Vacuum brake conversion and now a stiff pedal

[85supreme]

Hey guys, I just got done my vacuum brake conversion with a reman booster and master cylinder. The problem is the pedal is hard and the brakes aren't that powerful. It kind of feels like manual brakes right now.

I was going to try and bleed the system again, but wouldn't air in the system make the pedal soft? Also, does anyone know what size the bleeders are on the front brakes? I was having a lot of difficulty finding the exact size and don't want to round them off.

I have the vacuum block from kirban's and I'm using a vacuum hose off a non-turbo car, however, it has a check valve in it before the hose gets to the booster? Is this still necessary on our cars? The system seems to be drawing vacuum since I can hear the engine idle change a little bit when I press on the brakes. Could my problem be the system not getting enough vacuum?


Let me know what you guys think. I'm going to try and re-bleed the brakes tomorrow.

Thanks,
Mike

 

[pacecarta]

caliper bleeders are 10mm ,rear are 8mm

sounds like either you dont have vacuum or you have a bad booster
is the check valve at the booster sealing ?

 

[85supreme]

I forgot to add that when the car is in park the pedal feels more like how a power brake pedal should, but then when I'm driving its harder.

I'm going to check on both valves tomorrow and get back to you guys

 

[tzque]

Change your rubber brakes lines before you do anything else . The lines swell which create all types of problems . I wished i had gone stainless steel but did not . I wish someone had given me this advice

 

[2QUICK2B6]

mine worked fine with srock rubber lines but I redid my front brakes ... as mentioned above the rubber brake lines could be the coulpret

 

[MG8T7GN]

If you pull the hose off of the booster with the engine running and put your finger over the check valve, do you feel a strong vacuum? With it all connected and the engine running, slightly press on the brake pedal, do you hear a hissing noise? Did you install a vacuum brake pedal?