"Drum to Disc" conversions 67-70 pics and videos
 

just want to start off by thanking Keith for putting together one hell of an amazing and detailed write up on this topic, I would just like to augment it from the end users perspective, following Keith's advice I will be converting what I think is a '69 six lug to a six lug disc setup, I would like to add some pics and videos

[my truck is registered as a 1971 GMC that's why I am not sure of the frame's origin]


DRUM TO DISC CONVERSIONS 67-70

67-70 truck with

67-70 Crossmember Installed:
1) There are many advantage to leaving your 67-70 crossmember in place to add disc brakes.

2) 67-70 truck owners can now purchase "year specific" standard and drop spindles, from many aftermarket suspension vendors.
* No need to change ball joints.
* No need to change tie rod ends.
* These new "conversion disc brake spindles" are a true "bolt-on" mod to add disc brakes to your truck.

3) The 67-70 a-arms can also be used with any other (71-72 or 73-87) spindle, with a simple ball joint change.
* The upper and lower ball joints and outer tie rods must match the correct year of spindle you choose.

4) You will need a "conversion" rubber brake hose to connect your disc brake caliper to your existing steel brake line.
* 71-72 rubber brake hoses can be adapted.
* Much longer 73-87 brake hoses can also be adapted.
* Aftermarket steel braided brake hoses are an option.

5) Keeping your original 67-70 crossmember allows to to leave the engine and transmission in place.
* No need to remove drivetrain.
* No need to temporarily support the engine, while removing the crossmember.
* Complete disassembly of the front suspension also allows you the ability to clean, inspect, replace or rebuild all the individual components.


Links:
*http://www.classicperform.com/discdrop.htm
*http://www.earlyclassic.com/Tech.asp...20That%20Truck
*http://www.customclassictrucks.com/t...all/index.html


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67-70 Truck With 6-lug Disc Brakes:

6-Lug Drum to 6-Lug Disc Conversions:
1) This 6-lug disc brake swap will include all of the above 5-lug information.

2) The only difference is the use of an aftermarket 6-lug rotor.
* These rotors are new castings.
* These rotors have been drilled with the correct 6x5.5" 6-lug pattern.
* These rotors have the correct 7/16" lug studs that match the original drum brake lug studs.

3) Several aftermarket suspension vendors sell these rotors,... such as:
* ECE (Early Classic Enterprises).
* POL (Performance OnLine).
* CPP (Classic Performance Products).

4) All 63-70 "conversion" stock height and drop spindles will work with these 6-lug rotors.

5) All 71-72 stock oem and drop spindles will work with these 6-lug rotors.

6) If using a 73-87 spindle,... it must be the HD spindle, that works with the 1-1/4" wide rotors.
* The 81-87 LD spindles will not work with these 6-lug rotors.

Links:
*http://www.earlyclassic.com/tech.asp...arly%20Braking
*http://www.earlyclassic.com/tech.asp...h%20And%20Whoa
* http://www.classictrucks.com/tech/05...all/index.html

6-lug Rotors:
*http://67-72chevytrucks.com/vboard/s...ght=Disc+Brake

Re: "Drum to Disc" conversions 67-70 pics and videos
 

so one of the first things I learned was that the drum spindles on my truck were two piece, the steering knuckle is a separate piece that bolts on to the actual spindle, I've been told some were one piece and some were like mine

I also believe the actual spindles are identical, in other words there is no right hand side spindle and a left hand side spindle, the same spindle the same part number can work on either side, if that is so that is absolutely brilliant engineering, but please correct me if I am wrong

I could not Google any info on that part number: 3944974 GM17

please let me know if I am misreading it

Re: "Drum to Disc" conversions 67-70 pics and videos
 

here is what all the jazz removed from one side looks like, bagged n tagged!

Re: "Drum to Disc" conversions 67-70 pics and videos
 

if you want to keep your alignment close to what it was, pay attention to these little shims that sit on top of the upper control arm rod

Re: "Drum to Disc" conversions 67-70 pics and videos
 

I will be using the 1971-72 disc brake spindles so the stock lower control arm ball joints need to come out

here I am using a control arm puller kit that you can rent from O'Reilly's (I think it costs $145 bucks but you get it back when you return it)

Re: "Drum to Disc" conversions 67-70 pics and videos
 

Great addition:metal:

Re: "Drum to Disc" conversions 67-70 pics and videos
 

and because I have trust issues, here I am trying that stock OEM lower control arm ball joint in the new 71-72 disc brake spindle, and as you can see it is too big to fit in there

Re: "Drum to Disc" conversions 67-70 pics and videos
 

thanks, just trying to help, and give back to the forum community, it has saved my _____ on too many occasions

Re: "Drum to Disc" conversions 67-70 pics and videos
 

if you never seen a lower control arm in the wild before here is what they look like and what holds them in place to the crossmember

yes they are dirty, they are covered in half a century of dirt, rust, and road grime

[I will be pressure washing mine, wire wheeling them, phosphoric acid washing them, and media blasting them as well, then DIY powder coating]

Re: "Drum to Disc" conversions 67-70 pics and videos
 

and this is what the upper control arms look like, can you spot the difference between these two?

