Rear dics brakes??

[454_72_4X4]

I would like to put rear disc brakes on my 72.
Thought maybe some of you guys could provide me with some answers.

First my truck specs;
72 3/4 ton 4X4
Mid 70's Corp 14 bolt rearend

Has anybody already done this swap?
I've looked at some of the "kits" and I just think they are WAY overpriced.

I've already got a set of front discs and backing plates.
The kits I've seen have a spacer between the axle flange and the disc backing plate.
Any ideas on the dimensions ot the spacer?

Parking brake will be a hydo-lock so that's no concern.

Also I have an aluminum mastercylinder off of a mid 70's truck on my 72, (with a late 70's Monte Carlo power booster!).
I know there's a residual, (not sure about the spelling!), presssure valve in all brake systems and that a drum brake system requires one with more pressure than the disc brake system does.
My question; whereis it located and how would a person go about changing it?
Any other things to look into about this swap?
Thanks!

[Mudder]

I will get you the size of the spacer. The holes have to be redrilled in the backing plate and a small notch cut in it, otherwise its everything from the front axle (dana 44). Give me a few days. Friend is a machinest, so Ill have to get it to him.

[drink2mny]

I have spacers for sale already made to work with the stock backing plate( front 3/4 ton chevy 4x4 front backing plate)
I could do 90.00 Plus S&H to your door

Again these are not what Blackbird's sells ( i run the website in my sig) These came off customers trucks..

Here is the original thread
http://67-72chevytrucks.net/vboard/s...threadid=96603

[454_72_4X4]

Cool, Thanks Mudder!
Does/can your machinest frien make the spacers?
If so I might be interested in haveing him make a set.

BTW, Where are you from in MO? I'm in the northeast corner, (Kahoka if you know where that's at!)

[454_72_4X4]

Hey drink2mny,
I've never seen those kind of spacers. Seems like an easy way to go about it.
I'll see what comes up and maybe get back with you about them. I'm assuming that's $90 a pair?
Just asking, but why won't you give the dimensions?

Couple otherquestions while I'm here.
Is there any modifications that have to be made to the discs or the rear hubs, (after you remove the drums), to put the discs on the rear hubs?
Also what wheel studs do you use? Original, (only new), front or rear studs work?

[drink2mny]

Yeah the price is for the pair

As for dimensions, one I work for Blackbird's Custom Trucks (Rear Disc Brake builder) I could give out dimensions for the 14 bolt I suppose. But once i did that, it would stop people from asking all the time as to what dimensions are for our other kits, them what rotors and so on and so forth..

If people search the internet they can get the dimesions for the 14 bolt rear disc kit pretty easy. I just don't need the hassle of someone calling up Randy( the owner) and saying you goy a guy online posting dimensions for your kits..

I hope you see where I'm coming from.. But go man go for info from the other guys on here. Lot of them have done the setup you are looking to do...Including Mudder67.

These spacers where originally from a kit that ORU first made about 4 years ago to work with the existing backing platse and rotors.. we had a couple customers that didn't like them so swapped for our type of kits..Don't really remember the details why..

As for your question with the lugs you can reuse your olds but recomend new lugs no size change in them..

No mods to the hub, some backing plates have a small tab on them that needs to be persuaded(love tapped by hammer) flat..

Hope this helps and explains why I personally can't give out dimensions..

[Big J]

Not sure how much you want to spend but check these guys out. They're stuff looks awesome.
http://www.stainlesssteelbrakes.com/

[drink2mny]

Originally posted by Big J
Not sure how much you want to spend but check these guys out. They're stuff looks awesome.
http://www.stainlesssteelbrakes.com/

No 1 ton 14 bolt kit

[s95930]

Does anyone have any pictures of this modifcation?

[454_72_4X4]

I can understand where you're coming from. Makes sense.
Thanks for the info.
At least Blackbird's kits are quite a bit more reasonablely priced than the others I've seen.

Right now I'm working on a transmission deal and $ are somewhat tight. Otherwise I'd just buy your adapters and make my life a little easier.
Never know, I might get a lucky lotto ticket or something!!
I'll keep you in mind.

[454_72_4X4]

s95930
If I can gather up the rest of the parts I need I will take some pics but it might be awhile.

Just thought of more questions, (full of them ain't I!!);
What about the small rubber brake hoses that go from the axle housing to the caliper? What/where do I use? Since I use stainless braided on all the rest of the truck can I get some stainless braided lines for these too?

[drink2mny]

Originally posted by 454_72_4X4
At least Blackbird's kits are quite a bit more reasonablely priced than the others I've seen.

I'll keep you in mind.

We strive to be the best prices out there, thank you for the compliment..

