DIY Disc Brake Conversion

[mechanixman]

I've been looking at the disc brake conversion kits that cpp make. they're nice and all, but I've found a couple problems with them:
1. They don't make kits for the 1 ton trucks
2. At $375 for the 6 lug kit, it's WAY out of my price range.

It seems to me like the only thing you can't get at a junkyard is the bracket that holds the caliper. I know I can make that on the plasma cutter at school, so I'm not too worried about that.

What I'm wondering, is what holds the brake disc on the spindle?

[yossarian19]

Two ways to go about it.
1, find a rotor that fits around the hub. This is what CPP does, I think, and what most modern brake systems do.
2, put the studs through the rotor and then into the hub, press to fit. This makes a single piece hub-rotor, if I recall correctly a rear wheel drive Astro is set up about the same.
If you go with option one, which will be easier, you just bolt the wheel up to the hub & the rotor gets sandwiched. It won't go anywhere - but you DO want it to be centered on the hub, so a machined spacer ring may be needed.
EDIT: Also, lots of companies make hub-centric rings to adapt lug centric wheels. You may be able to find some in the right size to center the rotor.

[65Ch3v3LL3]

I would take the front hub off and take it into your local parts store and see if they will pull some 8 lug rotors until you find something that will work. One guy that did it on the 1 tons used a Ford van rotor I believe. Building the bracket for the caliper should be pretty easy.

[_Ogre]

all the repop stuff is for 1/2 ton trucks, but that shouldn't stop you
unbolt the backing plate, finding a disk that will fit you spindle will be your biggest problem
get a caliper that fits the disk application and make these



these are the adapters for a 1/2 ton truck, just adapt them to your application




read this http://static.speedwaymotors.com/pdf/910-31916.pdf

no brain surgery here, just take your time
google and look at lot of pictures

[_Ogre]

just ideas



rear but another bracket



ford truck with king pins



your stock wheels won't fit
you'll also need to update your mc to a disk/drum application

[mechanixman]

I've already got the master cylinder and brake booster, now I just need the prop valve.
Thanks Ogre, I found that page about 5 min after I started the thread.
I can't say I've ever seen a caliper with a huge spring and lever like that. Is it anything special? Or do bigger calipers just have that set up. It almost looks like it's mechanical..

You don't think the wheels will fit even if I find a chevy rotor?
If it won't fit, do they make steelies that hold the original chevrolet hubcaps?

[mknittle]

Check rotors for four wheel drives, they may be more likely to be two piece Hub and rotor. I know dodge and Chevy are the same bolt pattern. I think Ford is too but don't know for sure.
If you can't find something with the right center hole look for one with a smaller one and have a machine shop turn it to size.

[Trekster]

This is what I did on my 1 ton. I removed the drum and backing plate and bolted a 1978 Chevy 4x4 rotor to the hub. I used a caliper from a 1978 4x4 and built a bracket for the caliper.

[sqrlnts]

Originally Posted by mechanixman

I can't say I've ever seen a caliper with a huge spring and lever like that. Is it anything special? Or do bigger calipers just have that set up. It almost looks like it's mechanical..

I believe that is a parking brake setup.....

[lmdangerous]

I used the ford rotors on the front to avoid any machine work.( used the sleeves on each stud to center the rotor - along with the bigger studs). The calipers are the 3/4 ton 4 wheel drive units,( one all 4 corners.) but mine is a 3800 pick-up not a dually. Blackbird Enterprises makes a bracket to put the calipers on the back cheaper than you can build them. I cut the bottom corner off so I could slip it over the back axle tube and bolt it on - sorry I didnt want to take the rearend apart.rear disc goes on just like you said . yep you can even use the stock studs - they will work - even long enough to engauge all the threads into the nuts.( you could put a longer set in if you just have to have 2 inchs sticking out.
I use the speed way 1/2 ton bracket as a pattern to make my front caliper brackets. I am actually using the l88 vette manual Dual MC - no booster - and a pair of 2 lb residual valves -and adjuster from speedway. It will put your nose on the dash with very little pedal pressure.(I have several photos bracket , front , and rear I can text you or email you) - I also have the entire part number list that I used at napa.
Give me a ring if you need 662 542 0796. Someone does offer a kit for the 1 ton. -You do - The reason I did mine was the very fact that everyone said it could not be done for a reasonable price.(wrecking yard could make it dirt cheap -but with gas at these prices -can't run around and look much). Also nothing like having the old 3800 look good -different -and stop safely.

