Clarification on Front Drum to Disc Conversion

[Talisman]

I am looking to clarify what parts are needed for a 1964 C20 3/4 ton 8-lug front disc conversion. This is the first time I will be attempting such a conversion so wanted to make sure I understood it completely.

According to FAQ I read http://http://67-72chevytrucks.com/v....php?p=4450757 if I were to keep the original cross member and A-Arms then all I would need is a spindle (71-72 or 73-87) with the corresponding matching year for the upper and lower ball joints and outer tie rods. Now of course I would expect I would also need the corresponding year for the caliper, pads, wheel bearings, etc. but is it really that simple? Are there any modifications needed?

For example, if I select a 73 - 87 spindle then my list of parts would be:
73 - 87 8-lug rotor
73 - 87 calipers, pads
73 - 87 upper and lower ball joints
73 - 87 outer tie rods
73 - 87 wheel bearings

I know this would not be a complete list of parts but just making sure it is as simple as I am reading in the FAQ. If anyone has more information and happens to have a complete list of parts for this type of conversion could you post it please?

Thanks in advance.

[Captainfab]

Yes is it that simple. The one thing with the '63-'66 C20's is that, according to another member that had done so, the hole in the lower control arm for the ball joint needs to be opened up ever so slightly to accept the disc brake lower ball joint. A comparison of the original ball joint with the disc brake ball joint with a calipers will tell you how much. I do not know the exact figures as I have never used the original control arms with a C20 disc brake conversion. I have typically changed the entire suspension, crossmember and all.

One thing that I will add is that assuming you will also be converting to power steering also, I would use the entire steering linkage from the donor truck. You will have to drill 2 new holes for the idler arm once you determine the location. This way there is no confusion later on when replacement parts are needed, and you don't need those special tierod adapter sleeves.

[Talisman]

Thanks Captainfab!

Really appreciate the response and looking forward to kicking this project off in the next week or two depending on my schedule. Once I start I will update this post with anything I learn such as the difference between the ball joint size as outlined by you.

As for power steering, this was done some time ago so I am hoping to use everything as it is (even if I have to use the special adapter sleeve for the tie rods) but that will be a decision perhaps at game time or I will go with your suggestion....thanks for the tip!

By the way, when we talk about the special adapter tie rod sleeve, are we talking about when you use the original outter tie rod as the inner and purchase the correct year (same year as spindle) for the outter tie rod? If so, is there a place that sells them?

One other note, I would also like to install a hydro boost braking system (braking is manual at this time) but just like the conversion....it will be my first time. So if you have any knowledge or tips on the subject or can point me in the right direction to learn how to accomplish it...I am all ears or is that eyes in this instance.

[Captainfab]

Yes the aluminum adapter sleeve I spoke of can be found at CPP and I believe POL. Yes it is to adapt the original outer used as an inner and the new disc brake spindle outer.

I make a hydroboost mounting plate that is used on conjunction with my booster brackets to mount most any GM hydroboost unit to your firewall without drilling any more holes. My booster bracket also ensures that the brake booster and master cylinder is securely bolted to the brake pedal bracket under the dash as it is designed to be. Then it is as simple as plumbing the hydroboost in series with your power steering box. It is advisable to run a hydroboost specific pump which has 2 return ports.

Originally Posted by Talisman

Thanks Captainfab!

Really appreciate the response and looking forward to kicking this project off in the next week or two depending on my schedule. Once I start I will update this post with anything I learn such as the difference between the ball joint size as outlined by you.

As for power steering, this was done some time ago so I am hoping to use everything as it is (even if I have to use the special adapter sleeve for the tie rods) but that will be a decision perhaps at game time or I will go with your suggestion....thanks for the tip!

By the way, when we talk about the special adapter tie rod sleeve, are we talking about when you use the original outter tie rod as the inner and purchase the correct year (same year as spindle) for the outter tie rod? If so, is there a place that sells them?

One other note, I would also like to install a hydro boost braking system (braking is manual at this time) but just like the conversion....it will be my first time. So if you have any knowledge or tips on the subject or can point me in the right direction to learn how to accomplish it...I am all ears or is that eyes in this instance.

[Talisman]

Thanks again for the reply Captianfab.

I will most likely take you up on your brackets once I decide on a unit. Can you or anyone out there suggest on a good Hydro-Boost / MC combination for my 64? I will be using drums in the rear (13 inch) and of course discs in the front.
I am seeing remanufactured Hydro's (less MC) for about $120.00 dollars (Cardone 52-9346 for Chevy and GM Trucks) to units that sell for 400 - 600 dollars. Of course there is the option of getting one from the salvage yard and rebuilding or having it rebuilt. Comments anyone?

Thanks in advance for your help!

[Captainfab]

IMO the rebuilt hydroboost unit for $120 will work just fine. Many have used one from a wrecking yard that passed a visual inspection.