Willwood Calipers One Last Time.

[NY Twin Turbo]

Guys,

I have asked before, but I need a conformation from all of you before ordering.

After going back again and checking previous threads, I have determined that the best caliper for my aplication is the Willwood 40-12097R. This is the single piston replacement caliper. Yes??

See attached photo. My combo is as follows........

-Willwood manual MC (don't remember bore size but recommended by Willwood).
-Completely new 3/16" stainless steel brake lines throughout front to back. (no 1/4" anywhere anymore).
-Stainless braided flex hoses at both caliper connections and axle.
-5 PSI residual valve to the rear brakes only. Located just a few inches from the proportioning valve.
-Willwood adjustable proportioning valve.
-Stock rear drum assembly with the standard S-10 big shoe modification stuff. (I hate doing my rear brakes. Brian Cotton does them).
-Stock size replacement cross drilled and slotted front rotors (SSBC or EBC, I don't remember)
-Stock brake pedal assembly with an adjustable push rod and I used the Powermaster mounting pad for the new MC.

Problem- is slightly too much travel prior to brake grab.
Answer- I need to install a NON no-drag caliper.

Please confirm.

 

[NY Twin Turbo]

Bump.

I'm sorry. I was hopping someone would see this soon because I'm placing the order tomorrow night.

 

[pacecarta]

you could move the pedal pin down to correct the ratio of travel (lower will shorten the pedal travel) but will lessen the ratio so will require slightly more pedal pressure for same psi at pads ,
or change the master bore diameter , larger bore will move more fluid and result in less travel before pads seat but will require slightly more effort at the pedal for same psi at pads
or a little of both

have you tried adjusting the rear shoes out, the auto adjust on our drums only works if you apply brakes firmly when backing up

 

[Phoneguy]

If your drums have too much meat taken out of them they may not be contacting correctly. Look at the shoes to see the contact patch.

Bryan

 

[NY Twin Turbo]

you could move the pedal pin down to correct the ratio of travel (lower will shorten the pedal travel) but will lessen the ratio so will require slightly more pedal pressure for same psi at pads ,
or change the master bore diameter , larger bore will move more fluid and result in less travel before pads seat but will require slightly more effort at the pedal for same psi at pads
or a little of both

have you tried adjusting the rear shoes out, the auto adjust on our drums only works if you apply brakes firmly when backing up

I plan on relocating the pedal pin for sure if the new calipers don't get me all the way there. Also thinking of pre-loading the master cylinder by lengthening the rod and making a return stop. However, I really don't want to do this at all. Seems like a ghetto fix. I'm hopping the calipers get me real close or perfect.

One thing I know for sure........I'm not changing the master cylinder! NO WAY am I ever going to get another drop of brake fluid anywhere near my engine compartment or fenders again.

 

[NY Twin Turbo]

If your drums have too much meat taken out of them they may not be contacting correctly. Look at the shoes to see the contact patch.

Bryan

The drums are brand new and the rear brakes are adjusted properly. The residual valve is supposed to keep the rear brakes slightly up on pressure so they are there when you need them instantly. Also, because I run the biggies in the back and the skinnies in the front, I have full brake pressure to the rear because I can lock up my front tires on a hard stop from 30 MPH.

 

[NY Twin Turbo]

So, given my situation, what do you think? These calipers are the right ones to get me partially fixed up?

 

[Phoneguy]

Being adjusted properly is one thing , but I would want to be seeing the contact patch that the shoes are showing to be certain. If the shoes are hitting in the center only , they have to flex to make full contact which will give you the feeling of longer pedal travel. Just a thought

 

[NY Twin Turbo]

Being adjusted properly is one thing , but I would want to be seeing the contact patch that the shoes are showing to be certain. If the shoes are hitting in the center only , they have to flex to make full contact which will give you the feeling of longer pedal travel. Just a thought

And a good one at that. Maybe I'll pull a wheel and drum tomorrow to take a look.
But I did do a little test on the front. This is what I found. I had my better half sit in the car and press the pedal down while I spun the front wheel by hand. She was able to slowly depress the pedal almost an inch and a half before I could feel the drag on the rotor. Instantly after that, it stopped.

 

[NY Twin Turbo]

Seems like too much. No? And this is what I feel when I drive it. Once I go that distance with the pedal everything is fine. But it's that first 1.5 inches that's annoying the crap out of me.

