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Old 06-16-2022, 12:03 PM   #73
lolife99
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Join Date: Nov 2002
Location: Mid-MO
Posts: 22,683
Re: "Drum to Disc" conversions 67-70 pics and videos

I addressed the steering issues in this section:

QUOTE:

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.
__________________
Keith

Convert to disc brakes.
http://67-72chevytrucks.com/vboard/s...d.php?t=444823
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