Hard brake pedal

[samedaze]

Just converted my 65 Coronet to power disc brakes, was manual drum, bought the complete kit from right stuff, booster,master,calipers etc, even ran all new lines. Bleed the brakes,bench bled master first everything fine,start the car the pedal is hard as a rock, they hold the car but you need Incredible Hulk legs to push it. Ck vacum 14 psi though was good but hooked up to a higher source to check no change. Checked and changed booster nothing, ck'd valve in booster , no change. Rebled brakes,nothing, no binding in pedal,even tried a new master cyl. Anybody ever come across this It's probably something stupid I'm missing but for the life of me I just don't get it.

 

[Photon440]

Out of curiosity, does it stop the same with the engine off and no vacuum?

 

[Car Nut]

Did you change your booster to brake pedal linkage? I believe the manual linkage is different than power.

Check out the Ram Man videos,
http://www.theramman.com/support/videos/90-mopar-power-brake-basics.html

 

[samedaze]

Out of curiosity, does it stop the same with the engine off and no vacuum?

Yes it's the same.

 

[sleepar]

When I put my SSBC system together the master had a a rounded table spoon of casting sand in it and after scrapping and digging it I got most of it... there must be contaminants in the system binding holding up the pistons...I would open a bleeder on the drivers side with the caliper off the car hung upside down with a block of wood where the rotor would be so the piston doesn't fall out (with a soft wood you should see where it wants to dent the wood )with a clear line and the breeders backed way out and give it both feet to see if it's packed with grit... I have had a piece of the flareing tool break off in side the line when bending them up before and if I didn't catch it would block off the system... another thing if everything thing is good.... those kits come with an adjustable proportion valve and if that is turned off or mostly off... it could block the flow... is that centered up 50/50 to start? Just some ideas....

 

[samedaze]

I cleaned the master before bleeding , then bench bled it , also bled the brakes twice. I also tried with and without the pro portioning valve still no change. Some places have said you need 18-20 " of vacuum so a friend of mine has a vacuum pump I'm going to try.

 

[sleepar]

Calipers working or froze...

 

[samedaze]

They work fine even took off drum and checked one at a time to make sure there was no binding and working as they should.

 

[Budnicks]

Is there still a residual valve inline ??
especially on the front portion ??
from the original drum brakes

 

[samedaze]

Is there still a residual valve inline ??
especially on the front portion ??
from the original drum brakes

Put in all new lines.

 

[SteveSS]

Let me know what you find out. On the 1969 Charger I just bought it has PB but you have to stand on them even going slow. Also my leather seats are like sitting on a wood bench. I'll have to check this one out.

- - - Updated - - -

Oops sorry mine are drums. We did the fronts on the Challenger, rear drums. it stops on a dime.

 

[coloradodave]

I cleaned the master before bleeding , then bench bled it , also bled the brakes twice. I also tried with and without the pro portioning valve still no change. Some places have said you need 18-20 " of vacuum so a friend of mine has a vacuum pump I'm going to try.

Generally, you only need 12-14" for the booster to work fine. You might try isolating the front and rear system and seeing if you can narrow down where the problem lies.

 

[sleepar]

Are you using the hard ceramic shoes... they don't tend to grab as much but last longer....
Someone started a thread about ventilated drums on here a few months ago... I'll find it and bring it. Up to the front....

 

[coloradodave]

Are you using the hard ceramic shoes... they don't tend to grab as much but last longer....
Someone started a thread about ventilated drums on here a few months ago... I'll find it and bring it. Up to the front....

Poster installed power discs...

 

[bigmanjbmopar]

I was going through the factory service manual last night for rear drums and ran across trouble conditions one being hard brakes, it said could be bad power booster.

 

[samedaze]

I was going through the factory service manual last night for rear drums and ran across trouble conditions one being hard brakes, it said could be bad power booster.

Tried two new boosters,that was the first thing I thought.

 

[bigmanjbmopar]

Right out of the book

 

[Photon440]

Well there's your problem...new boosters. Nothing built past 1978 is going to work right.

 

[samedaze]

Right about now I'm ready to take everything out and set it on fire.

 

[sleepar]

2bad boosters.... I've already gone on a rant about my SSBS system... don't feel bad everyone is having quality control problems with new stuff.... don't hurt the car... I'm planing on a trip touring these places.... like summit and some others to do some vandalism...