I just finished a complete brake system restoration (wheel cyl., hoses and shoes) on my 61'. I also put in the dual pot master cylinder as described in this article http://www.earlycuda.org/tech/dualmaster.htm

My brake lights are staying on and it appears the brake pedal does not return as high as it did before the change over. The article states that the same pushrod was used for the 67' and up dual cylinder.


Has anyone else had this problem?

The spring and keeper around the rubber dust boot is in place.

The switch I have is similar to a 30 cal. rifle shell with a mushroom end on it that the brake pedal engages. It is held in place with a metal hanging bracket that is secured using 1 bolt and a tab that fits into a hole to keep the bracket from pivoting on the bolt.

Any response/input would be appreciated.

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Super Six Conversion Stromberg

Cant you adjust the brake light switch so it makes contact? Or bend the bracket so it will be closer to the brake contact area?

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Wife's: 64 Valiant
My: 70 Road Runner, 67 Barracuda, AND the 62 Valiant drag car!!

You should be able to adjust the mushroom button so it contacts the brake pedal correctly. If not, I am pretty sure you can ask for a 67up brake switch that will.

Brian

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Flyin' Brian

74 Duster, 225, rear-mounted blow through turbo at 12psi boost, street/strip car
"Sixy Beast"

If you are not happy with the hight of the pedal mopar makes a adjustable pushrod that may correct both problems.

I don't believe the newer pushrods are the same. I had the same problem with a dual mc on a 62. It was solved by finding the right pushrod in the pile at wildcat auto wrecking. It doesn't seem right to bend a bracket into a misaligned position that worked properly before.

good to know, 63 was the oldest for me.

anyone ever try one of these from Dr. Diff?
http://www.doctordiff.com/62-70-adjusta ... h-rod.html

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1964 Dart GT

damn double posts!

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1964 Dart GT

That looks sweet.

That looks sweet. Heim joint and length adjustable. I would like to add that to my next brake upgrade.

Thanks for all of the responses.

Haven't had any time to look at this problem any further but my thought is the piston on the new MC has a deeper well than the old single pot. Stupid me...I tossed the single pot so I have nothing to compare.

What I notice is the pedal height is lower, hence the problem with no contact of the brake light switch. Secondly, I can feel the push rod "clink" when I use my hand to engage the brake. That tells me there is some slop between the rod and well.

If my assumptions are true, then the only solution is a longer pushrod.

Thanks Danarchy for the Dr. Diff lead. I'll look into that one.

MotoGrey...I'm going to crawl the local yards here to see if a late 60's to mid 70's rod is longer....assuming I can find one! Most of the old stuff around here got crushed when the $ of steel went up.

I was also thinking I could modify a rod and making it adjustable by cutting it, threading it and getting a "turnbuckle" type threaded adjuster.



Here is an adjustable for Mopar from Master Brake Products out on the east coast. No specs available and it is $43 plus freight...an awful lot to toss away if it doesn't fit.

Lastly...if anyone has an early 60's push rod laying around and not needed, I'm interested. I'd like to try and make an adjustable out of it.

Thanks again.

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Super Six Conversion Stromberg

It won't take much, you will want to measure how short yours is then take it with you to compare the the ones you find. Be sure to mark yours so you don't mix it up while your comparing. Good luck.

Finally got back to this problem and pulled the MC. The push rod well depth is the same as the old single pot MC and the bushing and rod were in the proper position. I'm having a hard time wrapping my head around why the pedal height would change.

It looks like the previous owner wrapped some tape around the brake light switch. I'm wondering if it was sliding in the metal bracket that holds it. If it was, then that explains why I am not getting any switch contact with the pedal but.....the pedal seems lower.

I'm going to see if I can get some adjustment out of the switch and then see if I can live with the low pedal. I'll start crawling the yards to see if I can find a longer push rod or one that I can lengthen to get the pedal up higher.

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Super Six Conversion Stromberg

I did all that once in my last 62, the guy before me upgraded to the dual mc. The brake lights kept creeping back on. It didn't make any sense that the pedal or switch position would move. But I messed with it all any way in addition to condemning the mc that was on there. I replaced it with new everything measures up the same. I think there is something different in the set point of the piston in the bore.

All that said, what you need is a slightly longer brake pedal to mc rod.

Good luck, Ray

I suspect that's where I will end up. The trick is finding another push rod to modify. I'm not going to cut up the one I have. I like to keep my stock parts just in case. There is a yard....just one...that may have what I need but around here most of the old stuff got crushed long ago.

If anyone has a push rod they can let go of, pm me with a $$. Thanks!

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Super Six Conversion Stromberg