1982 F350 weird brake issue + Oil Pressure

[mylawnwi]

Brakes:

Hello all!

I have an 82 F-350 with a 351.

The other day my partner was driving the truck and he said all of a suddent the brake pedel went to the floor almost all the way & the brake light came on. He was able to stop but it took a lot to stop it. He was then on his way to an auto shop to get an emergency check and half way there it came back to normal. Now the truck is back to how it was. We bought this truck like 2 months ago and this is the first time it happened and hasent happened since.

I need to figure out if I need to replace the Master or booster or what. We can not afford to loose brakeing towing a trailer or anything.

Any opinions?

When the truck is running or not running I can hit the pedel and it seems to stay and not leak to the floor either.


Oil Pressure

The oil pressure is up a bit over half way when the truck is started and running for a while. It slowly goes down and down till it gets just a bit below the L on the gauge. The truck seems to still run fine with no noise. I am not sure if its the gauge but it seems like it wouldn't be since it works at the beginnig so I don't know.

I do not want to have the motor crap out on us or anything. Can you guys help me on this. Is it common?