Re: "Drum to Disc" conversions 67-70 pics and videos
 

the one on the left was original, the one on the right had it's ball joint replaced

how do we know that, well the factory rivetted them on, and the aftermarket ones are bolted on

we start off by removing the aftermarket ball joint, cause it is much easier to remove

Re: "Drum to Disc" conversions 67-70 pics and videos
 

Top Tip: when buying a truck look at the upper ball joints to see if they are stock, ie rivetted on or bolted on, ie replaced (it will make you look like you know what you are doing, ha ha) seriously though and this is going to be controversial, but the only reason farmers and construction workers back in the day would replace one of these was cause the truck was wrecked, trust me! they did not hot rod these trucks back then, they used them, these trucks built America after all

Re: "Drum to Disc" conversions 67-70 pics and videos
 

things get a bit more abrasive on the other side

Top Tip: if you want to grind metal quick use sand discs (the lower the grit the better, here I think I am using a 36 grit flop disc), them grind stone wheels are for Hollywood movies where they wanna make sparks ie special effects, [I'm looking at you Splash Dance]

Re: "Drum to Disc" conversions 67-70 pics and videos
 

hope you enjoy this video 1967-70 Chevy C10 Drum Brakes, Control Arms, Spindles, and Stuff

Re: "Drum to Disc" conversions 67-70 pics and videos
 

Great thread!

Re: "Drum to Disc" conversions 67-70 pics and videos
 

oh wow, thank you so much

Re: "Drum to Disc" conversions 67-70 pics and videos
 

now you aint gotta take the rod out of the upper control arm to complete the swap to disc brakes but if you come this far it could use some fresh rubber boots at least

a 1 and 3/8ths socket and a 9' breaker bar will git you started

and them ol' cylinder head bolts you've been holding on to for the last 6 years will finally pay off and come in quite handy when it comes from keeping that rod from spinetizing

Re: "Drum to Disc" conversions 67-70 pics and videos
 

and then you can finish the job with a wireless impact when nobody's lookin'

Fun Fact: PB Blaster works great at lubretizing them threads, ACE Hardware knock off, not so much!

and for what it is worth, having worked on five different generations of these trucks and SUVs I must say the GM Engineers knocked it out of the park on the second gen dimes, (67-72) awesome, awesome trucks!

Re: "Drum to Disc" conversions 67-70 pics and videos
 

if you get one of them 1-3/8ths sockets it may come in a large ratchet size, so you will need a smedium adapter, like so

it's a big sucker, so here's the natural progression to get you back to a 3/8ths, you're welcome

Re: "Drum to Disc" conversions 67-70 pics and videos
 

and here it be all extrapulated and such

Re: "Drum to Disc" conversions 67-70 pics and videos
 

I cleaned it up to see the part number, can someone let us know if they are both the same or is there an East and a West side rod?

Re: "Drum to Disc" conversions 67-70 pics and videos
 

I usually go the extra mile and bedazle all the sharp edges on the parts no one will ever see, it's a sure fire way to stretch a little weekend project into a couple months worth

Re: "Drum to Disc" conversions 67-70 pics and videos
 

and here's a little stare and compare of the two upper control arms, one has already been tickled a little with a wire wheel

Re: "Drum to Disc" conversions 67-70 pics and videos
 

your upper ball joints may be stuck in the spindles so tight you may need to cut them on the truck to get them off (I used an angle grinder and a sawsall) here I am pressing out the remaining tips out of the spindles just so I can try them on the new 71-72 spindles to see why we need new / different ones

you don't have to press the cut ends out of the spindles if you don't want to, these spindles are not going back on the truck

Re: "Drum to Disc" conversions 67-70 pics and videos
 

and here once again we are proving Keith was right, and the new 71-72 disc spindles will require new 71-72 like ball joints

the old 67-70 upper ball joints are also too big for the new 71-72 disc spindles

Re: "Drum to Disc" conversions 67-70 pics and videos
 

the lower control arms were next, for this you will need a socket that is always one size bigger than the biggest you got, ( aka 1-5/8" ) ha ha

don't be too proud to use a cheater bar, but do it when yer fishin' buddies aint lookin'

Top Tip: once you get a turn or two in and can see a row or two of threads, please spray it with some PB Blaster (no not WD-40 that ain't penetrating oil, nor cutting oil, don't get me started, ha ha) and then, SCREW IT BACK IN, say what? No way man, we worked too hard to get it out this far, trust me, screw it back in and she'll come out like a hot knife through butter.

