Brake

[MarvinElliott]

Hello I have a 84 and about 6 months ago I lost my pedal and me and my dad put a new master cylinder on it and we blead the brakes and it had a good pedal but as soon as you start it you loose the pedal and it doesn't break very well and if you press the brakes fast it wants to die what do y'all think is happing

[dlb]

My first guess is you still have air in the lines and need to bleed all four brakes more. My second guess is your brake booster has a hole in it. Suck on the hose that goes to it and confirm that it holds vacuum like it's supposed to. If it doesn't hold vacuum you need to replace it.

[MarvinElliott]

Thanks

[MarvinElliott]

Hi so if I suck on the line you can hear something happening in the booster but I can't blow in it

[SirFoxx]

Hi so if I suck on the line you can hear something happening in the booster but I can't blow in it

well yea, youre not supposed to do that. depending on where youre sucking, you may be pushing against the check valve. but, yea if it wants to stall when you hit the brakes, its 100% the booster.