LMD

[lmdangerous]

When I say machine work - I meant I wanted the rotor to sit on the hub without having to turn either the rotor( inside the hat ) or the hub down ( outside circumfrence) .LMD

[mknittle]

Originally Posted by sqrlnts

I believe that is a parking brake setup.....

Yeap. that's what it is rear calipers have mechanical parking brakes.

[lmdangerous]

Nick,
For the record the backing plate bolt pattern for the 1/2,3/4, and 1 ton are all the same . Reason I used the speedway brackets as a pattern. Yea I know an expensive pattern. I thought the 1/2 ton bracket would work - and it would have but it wasn't far enough from the spindle center line to clear the rotor and mount the calipers.The 3/4 ton caliper is also a little bigger and the space between the caliper bolts is a little bigger. I also used two 3/8 thick plates over lapped to get ride of all the spacers. LMD

[OrrieG]

Originally Posted by lmdangerous

The reason I did mine was the very fact that everyone said it could not be done for a reasonable price.(wrecking yard could make it dirt cheap -but with gas at these prices -can't run around and look much).

We are cut from the same cloth! Thanks for posting without expectations of financial gain...

[lmdangerous]

Other Napa Parts:
# 38059 brake line for the front( right )
# 38061 brake line for the front ( left)
#82699 banjo bolt - need one for each caliper-
# TS- 728A-M - all four wheels. ( pads)

# 36846 the flexible rear brake lines ( yes even on the back they have to flex and move ) -One per side.
#36799 is the flexible line from the hard line to the rearend.
#641-3207 are the larger studs - for the front - drilled the hub and after install I spot welded each one - you could have just installed longer stock studs and used thin spacing sleeves on each stud - this centers the rotor - ( make sure that the spacers are no thicker than the rotor itself ) - still wound up using thin sleeves in the end even with the bigger studs . My reason for this was
# 1 there is no way it could not be centered - between the spacers and the tightning between the the wheel -( hole on the ford rotor is bigger )
The chevy rotor ( 3/4 ton 4 wheel drive rotor that is used on the back) - won't work on the front with out turning the hubs down - Don't leave much meat to hold the studs.
#2 Even though I have a mill/ lathe etc- This could be done without any of that- I even roughed the 3/8 plate out with a torch- then cleaned them up in the mill. Could be done with a grinder if it had to be.
Hope this helps - and if you need the photos let me know and Ill email them or text.
Oh yea dont for get the steering cross link needs to be shortened / adjusted at least 1 1/4 inches to be even close - then go to the front end shop and have the toe in /out set - I was still off almost 3/4 of an inch - And I swore I had it dead on Lol.

[lmdangerous]

Other Napa Parts:
# 38059 brake line for the front( right )
# 38061 brake line for the front ( left)
#82699 banjo bolt - need one for each caliper-
# TS- 728A-M - all four wheels.

# 36846 the flexible rear brake lines ( yes even on the back they have to flex and move ) -One per side.
#36799 is the flexible line from the hard line to the rearend.
#641-3207 are the larger studs - for the front - drilled the hub and after install I spot welded each one - you could have just installed longer stock studs and used thin spacing sleeves on each stud - this centers the rotor - ( make sure that the spacers are no thicker than the rotor itself ) - still wound up using thin sleeves in the end even with the bigger studs . My reason for this was
# 1 there is no way it could not be centered - between the spacers and thightening between the the wheel -( hole on the for drotor is bigger )
The chevy rotor ( 3/4 ton 4 wheel drive rotor that is used on the back) - won't work on the front with out turning the hubs down - Don't leave much meat to hold the studs.
#2 even though Have a mill/ lathe etc- This could be done without any of that- I even roughed the 3/8 plate out with a torch- then cleaned them up in the mill. Could be done with a grinder if it had to be.
hope this helps - and if you need the photos let me know and ill email them or text.
Oh yea dont for get the steering cross link needs to be shortened / adjusted at least 1 1/4 inches to be even close - then go to the front end shop and have the toe in /out set - I was still off almost 3/4 of an inch - And I swore I had it dead on Lol.

