No brakes when cold

[yeast]

I haven't noticed this problem except when it is fairly cold (<20F). In the morning, I have no brakes until I pump the pedal several times while sitting in park. At the same time, the truck is warming up. After pumping a few times, the problem goes away, and doesn't come back until the truck sits for a long time. When I first turn it on, there is some stiffness in the pedal, but if I try to stop, the pedal goes nearly to the floor and there is little to no braking action.
This is on a 92 3.0VZE AT pickup. All components are stock/original--no lift, 31" tires, etc.

I replaced the rear brake cylinders and shoes a few months ago, and have never had any problems when the weather was warm. At the time, the parking brake was adjusted and the rears would hold the truck, even if it was in drive. Now, the parking brake doesn't seem to catch at all, but only when cold.
I'm going to pick up a set of speed bleeders and do everything this week, including the LSPV, which I did not previously bleed.
Should I bleed the master cylinder? Is this problem indicative of a bigger issue?

 

[KLF]

When you did the rear cylinders, did you bleed out all the old fluid? Could be some water in the lines which is freezing.

It also sounds like the rear shoes are out of adjustment. Do you use your parking brake every time you park? This is what keeps them in adjustment.

Personally, I think those Speed Bleeders are a waste of money. Snake oil.

 

[Devils Paw 80]

Personally, I think those Speed Bleeders are a waste of money. Snake oil.

They don't work well. If you can't find a partner, I'd go for a vacuum bleeder.

 

[KLF]

My experience with them was that they still worked fine as a bleeder, they just didn't help at all. I couldn't tell any difference.

I tried a vacuum bleeder. Another waste of time, very frustrating. They just suck air through the threads of the bleeders.

Pressure bleeder is the way to go.

 

[missouriman]

on my cruiser I had the same problem, check your booster, is there a rubber grommet with the check valve sticking out of it? Your truck is a lot newer then my mini's. Any way I replaced the grommet and the check valve. they work well now.