The Stovebolt Site Forums The Shop Area Driveline brake troubleshooting

hey, i have a 1959 viking and i removed all 6 wheel cylinders and the master cylinder, honed them out and bought and installed rebuild kits for all of them. I then bled them untill i was positive all of the air was out. when i though i was done i pumped the pedal a few times and the pedal got hard about half way down but once i let off and pushed the pedal about 5 seconds later it went to the floor. i then pumped it another 3 times and held it when it got hard and it did not lose any pressure even after holding the pressure on it for about 5 minutes the pedal still remained hard. If anyone has any idea what might be going on i would sure be greatful to any help or suggestions! thanx!

That one's pretty easy. Fluids are not compressable, gasses are. You still have air in your brakes somewhere.

did you adjust the shoes out????how are you bleeding the brakes???

Isn't a Viking the big bolt model? Does it have a Hydro-Vac? You have to bled it out also, before the wheels and after the master.

doc41, thats a good point i did forget to adjust the shoes back out but would the pedal ever get hard with them not out? And ya it is a big bolt with a hydro-vac and i bled it there and im preety sure i have bled the entire system fully. do yall think its possible for the seals in either the wheel or master cylinders to seal under pressure but then loose seal when the pressure is taken of??

Usually with air in the system, there is a distinct feeling like you are compressing a spring. Is the rear brake setup like the old twinplex system with one shoe on top and one on the bottom? In that system, the wheel cylinders are vertical and the bleeder is in the middle. I believe that you have to back off the adjusters on the top shoe before bleeding the cylinders.

If you didn't have the shoes adjusted out properly after, then it may be causing your problem.

Just asking, but did you bled both bleeders on the Vac? Theres one on top and one on the bottom.

no i only bled one of the bleeders but i am preety sure its on top but i will definalty look at that. thanx!!

If you replaced/rebuilt the master cylinder, did you bench bleed it before doing the brakes at the wheels?
Dano

to be quite honest i dont know what you mean by bench blead so...no i didnt

I think it's shoe adjustment. The 3 or 4 quick pumps pushes the shoes out and fills the wheel cylinders a little each pump. The one slower pump empties the master cylinder before it can fill the wheel cylinders. My $.02. Good luck.