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Old 01-17-2011, 06:10 PM   #4
lolife99
Old Trucks and a BelAir
 
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Join Date: Nov 2002
Location: Mid-MO
Posts: 19,810
"Drum to Disc" conversions 67-70

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

71-72 Crossmember Installed:
1) Your truck's donor 71-72 crossmember came from the factory with disc brakes.

2) "Year Specific" 71-72 drop spindles are readily available.

3) All 71-72 oem and drop spindles only work with HD rotors.
* All 71-72 rotors are the HD version (1-1/4" wide).
* The HD rotors will require matching HD calipers and wheel bearings.

4) 71-72 steering linkage contains 11/16" diameter tie rods.
* Inner Tie rods are LH thread.
* Outer Tie rods are RH thread.
* Inner Tie Rods are a "2-year only" tie rods. (71-72 only)
* Outer Tie Rods are a "2-year only" tie rods. (71-72 only)

5) Steering Linkage:
* All 71-72 oem linkage will work with 71-72 "year specific" oem and drop spindles.

6) A-arms have steel bushings.

7) 71-72 crossmembers have the steel brake line connect the rubber brake hose on the front side of the crossmember.
* Steel reproduction brake line sets are specific to the 71-72 design.

8) Rubber brake hoses are a "2-year only" item. (71-72)

9) 6-lug aftermarket rotors are now readily available if you decide you want to keep your 6-lug style wheels on your 60-62 truck.
* Be aware that the oem 15x6.5 steel 6-lug wheels will not clear your new disc brake conversion.
* You will need to use a set of steel wheels found on the later 73-87 4x4 trucks.

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67-70 truck with

73-87 Crossmember Installed:
1) Your trucks 73-87 donor crossmember came from the factory with disc brakes.
* Using the 73-87 crossmember allows for upgrading to 73-87 style rubber bushed a-arms.
* Most replacement parts are more affordable than the "2-year" specific 71-72 model trucks.
* Most auto parts stores keep these parts "in stock".

2) Drop spindles are readily available,... but there are two versions that must match the two rotor versions below:

3) Rotors:
* There are two different widths of rotors available on the 73-87 model trucks.
3.1) HD or Heavy Duty rotors: (1-1/4" wide version) available from 73-87
* These will require matching HD bearings and calipers.
3.2) LD or Light Duty rotors: (1" wide version) available from 81-87.
* These will require matching LD bearings and calipers.

4) Steering linkage contains 11/16" diameter tie rods.
* Inner Tie rods are LH thread.
* Outer Tie rods are RH thread.
* Inner Tie Rods are 73-87 specific
* Outer Tie Rods are 73-87 specific

5) All 73-87 oem steering linkage will work with your 73-87 spindles.

6) The 1/2 ton a-arms have rubber bushed cross shafts
* (compared to the steel bushings of the 71-72 a-arms)

7) 73-87 crossmembers have the steel brake lines, connect the rubber brake hose, through a hole originally drilled in the 73-87 frame rail.
* Using these crossmembers in the older trucks will require you to fabricate some or all of your steel brake lines.
* (67-70 brake lines connect on the rear side of the crossmember)
* (71-72 brake lines connect on the front side of the crossmember)
* Steel reproduction brake line sets are specific to the 73-87 design with their proportioning valve mounted on a crossmember in front of the engine opposed to hanging below the master cylinder.

8) 73-87 rubber brake hoses are much longer than either the 63-70 drum brake hose or the 71-72 disc brake hose.

9) 6-lug aftermarket rotors are now readily available if you decide you want to keep your 6-lug style wheels.
* To use the 6-lug rotors you must have the 73-87 HD spindles,... since all aftermarket 6-lug rotors are only available in the 1-1/4" wide version.
* Be aware that the oem 15x6.5 steel 6-lug wheels will not clear your new disc brake conversion.
* You will need to use a set of steel wheels found on the later 73-87 4x4 trucks.

