Vacuum brake conversion
When I quickly apply my brakes like in a panic stop it feels like there is a restriction and there is a resistance to depressing the pedal any faster and then gets easier. I am unable to lock the brakes unless I use both feet. The farther down the brake pedal is depressed it seems like it starts to get harder to press again. If I apply my brakes slowly like in normal street driving the car slows down normally. I've owned an 85 Olds Cutlass in the past and I know how vacuum brakes supposed to feel and react to panic stops. I've converted to vacuum brakes since 2007 and the car has hardly been driven due to the brakes. I bought and installed the vacuum block with a vacuum fitting from Kirbans to insure I had adequate vacuum to the vacuum booster assy. I've replaced the rotors and rebuilt the front calipers. The vacuum booster is a new rebuilt unit from Carquest along with a rebuilt MC also. I've installed the MC and vacuum unit that was working great in my friend's car into my car and the symptoms were the same. I did not notice any problems similar to this before when I had the PowerMaster. The only thing I can figure out might be the proportioning valve since it also has a metering valve which might be stuck in the slightly closed position and thus restricts the hydraulic pressure from going to the brake cylinders unhindered. I hate to just throw parts at the car so I thought I'd post my problem with the brakes in hope that someone might have had similar problems in the past.
I have the proportioning valve but I have found some other issues , I think because of the high pressure developed by the hydro boost , it will find any problems , first thing I found , I had a guy install line lock , he put it before the proportioning valve its instructions say to put it after , so it could cause trouble , the double flares he did , were not perfect very tiny leak , a leak also sucks air in . with the car running , turned steering wheel very hard ( to the max) found the brand new pressure hose at steering box leaking . I think some of my troubles were from me not taking it serious enough , inexperienced , its a job that you can t leave any stone unturned , nothing left to chance heres my e-mail if I can help kellycameron493@gmail.comI'm having the exact same problem with a vacuum converted system on a car I just bought. I'm going to swap the prop valve and see if that helps but besides that I'm stumped on what it could be!
I think I mentioned it already above, your proportioning valve pin may not be centered.Can anyone help , I just did hydro boost conversion , having some issues , one of them being , I read you can get a better bleed if you push in plunger ( the one facing front of car ) my plunger looks different as far as theres a pin sticking out that can t be pushed in ? it sticks out , 3/8 of an inch , the pictures I am seeing , they don t have the pin ? it can pull out a bit but not push , any help would be appreciated Thank you