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On a factory power brake car, can you move the rod to the top pedal hole to facilitate more brake pressure ?
my concern is that it will put the rod in a bind ?
anyone ever try this ?
If for some reason you think that you don't have enough brake pressure, I would look at the common issues these cars have, starting with 1) condion of the brake pads 2)leaking calipers 3) worn rotors 4)leaking rusty brake lines 5) bad vacuum line to booster 6) booster itself. Nwver heard of anyone trying to move the pin to fix weak brakes. Let us know what you find.
Thanks for your reply , and although you did not answer my question, I will try to answer yours.
I have an all " brand new " Wilwood system with Super Lite 6 Piston Fronts & 4 piston Rears , all brand new brake lines, no residual valve,
Brand new booster & three different brand new master cylinders.
The LS3 engine pulls 18 psi vacuum and the car will not lock up the tires front nor rear. I have changed the booster twice, the pads twice , It has been gravity bled, hand bled, pressure bled, Calipers have been stood up at 90* to remove all air and the car will not lock up the tires ?
The company that I purchased the system from, asked me to try moving the rod up to the manual brake position of the pedal to see how it responded.
My question was geared around the geometry of the rod placement when using the booster in the manual position etc.
Thanks
Originally Posted by kanvasman
If for some reason you think that you don't have enough brake pressure, I would look at the common issues these cars have, starting with 1) condion of the brake pads 2)leaking calipers 3) worn rotors 4)leaking rusty brake lines 5) bad vacuum line to booster 6) booster itself. Nwver heard of anyone trying to move the pin to fix weak brakes. Let us know what you find.
You can try going from one hole to the other but I'll guess that won't work.
GM would not have two different holes if one was all they needed.
Manual master cylinders have a 1-inch bore and power M/C's have a 1 and 1/8 inch bore, do you have the correct one?
Also, the hole at the back of the M/C can be shallow or deep, do you remember which one came on your original?
The rod that goes into the M/C should be just flush, not too far back and not applying and pressure with the brake pedal at rest. Is that adjusted correctly?
You didn't state what size the bore was on the Master....
If you go with a larger diameter bore, it will INCREASE the amount of pedal effort required and require a shorter stroke; a smaller bore will DECREASE the pedal effort, but require a longer stroke.
The STOCK power brakes use a 1 1/8" and the non-power is 1"...I'd be looking at the Master cylinder size first..
On a factory power brake car, can you move the rod to the top pedal hole to facilitate more brake pressure ?
my concern is that it will put the rod in a bind ?
anyone ever try this ?
You will have more mechanical advantage with the rod in the higher hole, but the pedal will have to travel farther to get the same movement to the rod. So, yes, you will be able to apply more pressure to the brakes with a given pedal pressure, until the pedal contacts the floor, of course if that happens braking will be compromised. I don't think it will bind the rod, but I have not tried it.
Everything above is making me point towards the Master Cylinder - Booster - Brake Rod and by the amount of parts You have it sounds as though You have been switching a lot of parts. The Parts You are using are very popular with the users of this sight so there should be a solution to be had. Who's Booster ? What Master Cylinder's ? When the Brake Peddle is all the way down is the Master Cylinder bottomed out or is the Brake Peddle running out of travel ? I would want to put a Pressure Gauge in line and see what your getting. Since the Brakes them selves are Willwoods a call to them if you havn't all ready might solve this.
Your profile shows you own the following year cars: 65 66 67 99 08.
So what year C3 do you have?
What is the part number of the master cylinder you are using?
You didn't state what size the bore was on the Master....
If you go with a larger diameter bore, it will INCREASE the amount of pedal effort required and require a shorter stroke; a smaller bore will DECREASE the pedal effort, but require a longer stroke.
The STOCK power brakes use a 1 1/8" and the non-power is 1"...I'd be looking at the Master cylinder size first..
Richard
I'd check the bore size first.
I switched from a vacuum boost to HydroBoost years ago. Have you considered that modification?
I've been waiting for my Wilwood kit since early February. I'll be watching this thread to see what you how you figure our the problem and solution.
To answer my own question, NO, you can move the rod to the top hole in the peddle with the use of the booster.
The geometry with the booster is a bit different than if you mount the master directly to the firewall.
So , I eliminated the booster altogether and proved that the vacuum was not the issue as I still can't lock up the tires.
I have installed a 7/8" bore master with no luck or better results.
I have tried them all now... 1 1/8", 1 1/32", 1" , & now a 7/8" & two different brands....
I am now going to my third different set of pads, This time I will try Hawk HP+
I will keep you posted on what I find
There is no brake pad made that can't lock up the tires. Since You have tried every bore size made do they perform differently ? When the Brake Peddle is all the way down is the Master Cylinder bottomed out ?
Looks like it was as much a brake pad issue as anything.
switched brands , Went to a Hawk HP Plus pad and the car stops GREAT....
Never would have thought that the pads could make that much of a difference , but it did on my car ....
Thanks Hawk !
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
Your question on the holes in the peddle. As per the aim pictured in post #5
, the top hole is manual and the bottom is power and other threads have mentioned the ability to switch for performance. Glad you fixed it
Last edited by Rescue Rogers; 04-19-2016 at 07:36 PM.
Please know that Poly H is a serious racing compound and really has no purpose on the street. It's will not be suited to low temp applications and promote faster rotor wear as well as excessive dusting.
Get it up to 1000f and it'll be right at home tho.
04-07-2016, 04:39 PM
Odd Brake question
I'd check the bore size first.
