no brake pedal ??

[bdydrp97s10]

i did a power brake conversion on my truck from manual brakes

ok i replaced all the brake lines front to rear with new hard lines and rubber lines...

i put a brnad new master cylinder on the truck..

when the truck is running the pedal pushed to the floor very easily like the lines havent been bled.

but i have bled the about 4 times just to make sure theres no air in the lines and there isnt.. there is also no leaks anywhere in the system..

whats wrong here could it be the booster??? im not sure because somebody tols me when your booster goes bad you have a really hard pedal..

sombody help me because this is the only thing holding me up from getting my truck on the road after a complete resto

[vin63]

Did you bench bleed the master cylinder?

[AustinScott]

Originally Posted by vin63

Did you bench bleed the master cylinder?

priming the master cylinder is a must, either on the bench or in the truck.

Also, you could have a VAC leak in the booster.

Do a search, I'm sure there are a few tips already spoken of to help narrow your problem down.

[Scottshotrods]

do you know how big your
bore size is example
1 bore or 1 1/8 bore
are you running disc and drum or disc and disc or
drum and drum?????

[bdydrp97s10]

did not bench bleed, but since i have bled them four times and the last three turned up no bubbles, im sure there no air in them... this method has worked for me before..

bore size???? no clur stock power brakes from a 71 or 72..

disc in front, drum in rear

how would you find a vac leak at the booster

[vin63]

Originally Posted by bdydrp97s10

did not bench bleed, but since i have bled them four times and the last three turned up no bubbles, im sure there no air in them... this method has worked for me before..

I would bench bleed the master cylinder just as one of the items to check off in going through and systematically rulling out the problem with no brake pressure. You can have no air in the lines, but you can have air in the cylinder...you can't tell until the system is closed because it does not take much pressure to force the brake fluid out of the bleed nipple when it's open.