Brake question

4 wheel disc system, Lincoln Versi (sp) rears, new fatman up front, new 8" power booster and double res master. Proportion valve. This thing has the longest pedal in the world...6" of throw and then really good brakes. Stops fine. little wierd on the long throw. It also has a brake pressure swith in the system ands brake light's do not come on till pedal fully engaging brakes.

I am lost, as a few others who have looked at it. Help me out guys. Please.

 

master bore size? caliper bore sizes?

 

I do not have those answers for you.

 

You can change the pressure switch out for a low pressure switch that will come on with very little pressure..

 

until you get those answers it is just speculation.

 

I'll take some speculation and in the meantime I will find those numbers.

cwayne thanks for pressure switch idea!

 

Sometime ago I read an article about Lincoln Versailles rears and brakes. It said that in order for the disc brakes to work properly you must use the stock rear brake adjuster mechanism that comes with the stock Lincoln Versaille rear, other wise the rear brakes won't operate properly.

 

What is your brake pedal ratio? That ratio is found by comparing the center to center distance of the pedal pivot to the center of the M/C pushrod versus the distance from the pedal pivot to the pressure center of the pedal itself. For manual brake systems it is typically about 6 to 1........for power systems about 5 to 1.

While it may not be a factor in your particular case, if excessive (say 6 to 1 or greater) it certainly can produce what you are describing. Of course, as suggested by Scarebird's questions, M/C bore and caliper bore are also significant factors that could have the same result. Sometimes it amounts to some of each factor not being optimal rather than just one cause.

Ray

 

Thanks all, still working on bore sizes. The brakes are set up as they came off the car. The rear end may have come out of the Lincoln as a matter of fact. My brake ratio may be too high based on the formula above. Lots of good info thanks.

 

What are these deminsions you have ?

 

True on the Versailles rear calipers.

The e-brakes must be hooked up and working in order for the pad adjusters to work. Not the greatest design and I don't think there's a better bolt on replacement caliper for those either. And unfortunately the Versailles rear also has unique backing plates and bearing retainers, so you can't even bolt on other 9" stuff.

It was the hot ticket for rear discs in the late 80's/early 90's, but there's better/cheaper/easier ways to get discs these days.

 

Thanks. That is what I was trying to remember.

 

I agree with CWayne I had the same issue. In my situation I swapped out my pressure switch and problem solved. Good luck!

 

how much pedal effort do you have?

 

Let's see if I can answer all. Brake ratio is x(16)y(2.5).

Master cylinder bore is 1 1/8, 9/16 ports. no idea what the Lincoln caliper bore is.

Petal effort is a nice power brake easy pedal, little effort.

The brakes and parking brake are all hooked up and working well, adjustments etc...

Someone has said that possibly Explorer drums etc.. may work.

Thanks again.