Technical Under floor brake pedal instal?

My understanding too 31Vicky, you will also find some factory fitted pedals have a stop on them just before they hit the floor or firewall and the setting stops the MC piston or pistons completely bottoming out in cylinder should there be a situation it might........all bleeders open or both front & rear lines open circuited .

 

I'm very old school on a lot of tooling myself.

Actually, I can change ratios, scale sizes, and do MANY changes with no more than 1 or two clicks of a button on a keyboard. Just to give you an idea of how easy it is, mcmopar had posted up a picture of 2 different brake pedals, hand drawn, bare measurements and not 100% to scale. In under 5 minutes, I had programmed his 9.5" pedal, and his 11.5" pedal. He wanted a 4.5:1 ratio, but his measurement would have been 4.6:1 ratio. Since I'm a bit anal about math (OCD sucks) I programmed it both as a 4.5:1 as his 11.5 pedal AND a shortened 11.25" pedal as to not change the 11.5" if he wanted. Thats about 5 minutes for 4 variations. Soooooo, I guess it just depends on the part we are programming. 2D programming is easy, 3d can be MUCH harder.

I often get guys snail mailing or scanning/email their patterns to me. Hell, Ive had guy scribble with crayon and just supply me with key measurements. Here are the 4 pedals to show you how simple it really is.

 

Just to tell you what I can do off a drawing. There is a tattoo artist here in town. Great artist, drew up this cartoon looking drawing of a 31 Ford pickup. Obviously nowhere near scale. I took his drawing, took some measurements, blended the two, tweeked it here and there and ended up with a REALLY off the wall cartoon looking frame. I didnt post up pics, because it is no where near traditional.

 

because it is no where near traditional.

But man was it cool !!!

 

I was going to cut them out by hand, then I saw prewars cnc plasma, and knew it was a time saver. I will still cut parts out by hand, but not all. Thanks Mike
I have not heard about the bottoming of the brake pedal. I will read the directions, when I get my m/c. The bore on the m/c I wanted is 1 1/8" bore, and a Jags is 15/16. I don't want to sleeve it, and not sure how big of difference it will make. I have read the pressure differences but how will they affect my foot and brakes? Will I blow out seals, or will it just feel off?

 

Finally got my pedals mounted, and now more questions. The booster will be 18" away from the pedal, and the rod will have about a 1/2" rise to it. Will this be a problem? I can change it, but then it puts the booster closer to the ground. Is there anything else that you see wrong in the pictures? Just tacked in for now, so changing things is easy.

 

At that distance ( 16" to 24") I'd use minimum 1/2" thick wall rod. I would be OK with 1/2" rise over that distance (18") as the stroke would be close enough to being on line with the bore centreline. If possible, adjust booster slightly to ensure a straight push.
Also consider a simple return spring at the M/C booster end.

 

You want the input to the booster to be as straight as possible. I would angle the booster to eliminate/minimize any angle between the long pedal push rod and booster input rod.
I would strongly recommend adding a bushing or bearing support at the end of the new push rod, very close to the new junction, to prevent the factory booster rod from being forced out of alignment and damaging the booster control valve or binding.

 

I've been working in a setup for my 29 Chevy. I got a pair of 1946 Chevy truck pedals. I plan on converting the break pedal to a push style pedal. The original setup is a pull and bell crank.

But I want my setup to be more line a 1949-1959 truck pedal, AD or TF. Because I will be running brakes from a 1959 truck.

Does anybody know what the angle is between the part above the pivot point, and the one below? Ratio on a stock non power brake drum-master single circuit, and is dual master a straight swap?

And does any of you have the mounting flange pattern, and hole size for the bolt holes and centerhole?

 

I will play with it a little more. I like the spring idea, where do you get one of them?

 

An old bonnet striker or similar spring

 

Any ideas for a source of a bellows at the master cylinder, as shown in the pic posted by "mgtstumpy" on the red car in post #67 ?