 

[Phoneguy]

Definitely not right.
That would scare me enough to park it until I found the issue. Keep us posted
Good luck

Bryan

 

[NY Twin Turbo]

Definitely not right.
That would scare me enough to park it until I found the issue. Keep us posted
Good luck

Bryan

I plan on installing the calipers sometime soon this cold long winter ahead. I may be able to know the results just trying it at rest. But the car is down for various other "to-do" items until spring. So the test drive wont happen until then. But if this fixes the problem.....or even gets me close......I'll let you guys know.

 

[69RSCLONE]

Don't pre-load the master. If it doesn't fully release it will hold pressure on the fluid (I know that is what you want) but as it heats up and expands it will apply the brake as you drive. Just a heads up. Just had one of my customers have that problem and would start shaking on his way to work but only after 30 minutes of driving.

 

[NY Twin Turbo]

Don't pre-load the master. If it doesn't fully release it will hold pressure on the fluid (I know that is what you want) but as it heats up and expands it will apply the brake as you drive. Just a heads up. Just had one of my customers have that problem and would start shaking on his way to work but only after 30 minutes of driving.

No. I don't want to do this. As I stated earlier.......this seems like a ghetto fix. I'm going to keep up on my plan to change the calipers and then the pin location.

 

[turbobitt]

There are several unknowns that need to be answered as well as several compromises that need to be understood.

To make the system perform to its potential it is usually recommended to have a pedal ratio of 6.5-7 to 1. This is the pin position on the brake pedal. The master cylinder diameter is real important and needs to match the pedal ratio to give the best compromise between pedal effort and travel. I found that disk/drum combinations like 24mm(or 15/16") min diameter to about 1". Going larger will reduce the pedal travel but could increase the pedal feel to the point of being uncomfortable to drive. Even if you flat out refuse to change the master cylinder you should at least understand the size so that you can see where and how to make the changes to the pedal ratio to get where you want. It may also be impossible to get there with what you have.
I found this below link to be helpful.

http://markwilliams.com/braketech.aspx

AG.

 

[NY Twin Turbo]

There are several unknowns that need to be answered as well as several compromises that need to be understood.

To make the system perform to its potential it is usually recommended to have a pedal ratio of 6.5-7 to 1. This is the pin position on the brake pedal. The master cylinder diameter is real important and needs to match the pedal ratio to give the best compromise between pedal effort and travel. I found that disk/drum combinations like 24mm(or 15/16") min diameter to about 1". Going larger will reduce the pedal travel but could increase the pedal feel to the point of being uncomfortable to drive. Even if you flat out refuse to change the master cylinder you should at least understand the size so that you can see where and how to make the changes to the pedal ratio to get where you want. It may also be impossible to get there with what you have.
I found this below link to be helpful.

http://markwilliams.com/braketech.aspx

AG.

I'm going to check my records tonight for the exact size bore on that MC. Then I'll get back to you.

 

[NY Twin Turbo]

There are several unknowns that need to be answered as well as several compromises that need to be understood.

To make the system perform to its potential it is usually recommended to have a pedal ratio of 6.5-7 to 1. This is the pin position on the brake pedal. The master cylinder diameter is real important and needs to match the pedal ratio to give the best compromise between pedal effort and travel. I found that disk/drum combinations like 24mm(or 15/16") min diameter to about 1". Going larger will reduce the pedal travel but could increase the pedal feel to the point of being uncomfortable to drive. Even if you flat out refuse to change the master cylinder you should at least understand the size so that you can see where and how to make the changes to the pedal ratio to get where you want. It may also be impossible to get there with what you have.
I found this below link to be helpful.

http://markwilliams.com/braketech.aspx

AG.

I couldn't wait till tonight. I had my significant other pull the invoice out of the huge, tremendous, gigantic box of receipts for the Buick!

It's a 1 inch bore.

 

[turbobitt]

I couldn't wait till tonight. I had my significant other pull the invoice out of the huge, tremendous, gigantic box of receipts for the Buick!

It's a 1 inch bore.

That's sounds about right for a disk/drum setup. At least that is confirmed.
AG


Sent from my iPhone using Tapatalk

 

[NY Twin Turbo]

That's sounds about right for a disk/drum setup. At least that is confirmed.
AG


Sent from my iPhone using Tapatalk

Yes, and I'm using the factory location for the push rod pin. So, any ideas? It seems to me the next logical step is to change the calipers to non-low-drag.

Oh, and by the way, the rear brakes are making full contact with the drums.

 

[Boost231]

im running the 1.125" M/C on mine with no issues. i didnt install the piston sleeve so i do have about 1/8" travel before it starts to press on the piston.