I have been helping a friend build a 38 Chevy pickup for a good bit now. Was going to try and make the Street Rod Nationals in Louisville, KY but am quickly losing interest in their new "Street Rod PLUS", which is another issue.
The truck is really looking good but I noticed something that has sparked a concern. When the engine is started without touching the brake pedal, it will drop by itself about 1-1/2". It is still not drivable to check the brake function so I can't tell you how the brakes are working for stopping power. It is an aftermarket under-floor power brake setup. The pedal rests quite a bit higher than I would prefer while the engine is not running but as I said, drops to about the right height after the engine is started.
I have never noticed one doing this before without even touching the pedal. Another thing I am concerned about is after applying the brakes while on jack stands and the engine is running, the front wheels will stay somewhat locked. I have to reach down and raise the brake pedal just a bit and the front wheels will release.
Everything is new and it has 2 lb residuals on the front and a 10 lb on the rear. I am going to have to change the 10 lb residual on the rear because I have since put disc brakes on the rear. I am also going to have to change out the proportioning valve because of this.
I don't want to have to put a return spring on the pedal because I don't like it being so high, the 38 Chevy truck cab is already so short your knees are in your chest when sitting in it. I tried adjusting the rod on the master cylinder but then the pedal will go too low to the floor when applying the brake. I thought I would toss this out there to see if anyone had any ideas.