Re: "Drum to Disc" conversions 67-70 pics and videos
 

getting one side of the lower control arm rod off is easy as it wants to use the control arm as leverage to keep it from spinning, the other side is a bit tricky, I found a small clamp fits nicely in the small dimple in the rod and wedges itself just enough against the control arm to keep the rod from spinning

Re: "Drum to Disc" conversions 67-70 pics and videos
 

and a few moans and groans later...

Note: one lower control arm already had a little date with the wire wheel

Re: "Drum to Disc" conversions 67-70 pics and videos
 

Good Enuff Garage:

Chevy C10 67-70 drum to 71-72 disc components

YouTube video

Re: "Drum to Disc" conversions 67-70 pics and videos
 

I first wire wheel the grime, rust, and dirt off of all the parts and then treat them to a power washer bath

Re: "Drum to Disc" conversions 67-70 pics and videos
 

then I media blasted them

Re: "Drum to Disc" conversions 67-70 pics and videos
 

I like all the detailed info on your control arm rebuild.

Since I only deal with lowered truck,… I like to trim a portion of the “gutter” as I call them.
Just 1” to 1-1/2” on each side of the lower balljoint hole.
This allows for a 15” wheel with up to 4” backspacing to be used with a drop spindle.
Not needed for stock spindles.
I know some say it’s not necessary, but they make 2”, 2.5”, and 3” drop spindles for these trucks.
And even if you’re running a bigger wheel, you never know when you might have to throw on a spare.

I trim the gutters and clean them up with a flap disc.
Don’t leave any sharp corners.
I really like to do this ON the truck so you can rotate the wheel back and forth to check clearances.

Great thread.
I didn’t mean to interrupt it.

Re: "Drum to Disc" conversions 67-70 pics and videos
 

thanks, and please interrupt away, it is OUR thread and just a small extension to all the heavy lifting you have done for all of us already

would you be be able to provide me a template or some measurements where I should weld back my steering stop on the lower control arms, I have a separate thread for that, but it's related, I learned someone ripped them off my lower control arms, and it may be a good idea to weld something back on, I just want to get it in the right place

Re: "Drum to Disc" conversions 67-70 pics and videos
 

I don’t really have any kind of template.
I never remove them entirely.
I cut off the taller “stand” that holds the rubber bump stop.
Then I just leave a portion of the steering stop for the spindle to contact.

Re: "Drum to Disc" conversions 67-70 pics and videos
 

progress not perfection

Re: "Drum to Disc" conversions 67-70 pics and videos
 

so I am getting a bit ahead of myself but I figure if I am going to document any of my research I might as well do it in public to share and help others, so here we go:

Fun Fact: You can drive yourself crazy shopping for ball joints for this conversion! How crazy is up to you, ha ha

case in point, in my imagination I was raised by a grandmother master mechanic who was a firm believer Made in the U.S.A. is better, she had Craftsman, MOOG, and ACDelco tattooed on the small of her back (I'll pause and let you recover from having to picture that) it would break her heart if we were to tell her MOOG is no longer solely made in the USA, but all over the darn world, and the quality varies accordingly!

so I start my research with MOOG upper control arm ball joints (don't wanna piss off grams)

• O'Reilly's: MOOG Part# K6124 (says it fits 1971) but costs $78 bucks

• AMAZON: MOOG Part# K6124 (says it does NOT fit 1971) but costs only $33 bucks

Re: "Drum to Disc" conversions 67-70 pics and videos
 

so let's meet our new 1971-72 disc brake spindles

Left hand side is part # 3969461

Right hand side is part # 3969462

Re: "Drum to Disc" conversions 67-70 pics and videos
 

I know what you is wondering: How much do these bad boys weigh?

Re: "Drum to Disc" conversions 67-70 pics and videos
 

so I was over at my used 67-72 truck parts suppliers barn the other day and we was just standing there staring at both a 67-70 crossmember and a 71-72 crossmember and the only difference we could spot was the extra brake line brackets on the front of the 71-72 crossmember for the disc brakes, is that the only difference

Joe does drum to disc brake conversions by unbolting the 67-70 crossmember with all the drum brake control arms and spindles on it, and just mounts a 71-72 crossmember with all it's disc brake control arms and spindles in it's place and it just bolts right up

I told him about lolife's (Keith's) write up and how he could just swap out the ball joints and tie rod ends

Re: "Drum to Disc" conversions 67-70 pics and videos
 

just stumbled on this OEM control arm bush listing on eBay and thought I would share

Part Number 3842882 GM NOS (New Old Stock)