rear disc brake idea

[k20]

i THINK all the prop valves are the same, however, I had already replaced mine when I was doing some other work on the truck so thats no longer stock on mine. This is the height sensing valve over the rear axle that I am referring to. I actually think its only trucks that have it, not the blazers.

 

[imiceman44]

Just a thought here, i haven't heard or seen anybody talking about them, but my '88 IROC had rear disk brakes that i am pretty sure used the same brake pad, was there some issue as to why these couldn't be used, spacing, bolt pattern or something?

I know the have e-brake levers too and don't use the drum in hat setup either.

The reason my friend is the same reason they don't use the 80's eldorado calipers, because they are meant for non vented rotors, so you can't put vented rotors from an IFS truck with those.
If you can find a 6 lug 5.5 pattern, or even an 8 lug pattern with non vented rotors, then you can do this.
Until that happens you will need the 76-78 eldo calipers.

 

[4xcrazy]

The reason my friend is the same reason they don't use the 80's eldorado calipers, because they are meant for non vented rotors, so you can't put vented rotors from an IFS truck with those.
If you can find a 6 lug 5.5 pattern, or even an 8 lug pattern with non vented rotors, then you can do this.
Until that happens you will need the 76-78 eldo calipers.

Not sure i'm following for some reason, tired from working out in the garage, but are you saying, the rear calipers from the Camaro i mentioned, only work with non vented rotors?
cause they are a vented rotor, i know there is a thickness difference between vented and non-vented, obviously the rotors from the car won't work, but that's not what i am referring to.

This is a rear rotor from a Camaro.

 

[imiceman44]

Not sure i'm following for some reason, tired from working out in the garage, but are you saying, the rear calipers from the Camaro i mentioned, only work with non vented rotors?
cause thay are a vented rotor, i know there is a thickness difference between vented and non-vented, obviously the rotors from the car won't work, but that's not what i am referring to.

This is a rear rotor from a Camaro.

Oh my bad, it looks like it might work.
Unless they are much thinner vented rotors.
The 84 caddy eldorado had non vented rotors that were 1/2" thick.
I did get them though because I am putting a set on my 70 5 lug chevy pickup and it will be fine with the rotors from the same car, it has the wide five lug same as half ton 2wd trucks.

 

[4xcrazy]

This is why i am curious, i realize the offset is not going to be the same as the front calipers we usually use now, but for the original design process, someone had to mock up and test fit different bends and spacing and whatnot before they figured out the correct measurements to be able to use a front truck rotor out back.

also,,,

Camaro Brake Rotor Thickness New : 1.04"
reference '89 Burb front rotor - Brake Rotor Thickness New : 1.29"

I really wouldn't think that would be enough of a difference to be a problem as far as rotor thickness.

 

[imiceman44]

This is why i am curious, i realize the offset is not going to be the same as the front calipers we usually use now, but for the original design process, someone had to mock up and test fit different bends and spacing and whatnot before they figured out the correct measurements to be able to use a front truck rotor out back.

also,,,

Brake Rotor Thickness New : 1.04"

Well I can't remember how much the IFS rotors are but I want to say a little more than that.
Also you want to see how thick the pads are for the IROC versus the 1/2 tons we use.
I am not sying to dismiss it but you need to do more investigating before we can make a judgement on that.
It's good to keep finding these things to give us more options.
I just started working on a kit to modify the pedals from a mechanical clutch bell to a hydraulic style.
And it won't cost much.
I also am working on a simpler design that is neither nor.

 

[4xcrazy]

not sure why you keep bringing up IFS stuff,,, unless you're using the letters to describe something other than Independant Front Suspension,,, I used the same front rotors on my Burb, for the rears.

But as far as these other calipers and brake pads, i just looked at the pads, they are alittle different in design, but still have an overall similar mounting setup that the front of the trucks use.

anyways, i'll get back with this later, i just may do some more investigating on this, getting measurements, pad thicknesses in person at the parts stores and whatnot.

Not that i really need them, i'm happy at the moment with my setup, just no e-brake..

 

[thatK30guy]

How about someone just post up some pics of the 2 different calipers side by side so we can view the differences between the so said piston sizes.

I'm still skeptical about this.

 

[thatK30guy]

I just checked O'Reilly site and they do list the 2 different numbers.

JD7 has 3 5/32" piston.
JD6 has 2 15/16" piston.

 

[bronc3buster842001]

Ill look tomm. and see if I have both sizes. I know i have the bigger ones.

 

[thatK30guy]

Is roughly 3/16" going to make that much difference in braking performance?

 

[imiceman44]

not sure why you keep bringing up IFS stuff,,, unless you're using the letters to describe something other than Independant Front Suspension,,, I used the same front rotors on my Burb, for the rears.

But as far as these other calipers and brake pads, i just looked at the pads, they are alittle different in design, but still have an overall similar mounting setup that the front of the trucks use.

anyways, i'll get back with this later, i just may do some more investigating on this, getting measurements, pad thicknesses in person at the parts stores and whatnot.

Not that i really need them, i'm happy at the moment with my setup, just no e-brake..

I don't know if other discs will work but I use the IFS front discs on the rear axles.
That is what my first TSM brake setup said and I have been using those since.

 

[imiceman44]

Is roughly 3/16" going to make that much difference in braking performance?

Yes.
That is about how much the 3/4 ton rotors are bigger as well and they DO make a difference.
Also look at it as a percentage, and it's quite a bit bigger.
3/16" is 6% bigger