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67-70 truck with

71-72 Crossmember Not Yet Installed:
1) Your truck's donor 71-72 crossmember came from the factory with disc brakes.
* You can swap out the entire 67-70 crossmember in one unit.
* Only a few holes will need to be drilled or elongated.
* The best option is to use all of the 71-72 steering components.
(centerlink, tie rods, idler arm, steering box and pitman arm)

2) 67-70 steering linkage use a different centerlink and tie rods, than the 71-72 crossmember you will be installing.

3) 67-70 tie rods are 5/8" diameter,... 71-72 tie rods are 11/16" diameter (with the opposite thread direction).
* 67-70 inner tie rods are RH thread vs. 71-72 inner tie rods (that are LH thread).
* 67-70 outer tie rods are LH thread vs 71-72 outer tie rods (that are RH thread).
* Again,... It's easiest to just use all of the 71-72 steering linkage.
* You can also use all of the 73-87 steering linkage, but you will have to change the outer tie rods to the 71-72 version to match the 71-72 spindle.

4) If you must use your 67-70 centerlink and inner tie rods:
* You will be require to use a "conversion" tie rod sleeve to connect the 67-70 5/8" diameter tie rod,... to the 71-72 11/16" diameter outer tie rod.
* Here is the problem: The 67-70 inner tie rod is RH thread. The 71-72 outer tie rod is also RH thread.
* To correct this,... you must use a 63-70 outer tie rod in the inner location.
* (The 67-70 outer tie rod is LH thread)

5) If you just want to add 71-72 spindles to your existing 67-70 a-arms,... you will need to change the 67-70 upper and lower ball joint to 71-72 upper and lower ball joints.
* The outer tie rod will have to be a 71-72 outer tie rod also. (see Step #4 above)

6) Rubber brake hoses:
* You must change to a disc brake style hose.
* Early Classic Enterprises, and other suspension vendors, make a "conversion" brake hose that will connect the disc brake caliper, to the original 67-70 brake hose steel line location.
* 71-72 hoses is another option. (but I haven't personally confirmed if the steel line connection is the correct size).
* Another option is to use 73-87 hoses, (cheaper to purchase), but they are much longer, and also may need fitting adapters.
* Aftermarket steel braided hoses and AN fittings is another option.

7) You can also just swap all the components from the a-arms out and leave your original 67-70 crossmember in place.
* This will require you to completly disassemble both the original 67-70 suspension and the 71-72 donor suspension.
* This is also a good time to clean, inspect, replace or rebuild any needed components.


Links:
*http://67-72chevytrucks.com/vboard/s...+brake+install.
* Hotchkis Suspension:
http://www.truckinweb.com/tech/suspe...dup/index.html

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67-70 truck with

73-87 Crossmember Not Yet Installed:
1) Your donor 73-87 crossmember came from the factory with disc brakes.
* This swap is almost a direct bolt in, with just a few holes to drill/elongate.

2) The preferred method is to use all of the 73-87 steering linkage:
* This includes the centerlink, inner and outer tie rods, idler arm and steering box. (A great way to gain P/S)

3) If you must use the 67-70 steering components, you will need to change the tie rods:
* The 67-70 inner and outer tie rods are a smaller diameter (5/8") vs. the 73-87 tie rods larger diameter (11/16").
* The 67-70 tie rods are also the opposite thread direction of the 73-87 tie rods.
* 67-70 inner is RH thread vs. 73-87 inner which is LH thread.
* 67-70 outer is LH thread vs. 73-87 outer which is RH thread.

3.1) So to connect the 73-87 spindle to the 67-70 steering centerlink you must use a:
* 67-70 outer tie rod (LH thread) in the inner location.
* connect that to a tie rod "conversion sleeve". (these are sold by many aftermarket suspension companies).
* use a 73-87 outer (RH thread) to connect to your 73-87 spindle.
* Again,... it's much simpler to use all of the 73-87 steering components.