[lmdangerous]

Guys I have no idea why the post is here twice with several min. in between- I must of hit the enter button twice. still can't explain the time difference - Wait I was working on the time machine again - opps the government will be paying me a visit for sure now !lol

[mknittle]

Originally Posted by lmdangerous

Guys I have no idea why the post is here twice with several min. in between- I must of hit the enter button twice. still can't explain the time difference - Wait I was working on the time machine again - opps the government will be paying me a visit for sure now !lol

The same thing happened to me just a little while ago.

[OrrieG]

If you get that time machine working I need a trip back to 2005 to take care of some business...

[mechanixman]

Alright.
Well thanks for the advice so far,
I'm at the point where I'm ready to make the swap.
I've just hit one minor obstacle is getting the drum off the hub.
I know people have said it's just two rivets, and you can easily hammer them apart, but I think someone replaced them with screws on mine?
I don't know. What do you guy think/suggest?

[mr48chev]

Sure is nice when a guy posts high resolution photos that you can save and then expand to see what is going on.

I'd say that you are correct and someone has at one time replaced the drum and used two screws to hold the drum in place which wasn't the least bit necessary. They were riveted on the first time so they wouldn't fall off during transportation of the axle assembly.

If you have an impact screwdriver see if you can back them out. If not drill them out so you can pop the heads off and get the drum, off. It looks like you are going to want to knock the studs out and take the tin shield off the back too while you are at it.

Thinking about it the rear drums on my 71 3/4 ton GMC are held on by countersunk screws from the factory. That one is getting a disk brake conversion with brackets purchased on ebay and Chev 3/4 ton 4x4 front rotors with late 70's Cadillac Eldorado rear calipers with the park brake setup on them.

[mechanixman]

Thanks for the compliment.
I like to see other people's pictures, I figured I'd make the best picture I can. For some reason, my camera just wouldn't focus for the first picture.

How'd you come to choose eldo calipers? Is there any reason for those over stock 4x4 calipers or even some 6 piston of a late model vette?

[_Ogre]

single or double piston calipers will work fine unless your planning on course racing it
most 6 and 8 piston calipers are 1) expensive and 2) strictly for show

[mechanixman]

Well thank you all for the responses.

Imdanderous, I went to Oreilly's, just to see which rotor would work better, and the ford rotor seems to sit awfully far back. Now while that's good for caliper clearance, I'm afraid it will make the caliper mounting bracket more difficult then I care to make it.

I too felt that turning it down was unsafe, so I opted to use one of the mills at our school. First picture is our 3D modeling software. I just made a model of the outside, because that's all I'm worried about. Then the next 2 pictures are of the renderings of how the mill will cut everything out. and last 2 is of the mill working on the first hub. We're having problems making sure the hub is perfectly lined up, but I think I have a solution for that. At least one of the hubs will guaranteed be done by next friday.

[lmdangerous]

When I lined up the rotor I simply took the lug nuts and tightened them up with a Impact wrench.( the tapered lug nuts centered the rotor - Magnetic dial indicator was well with in spec.) I didn't figure that there would be a need to be much more accurate than that. I also got around the deep rotor by using the overlapping caliper bracket ( look at the pics I sent you- close)that set it back far enough that I didn't have to use a bunch of spacers and junk on the brackets where it bolts to the spindle.I figured that would be the weakest place and show the greatest load.
If I had your skills and access to those kinda machines I would have done the same. Your ideas are dead on, and in the end more accurate. You also can reproduce the info so that it could be applied to any machine in the country.Making this only easier for the next guy that wants to do this. Its gonna be good -and I just like the way that the stock front and rear axles look-Carry on Brother - Carry on-