brake pedal sucked to floor on engine start
 

I drove my 81 F-350 the other day and the brakes were fine. I parked it for a while and started to drive it about 30 minutes later. But when I started the engine the brake pedal was immediately sucked to the floor. I could not pull it back up. When the engine was shut down the brake pedal would rise back up. I held the pedal and restarted. It took all I had to hold it up where I could move the truck. It's like the invisible man presses the brake pedal down when I start the truck. I replaced the brake booster about 8 months ago. Now I’m wondering if it has failed. Any help is greatly appreciated.ffice:office" /><O:p></O:p>

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Remove and plug the big vacuum hose to the booster (or hydra vac) and if the pedal stays up than it can only be the booster.

booster sounds like its not to bad to replace. make sure for some reason the hose pounts down if i aint mistaken

I had to replace my power brake booster on my 86 F250 and it was a pita to do.My son had to pull my steering column cause the bolts had froze in place other than that it was easy getting it out then back in.

I changed my booster in about 15 minutes. Not hard at all. If you replace the master cylinder at the same time it's a little more complicated because you have to blead the system, but it's not tought. Bleading brakes is basic auto 101 stuff...