Looking for something to keep the dirt out of the master cylinder.

Thanks for any ideas

Canuck

 

Be careful when using a compression return spring, because you don't want the spring to bind and limit pedal travel.

 

what the hell is a "bonnet striker"? Oh, hood latch spring! got you.

 

That spring is pretty slick,
In that configuration it's working on the inverse of the pedal ratio- the pedal weight x ratio.

It's a hell of a lot Better than this

 

Looked at a lot of different springs for mine, ended up with the following for a return spring

:

Return spring – 89 – 94 Caddy Fleetwood hood ID=1.375,OD=1.655,Length=3.575,Min length=2.768,Wire=.135,22lb/inch

Fits over the neck on the master cylinder and against a washer with a lip to keep it in place on the pushrod.

Still wondering what to use for a suitable bellows to keep the dirt out??

Canuck

 

Was that really the way it was? Some people really amaze me when they are trying to fix things.

 

1/2" over 18" is fine. On a spring, just make sure it also doesnt push the rod out of the hole by using stops.

Pedals look good in there.

 

I got my booster and m/c mounted last night, then noticed that the m/c was leaning down towards the passenger side of the truck by about a 1/4 inch, I thought it should be level. Went out this morning to cut my mount off and redo it, but it is level and where it should be. Upon further inspection, I found that the problem is in the mounting bolts of the booster. Is this normal, or do I have a screwed up booster? Are they designed this way for air to get to the top? In these pictures the 4 mounting bolts are level, and the m/c bolts are not.

 

It's up to you if you want to cut off the bracket to level it.

Many factory masters are tilted front or back without an issue, so a tilt to one side will also work fine.


or....Can you elongate the holes in your welded bracket, to rotate the booster a bit?

 

Yes, I can elongate the holes, but I prefer not to. I am wondering if this is normal, or if the booster was made wrong?

 

Will I break something in the booster if I bolt it down and rotate half of it to get the m/c sitting level?

 

Most likely it will split the membrane like a condom on "load". Your call if it is worth the risk, or you can live with slanted master.

If it drives you crazy, fix it of swap it.

 

That's the way to assemble and disassemble the booster. It's possible to rotate it, it's possible that it's over or under rotated out of the box

 

What I did was similar except that a smaller diameter spring and two different size washers are all inside the original boot (bellows). The larger washer butts up against the MC and the smaller washer butts up against the small end of the boot. In
my case the small end of the boot is touching the jam nut on the heim joint which acts as a stop. I used a stainless push rod and washers so that the push rod chafing on the large washer won't leave metal filings in the MC bore opening that will rust.

It's simple, works well and is totally hidden.

 

I agree on that there is two parts of the housing, and between them there is a rubber part. And it should be possible to separate the two parts and put them back together.
It can end up as you want it to be, or with a leek.
And they are put together in to half over the rubber. So fare, so good.

But with a lot of muscle just moving/turning it to the right position, will most likely cause the rubber to break/shear.
80-20 is the best odds, and that's against you.

But separating the two half is 50/40/10 being success/small leak/failure.

I know how little it take to damage the rubber in an actuator for air brakes (large trucks), but what you are asking I never seen done. But I think very few people have.

I'm not saying this to undermine you, just bringing my experians to the table. We might be in agreement about this, and I just might have misread you post.

 

If the booster was recently put together, I don't think you'd have one iota of trouble rotating it. It was rotated into position during assembly-right.

If the booster was older and used and saw many underhood heat cycles you are likely to damage the seal.

 

It is a new 8 "dual diaphragm booster.

 

I got everything mounted and level and am happy with it. I took a chance and rotated the booster, let you know how it turns out when I finish the brake system. It was a productive couple days in the garage. Brake and clutch pedal mounted. Tranny mount done. This is the first time in 2 1/2 years that the motor and tranny is in the truck with no wooden blocks holding it up. I can officially push the truck around, THANKS H.A.M.B.