Blake Breeder!

Dudes,

I ran new brakelines in a '59 Cad & installed new dual master power unit. I've bled the brakes until there is NO air. Brake shoes (4 wheel drums) are adjusted properly & the pedal is adjusted as "high" as it'll go. We are getting no leaks at any of the flares. The brakes only stop the car if you SLAM them. Gentle pressure does nothing. WTF?

Anyone had this issue before?

Thanks,
-r

 

New master? What's its out of or intended for
Did you change any thing else?

Pedal ratio, push rod issue, bad master

 

Did you bench bleed the master before installing it on the booster?

 

Fix the ***le of your post and you will get more responses. No one remembers Blake Breeder!

 

Who's blake, and being your randy i doubt you two can breed. But i would say bad master cylinder rubber cup deal. I was just thinking and maybe its the vacuum, when you mash on it it gets all the vacuum but when you just ease on it you dont get enough vacuum.

 

Do you have a good va***e supply?

 

If its the stock unit dont they have a big vacuum tank under the car?

 

I'd be checking the booster system. It sounds like the brakes and hydraulics are ok.

 

Thats my thought also.

 

Yup. Good Vacuum supply. I don't really know the pedal ratio, but I can't bottom the pedal against the floor, which means it's bottoming w/in the cylinder.

I bench bled the M/C before install.

It may be a Disc/ drum M/C being used on a Drum/drum set-up. How problematic is that.

The M/C & booster is from ECI & looks like this:

Thanks again!

 

Problematic enough to where your brakes wont work

 

There's no problem at all using a disc/drum or disc/disc master in a drum system. Just add external 10 lb residuals going to each axle if the master you use does not have them internally in the drum outlet port. (on some early disc/drum masters)
What is the bore of the new master, vs the original?

 

Here's some reading that should explain the problem, I suspect bore size in your master cylinder or pedal ratio is the problem (or both) -

http://www.mpbrakes.com/technical-support/reference-master-cylinders.cfm

Effects of Pedal Ratio and Bore Size on Hydraulic Pressure Output
<TABLE border=0 cellSpacing=1 cellPadding=3 width=595><TBODY><TR><TD cl***=tdName width="25%">Pedal Ratio</TD><TD cl***=tdName width="25%">Bore Size</TD><TD cl***=tdName width="25%">lbs input</TD><TD cl***=tdName width="25%">PSI out</TD></TR><TR cl***=trLight><TD>6:1</TD><TD>1 1/8</TD><TD>75</TD><TD>453</TD></TR><TR cl***=trDark><TD>6:1</TD><TD>1 </TD><TD>75</TD><TD>573</TD></TR><TR cl***=trLight><TD>6:1</TD><TD>7/8</TD><TD>75</TD><TD>748</TD></TR><TR><TD colSpan=4><TABLE border=0 cellSpacing=0 cellPadding=0 width="100%"><TBODY><TR><TD bgColor=#000000></TD></TR></TBODY></TABLE></TD></TR><TR cl***=trLight><TD>5:1</TD><TD>1 1/8</TD><TD>75</TD><TD>377</TD></TR><TR cl***=trDark><TD>5:1</TD><TD>1 </TD><TD>75</TD><TD>477</TD></TR><TR cl***=trLight><TD>5:1</TD><TD>7/8</TD><TD>75</TD><TD>623</TD></TR><TR><TD colSpan=4><TABLE border=0 cellSpacing=0 cellPadding=0 width="100%"><TBODY><TR><TD bgColor=#000000></TD></TR></TBODY></TABLE></TD></TR><TR cl***=trLight><TD>4:1</TD><TD>1 1/8</TD><TD>75</TD><TD>302</TD></TR><TR cl***=trDark><TD>4:1</TD><TD>1</TD><TD>75</TD><TD>382</TD></TR><TR cl***=trLight><TD>4:1</TD><TD>7/8</TD><TD>75</TD><TD>499</TD></TR><TR><TD colSpan=4><TABLE border=0 cellSpacing=0 cellPadding=0 width="100%"><TBODY><TR><TD bgColor=#000000></TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE>

 

I thought Breeder had a brother for a minute???

 

have you checked the wheel cylinders to see if they are frozen? are the shoes lubed were they meet the backing plate?? maybe a proportioning valve problem??? just some easy things to check out first.

 

Pedal ratio, pedal ratio, pedal ratio!!! Cured the EXACT same problem I had. Went through THREE brand new MC's before I finally checked the pedal ratio. Guess what it turned out to be...PEDAL RATIO. Cured it as fast as it took to drill a new mounting hole for the push rod in the brake pedal arm...

 

how about a pic of the booster in the car/peddal ***m.

 

Yeah...kinna freaked me out! Started thinking I knocked up one of the vagabonds at the hamb drags or something!

 

did you change the flex hoses also.

 

Thanks guys! I'm on it. pretty sure it's the ratio at this point. Hopefully will be fixed tomorrow.

-r

 

I don't build anything with power brakes but race cars or hot rods I always make the pedal ratio 6 to 1. hope this helps, power brakes maybe ,probably are slightly different.

 

When I first bought the 63 T-bird,brakes required maga presure at the pedel untill I found the primary and secondery needed to be put in their proper place.

 

Did you call ECI? They will probably tell you that the push rod is not adjusted right...You ask here before you ask there and you will get a lot of answers that are total guesses and just plain wrong because your OP wasn't read...Yes there are some good suggestions but which are those? Hit up ECI...