2nd Gen Non-Engine/Transmission Hard brake pedal on start-up?

[BigPapa]

It started yesterday. Get in the truck, push in the clutch and take it out of gear, foot on the brake and it's hard and no brakes until the engine starts and the power brakes comes up. Push it hard as I can and nothing until the engine starts. Almost ran into my wifes Jeep in the driveway last night. It's been in the 20's past couple of days but the trucks warm and been driven within 30 minutes every time this has happened. It was fine this morning after sitting 7 hours last night. Temp was right at 20* when I left this morning.



Scott

 

[kenny61]

Mine started doing this years ago after the dealer replaced the vacum hose to the booster on a recall. I went back and complained but they said it was supposed to be like that. It wasn't worth my time arguing with them. I'm used to it and make sure the ebrake is on or I'm pushing real hard on the pedal if there is anything down hill from me. I'm guessing there is some sort of check valve to keep the vacum in the booster but never bothered checking

 

[BigPapa]

Just drove it again. Started it twice and no problem now.



Scott

 

[kenny61]

Mines like that somedays its good some days its not, Sometimes takes a couple of days parked to get hard other time it maybe a couple of hours. when I restore my truck in a few years I may get around to fixin or at least looking at it

 

[CumminsPower98]

Yes there is a check valve where the hose connects to the booster. This check valve could be leaking or the booster and allowing it to bleed off.

 

[Joe Mc]

What about the small blue can on the booster assy? Isn't this a nitrogen reserve that allows for 2 or 3 stops without assist ie: engine dies as you're going down the road = give you some assist to stop. If this reserve bleeds off as the truck sits, till the boost comes up after start up, then the pedal will be real hard. Just a thought? There still seems to be a leak somewhere though?

 

[CumminsPower98]

We are talking about pre hydro-boost trucks that use vacuum.