Brake problem confirmation

[FJ45KC]

I have been working on a brake problem for a few weeks on my Dad's 79 FJ40 that has me a little stumped. I have rebuilt the master cylinder once and subsequently replaced it due to the follwing problem. When you push the brakes initially, they work great. If you push them for a second time immediately after, the pedal moves an inch and stops and won't go down any farther (with immense pressure). The truck simply won't stop when this happens. I posted this on Cool Cruisers and the response from only one person was the booster was bad. Could it be something else? I ask this because it doesn't feel like my manual brakes on my 66 FJ45. The pedal feels like it is up against the fire wall.

I appreciate any and all insight.

Casey

 

[toddslater]

It does sound like a booster issue. Your 66 has drums all round with MC sized and designed to be non boosted. The 79 has discs up front with a MC that is sized and designed to be boosted. Do a search here and you'll run across the booster check procedure.

 

[bad_religion_au]

pump your brakes, hold them down when their firm, start the car, if the pedal moves in, the booster is working

 

[FLYINGLOW]

Ignore me if you've checked already, but is the peddal fully returning? Adjust the brake pedal like in the manual. If you don't have some free play at the top of the pedal stroke pressure will build up in the system till you blow out your seals. Same goes for the clutch, just ask Radd Cruisers.