Weird brake function

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Oct 14, 2018 | 09:01 AM

Shawner1974

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Joined: Feb 2018

Posts: 108

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Weird brake function

Good morning all! I have a strange problem with my brakes. When it is warm out, they work great. When it gets down to 40 degrees, the pedal is very stiff until the truck warms up. I thought maybe it was condensation freezing but it's not that cold yet. Vacuum seems to be ok, although I haven't checked it with a gauge. I do have a new master cylinder/booster I have not installed yet, but I'm not sure that will solve the problem. Any ideas?

Oct 14, 2018 | 02:03 PM

CharlieXLT

Tuned

Joined: Sep 2017

Posts: 402

Likes: 18

From: Warren, Texas

Vacuum booster. When it's cold, parts have contracted enough to cause a leak at a bad spot. As the engine bay warms up, parts expand and the leak starts to seal up. Years ago, a friend had a 73 Duster with power brakes that did the same thing in the winter. He was always a broke-*** college student with no money and couldn't afford a new booster so it stayed that way for a long time. Finally got one for free from a friend that wrecked and totaled a 73 Valiant. Brakes on the Duster worked perfectly after that.

Kinda the same thing happens with cold solder joints on a printed circuit board. As a piece of electronic equipment heats up or cools down, the poor solder joint either makes a better or worse connection due to expansion/contraction.

I'm sure once you get that new booster in, that problem will go away. Don't forget to replace any vacuum hoses that you think might be questionable looking. Good luck!