I do have 2 sets of the spacers so no worries, if ya do .. Ya do.. If ya don't.. Ya don't..

Good luck with this..


Here is what it might look like.
This is Mudder67 setup

[Mudder]

I will call calvin in the morning and see what I can get ya a set of spacers for. I think he had extras made up.

[Autometer]

Originally posted by 454_72_4X4
Also I have an aluminum mastercylinder off of a mid 70's truck on my 72, (with a late 70's Monte Carlo power booster!).
I know there's a residual, (not sure about the spelling!), presssure valve in all brake systems and that a drum brake system requires one with more pressure than the disc brake system does.
My question; whereis it located and how would a person go about changing it?
Any other things to look into about this swap?
Thanks!

You may want to look into getting a master cylinder off a car that had 4 wheel discs. It has a large capacity for the rear. When I put rear discs on my Malibu, I used a master cylinder for a '78 Saville. The old one would give me a low pedal.

[Mudder]

I can get them for 70 bucks and shipping which shouldn't be that much.

[69k5]

you can buy the spacers that some of the kits use at home depot. basically a nut with no threads for like 1.00 apiece. i cant tell you the exact dimensions b/c I have an eaton rearend. somewhere in the 3/4 to 1" range iirc. although the solid spacers would make me feel better. my kit has two steel rings cut and stacked. from the same 3/8 plate that made the bracket. i gueess that would make it 3/4" spacer huh.

69k5

[454_72_4X4]

my kit has two steel rings cut and stacked. from the same 3/8 plate that made the bracket. i gueess that would make it 3/4" spacer huh.

That's the type of answer I've been looking for. Thanks 69k5!
Now if yours was just a 14 bolt instead of an Eaton...

Mudder67, Those look nice. And the price is getting better!
If $ weren't so tight this time of year for me I'd buy those.
Could you tell me how thick they are?
I'd kinda like to have something like 69k5 was talking about, (steel), but one piece instead of the two rings.
Aluminum just makes me a bit nervous.

Autometer,
That's a good idea. I'll have to look into that.
Anybody have an idea what mastercylinder would fit and work?
If you used one off of a Seville on a Malibu then the same thing might work for me cause I have the Monte Carlo booster already on there. What year was your Malibu? If I remember right my Monte booster is off of a 78 or 79.

I think that would solve the residual, (spelling again?), pressure valve problem too because I think it's in the mastercylinder.

I'm getting closer!
Anybody need a good set of drums?!

[69k5]

corvette would be the easiest. also the 14 bolt and eaton are the same kit. the only diffrenece if there is one is the spacer. you could get 3/4 and 1" and see which made it right for you.

69k5

[1972C10]

So is the 4x4 backer plate held down with 6 bolts or 4? Im not getting the 6 holes in the spacers at the top and then ther others not having them.

Does the disc swap retain the same prop valve?

[454_72_4X4]

The factory front backing plate is held on with 6 bolts.
The factory rear backing plate is held on with 4 bolts.
You have to redrill the holes in the front backing plate to match the 4 hole pattern on the axle tube for the spacers with just 4 holes.
I was planning on using one of the adjustable prop valves myself. I don't think the drum brake prop valve would work very good.

[trukman1]

Tell ya all what...Give me a day or two to get in touch with my buddy who is a machinist...I gave him the drawings for the spacer for the 14-bolt with front backing plate and I'm sure he still has it. If i remember correctly, it was alot thicker than I originally thought. I switched modes of thought and bought the plans for the 3/8" plate and 3/4" spacers off ebay for $5 + $3.50 S/H. Scanner and digital camera both quit working recently so I'll only be able to provide dimensions, not photos. BTW, I'm running virtually the same truck combo with a D60 and swapped to the hydoboost system. My friends are running this system with the stock M/C and proportioning valve and rear discs and they all say it works just fine as is. I'll report when I get mine on. Also, one guy has hydro-lock and it works as a park brake but the cops don't count it as an emergency brake here in OH (ask how he knows). Will try to get info here tomorrow. Bye!

[drink2mny]

The factory front backing plate is held on with 6 bolts

That is why the spacers I have for sale work with a stock backing plate..
No redrilling.

the 4 holes already there to bolt to the flange.. and the six holes already for the backing plate from the front..

And i have to retract what I was told about those spacers..

Those were not from a company selling kits. those were made from a local mud racer and just didn't want them anymore..

Sorry about that..

[454_72_4X4]

Hey there trukman, Did ya come up with anything yet?

Shot in the dark here;
If the 3/8 plate bracket version uses 3/4 in spacers all I should need to do is measure the depth of the "dish" on the factory backing plate and add that measurement to the 3/4 to come up with the spacer thickness I'll need.
Would that work?

I'm going out to measure my backing plates right now!