Just need some reminders on spindle swap 68 to 72

[Legend56BC]

Hello All,Ok most of you know me as a street stock driver with a street stock truck but I did do alot of trucks(street rodding) in my time mainly kept stock except for my 56 Chevy Panel.So here is my problem,I have a 68 GMC pickup 1/2T fleetside(Canadian model)same as Chevy and I have set of 72 Chevy 1/2T spindles and rotors as spares for my race truck but really don't need them.I have the 68 on the 2 poster ready to go and am wondering about type of flex brake hose I use going to the disk brake calipers, and the PB unit I have is off a 69 Chevy drum brake setup so do I change the master cylinder or just the brake booster pin from drum to PB?I also think I have to replace the poporotioning valve to the disc brake one? Is there any else I'm missing before I really dig into this swap? Yes I am getting the rotors turned new calipers etc but other than that anything I'm missing?This going back and forth from racing to rodding is stretching my brain cells to the max! Paul #72

[Bus Ted Knuckle]

I did the same swap, it worked great, but I had a 72 in the back yard to take the lines, hoses, proportioning valve from. If you have a good parts truck it is the way to go, if not you may want to think about a conversion kit. Here is the breakdown.

You will need:

1. 72 model upper and lower ball joints

2. the whole 72 tie-rod, outer end all the way to the other outer end, you will need the pitman arm and the idler arm too. Some people say that you can just swap the 72 outer tie rod ends onto your 68 inners, but you can't do that (threads are different).

3. 72 master cylinder, with proportioning valve

4. 72 front brake lines and rubber hoses

5. 72 rear brake hose if swapping in a 72 rear as well.

You will need the brackets to hold the brake line ends where they attach to the hoses at the front wheels...I cut mine off of the back of the cross-member and tacked them on the front, where they need to be for disc brakes.

You will need to change the front steel lines to 72 stuff. The front brake lines for drum brakes have different fittings, and exit on the wrong side fo the cross member, so they will not work with the newer brake hoses. The steel line to the rear brakes is the same, but the rear rubber hose is a different length.

The last major thing is trimming the steering stops on the 72 spindles, not hard, just take about an inch off of each side with a sawzall.

You will probably need to take away some camber, and add some caster to correct alignment.

It is a good swap and I recommend it, especially if you do not already have to pull the engine.

[Legend56BC]

Thanks Bill for the quick reply,I have new 68 tierod ends,idler arm
on the 68 now so if I have to replace them the only 72 ones I have are used and I don't know how good so I think I will just replace the shoes until the fall when I take it off the road.I will keep this on my office board until then.I have 4 15X7" 5 on 5 Aero Chrome stock car wheels but need street tires and I was going to pull the rear axles and them redrilled to 5 on 5 as well and use the 5/8 course racing studs as well.So instead of just using the spindles I should use the upper and lower control arms that are still on the 72 spindles to have the 72 upper and lower ball joints as well?
Thanks Paul

[Bus Ted Knuckle]

Originally Posted by Legend56BC

Thanks Bill for the quick reply,I have new 68 tierod ends,idler arm
on the 68 now so if I have to replace them the only 72 ones I have are used and I don't know how good so I think I will just replace the shoes until the fall when I take it off the road.I will keep this on my office board until then.I have 4 15X7" 5 on 5 Aero Chrome stock car wheels but need street tires and I was going to pull the rear axles and them redrilled to 5 on 5 as well and use the 5/8 course racing studs as well.So instead of just using the spindles I should use the upper and lower control arms that are still on the 72 spindles to have the 72 upper and lower ball joints as well?
Thanks Paul

Paul, glad I could help. you can use the control arms from the 72 as well, that will keep you from having to trim the steering stops.

good luck with your project!

[breeh]

Bus Ted Knuckle, great write up!

It reminds me why I just swap out the whole front crossmember.

[Jim_PA]

Originally Posted by breeh

Bus Ted Knuckle, great write up!

It reminds me why I just swap out the whole front crossmember.

And reminds me why I SHOULD have just swapped out the whole front crossmember, or better yet, went to a 73-87 front end.

[Bus Ted Knuckle]

Originally Posted by breeh

Bus Ted Knuckle, great write up!

It reminds me why I just swap out the whole front crossmember.

breeh, You have the right idea, on my next project I'll swap a 73-87 crossmember too. The idea on this one was convenience and $$$. I needed the truck on the road quick, and I had the parts.