4) Connecting the 73-87 rubber brake lines to the 67-70 steel lines, may require steel line fabrication, or brass "inverted flare" adapters.

5) You can also just swap all the components, from the a-arms out,... and leave your original 67-70 crossmember in place.
* This will require you to completly disassemble both the original 67-70 suspension and the 73-87 donor suspension.
* This is also a good time to clean, inspect, replace or rebuild any needed components.


Links:
*http://67-72chevytrucks.com/vboard/s...+brake+install
*http://www.67-72chevytrucks.com/vboa...d.php?t=357610

*http://www.classictrucks.com/tech/05...ing/index.html

CPP Modular Spindle Install
*http://www.classicperform.com/tech_a....05.09-web.pdf

*16" WILWOOD Install:http://www.customclassictrucks.com/t...10s/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

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60-72 truck with

"Unknown" Crossmember Swap?
* This is where it's hard to determine the correct parts needed.

Here's the break down by year:

Disc Brake Spindle:
*60-70 (Aftermarket Conversion Spindles)
*71-72 (oem or drop)
*73-87 (oem or drop)

C10
Grouped by Differences:
*60-62
*63-70
*71-72
*73-87 (HD 1.25" wide rotors)
*81-87 (LD 1.00" wide rotors)
**Some 81-87 trucks also had the HD rotors**
** All Aftermarket 6-lug "Conversion Rotors Are the HD 1.25" wide version**
C20
*71-87

Rotors:
*71-72 (1.25" wide)
*73-87 (HD 1.25" wide rotors)
*81-87 (LD 1.00" wide rotors)
**Some 81-87 trucks also had the HD rotors**
** All Aftermarket 6-lug "Conversion Rotors Are the HD 1.25" wide version**

Calipers:
*71-72 (1.25" wide)
*73-87 (HD 1.25" wide rotors)
*81-87 (LD 1.00" wide rotors)
**Some 81-87 trucks also had the HD rotors**
** All Aftermarket 6-lug "Conversion Rotors Are the HD 1.25" wide version**

Upper Ball Joint:
Grouped by Differences:
C10
*60-62
*63-70
*71-72
*73-87
C20
*71-87

Lower Ball Joint:
Grouped by Differences:
C10
*60-62
*63-70
*71-87
C20
*71-87

Control Arm Upper Cross Shafts:
Grouped by Differences:
C10
*60-62
*63-72
*73-87
C20
*63-87

Control Arm Lower Cross Shafts:
Grouped by Differences:
C10
*60-62
*63-72
*73-87
C20
*67-86


Inner Tie Rods:
Grouped by Differences:
C10
*60-62
*63-64
*65-70
*71-72
*73-87
C20
*60-64 (drivers side)
*60-64 (pass. side)
*65-70
*71-87

Outer Tie Rods:
Grouped by Differences:
C10
*60-64
*65-70
*71-72
*73-87
C20
*60-64
*65-70
*71-87

Tie Rod Adjusting Sleeves
Grouped by Differences:
C10 and C20
*60-64
*65-70 (5/8" thread)
*71-87 (11/16" thread)

Centerlink:
Grouped by Differences:
*60-62
*63-64
*65-70
*71-72
*73-87

Pitman Arm:
Grouped by differences:
C10
*60-66 Manual
*60-66 P/S
*67-72 Manual
*67-87 P/S (Specify Year When Ordering)
C20
manual:
*60-66
*67-68
*69-70
*71-87
Power Steering:
*69-70
*71-87

Idler Arm
Grouped by differences:
C10
*60-62
*63-66
*67-82
*83-87
C20
*60-66
*67-82
*83-87

Steering Box:
Manual
*60-62
*63-66
*67-82
*83-87
Power Steering
__________________
Keith

Last edited by lolife99; 01-19-2013 at 08:44 AM.
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