to be to be a bit too much travel in the pedal, though. As a result, I don't think the brake light switch is getting enough pressure to trigger it, because it has to be depressed ALL the way (truck stopped, me with foot down on pedal) for the brake lights to come on.

Do you think this is a switch issue, or a brake travel issue? Would adjusting the pushrod more DECREASE the travel in the pedal?? Could this be a vacuum issue of some sort? Everything LOOKS ok, and the truck slows and stops OK, but this has me puzzled. I definitely need to fix it, though!!

BTW, the switch is brand new. I'm going to try and swap in the old one and see if that helps, just in case I got a bad/faulty switch.

:? :hmm: :dk:
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seattle67
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re: Brake travel/lights issue

Post by seattle67 »

Does it take less pedal after you pump it? If so, that would indicate air in the brake system. Otherwise I would suspect the adjustment of the push rod between your booster and MC may be a bit on the short side.
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Supermike
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Post by Supermike »

Thanks Dan...

Not really... even with the truck off, I still have to press it all the way down to get brake lights. I'll pump it some tomorrow to see what happens. I guess I'll screwball with that adjustment over the weekend, though I'd hate to get it too tight.

So that I'm clear, I should be able to just unbolt my MC from the booster, lean it away, and adjust that rod, right? (I didn't do the installation...)

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hi-fi-guy
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Post by hi-fi-guy »

Take a look at the brake light switch itself and see if it isn't gunked up with something. Mine comes on with minimal pressure. The only way I can see a switch taking that long to come on is if it is sticking and closing slowly.
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seattle67
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Post by seattle67 »

Supermike wrote:So that I'm clear, I should be able to just unbolt my MC from the booster, lean it away, and adjust that rod, right? (I didn't do the installation...)
Yup, that's correct, it's fairly easy. You just want to be careful with the brake lines attached to the MC, don't want to kink them.

You can check the adjustment of that rod before you pull things apart, but you will need two people. With the engine off, pull the cover off the MC, then have someone push slowly on the brake pedal as you watch the MC. If it is adjusted correct, some brake fluid should squirt up in the bowl after they push the pedal about 3/4 to 1 inch. If they have to push the pedal further, then the rod needs to be adjusted longer. If it takes less pedal movement then that or if fluid never squirts up, then the rod is already too long.

Two hints, do small adjustments on the rod and put the cover back on the MC before you unbolt it! :lol:
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Supermike
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Post by Supermike »

Thanks for the advice... I'll check it out this weekend. I pumped it this morning and it didn't really make much of a difference.

The only other thing I've noticed is it seems the brake light switch moves/pivots up a bit when the pedal is pressed in so far (as if it were being pushed DOWN in the back). Does anyone have a picture of how the '67 switch SHOULD be properly installed so I can check that? Maybe the switch is on wrong??
seattle67 wrote:Two hints, do small adjustments on the rod and put the cover back on the MC before you unbolt it! :lol:
LOL! You must know me pretty well! :D :wink:
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re: Brake travel/lights issue

Post by Thunderfoot »

Shayne
I'm not "Brand Loyal" Ford-Chevy-Dodge-Toyota I have them all, one even cross mixed...
If it Looks good and Works good then it's ok by me. Everything has its issues from time to time...

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Supermike
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re: Brake travel/lights issue

Post by Supermike »

SteveC wrote:
There is the bolt a plastic bushing and a plastic ring that fits snuggly over the round part of the bolt towards the head of it. the bolt goes into the stop light switch then the plastic bushing goes inbetween the tabs on the switch and the bolt continues through the tabs where is is head in place by the ring that snugs over it and that bolts to the peddle.
I have the bolt and a plastic bushing between the tabs on the switch, but I do not have a plastic ring.

Is this different for the '67s? Or am I missing the plastic ring? Also, on which SIDE of the bolt, once between the tabs, does the bushing go (left or right)?

Also, my bolt is held in place by a nut, not by a ring? So I'm confused as to what he means by "held in place by the ring that snugs over it and that bolts to the pedal" (paraphrased).

Can anyone/someone please clarify? :dk: :help:
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Supermike
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re: Brake travel/lights issue

Post by Supermike »

Ok... I MAY have fixed it... I took the switch off. The bushing was set in the push rod from the right side (the "U" side of the switch). It looked like it had kind of gotten hung up there, so I moved it to the left side ("O") and then slid the switch back over it. I then made sure the bolt passed all the way through and tightend it back to the pedal.

It sure looks to me like there could be a missing spacing ring of some sort, as there looks like a lot of "play" in the switch movement to me. But anyhow, I tested out the wires to make sure the one with juice went to the "+" (positive) and the other to the "-" (neg/ground). I'm not 100% convinced those weren't crossed previously, but I failed to verify it before I unhooked it.

At that point, I had functional brake lights. But to be on the safe side, I pulled apart the MC and booster and lengthened the push rod by a couple of turns. Not much... maybe 1/8" or so. I probably could have gone more, but I didn't want to screw anything up.

So let's hope it keeps on working! Thanks for your help, guys! I'm still curious about the mysterious "ring" that Steve referred to. Am I missing some kind of plastic spacer washer?

:fr:
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