Disc Brake Upgrade Reference Thread

[LostMy65]

Originally Posted by c10hevy

....clip.....how do you connect the large diameter soft brake lines from the '91 and connect them to the 1/4 " '66 hard lines. Can I get a union from home depot or someplace similar?

-Mike
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The outer diameter of the hose connection appears larger, but that's for connecting to the frame.
It's also threaded on the inside.
That's where you connect your hard brake line.


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[c10hevy]

I totally overlooked the inside, they seem a little hard to get the flared tube past the treads, but I'll investigate further tomorrow. Thanks, I was thinking I'd have to buy custom brake lines.

Much appreciated!
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[porter90]

i have a question that i havent seen yet. i have a 64 gmc and i found a 67-72 chev at a junk yard with 5 lugs and discs should the spindles bolt right up or would i need to change control arms out. any help would be awesome

[old_1966_GMC]

Wats up been a while but heres my problem changed my front end on my 65 gmc to a 73 c10 five lugs im tryin to figure out if i can use standard grade 8 bolts on the upper control arm where the shims rest on beside puttin those standard stud bolts Back in
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[Captainfab]

Yes the '71-'72 spindles will bolt up to your original control arms,as long as you install the '71-'72 ball joints. If you want to get the '71-'72 control arms along with the spindles, they will bolt up to your '64 GMC crossmember

Originally Posted by porter90

i have a question that i havent seen yet. i have a 64 gmc and i found a 67-72 chev at a junk yard with 5 lugs and discs should the spindles bolt right up or would i need to change control arms out. any help would be awesome

[Captainfab]

If you don't use the original style studs, you would have to stitch weld the grade 8 bolts, so they don't spin. If it were mine, I would check into getting replacement OEM style studs.

Originally Posted by old_1966_GMC

Wats up been a while but heres my problem changed my front end on my 65 gmc to a 73 c10 five lugs im tryin to figure out if i can use standard grade 8 bolts on the upper control arm where the shims rest on beside puttin those standard stud bolts Back in
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[porter90]

awesome! i think thats what ill do, shouldnt be too much. thanks captainfab.
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[terrylgreenjr]

My question isn't as involved as the others. I have a 77 2wd Blazer not sure which rotors I have. If I find that i have the 1" what will it take to upgrade to the 1.25" I assume its a little upgrade. Where do you measure to see which ones you have.

Thanks

[Rich 5150 69]

All depends on the calipers, are you using the calipers from the same donor vehicle..?

[terrylgreenjr]

I'm not sure whats on my blazer, but if I want 1.25" rotors Will I need 1.25" calipers also? I there anything else besides rotors and calipers that are different?

[Captainfab]

The spindle is also different for the 1.25" rotors versus the 1" thick rotors.

[65Custom]

I have read through this whole thread and for what ever reason some where on this site in the past ( not this thread ) I thought that I had read that doing a cross member swap moved the front wheels forward about an inch or so when using a later cross member

now based on what I have read here that may not be the case but can someone clarify?

[Captainfab]

I'm not aware of any wheelbase changes resulting from the crossmember swap. But then again, I have not checked either. Just the change to discs, does increase the track width a bit though.

Originally Posted by 65Custom

I have read through this whole thread and for what ever reason some where on this site in the past ( not this thread ) I thought that I had read that doing a cross member swap moved the front wheels forward about an inch or so when using a later cross member

now based on what I have read here that may not be the case but can someone clarify?

[65Custom]

Originally Posted by Captainfab

I'm not aware of any wheelbase changes resulting from the crossmember swap. But then again, I have not checked either. Just the change to discs, does increase the track width a bit though.

Thanks for info, it makes sense

[55dude]

great thread and very complete! let me ask about the rearend does anyone have any pic's of the 73-87 rearend into the 65' C10? thanks!

[65ChevyC20]

What a wealth of information, thanks for putting it all together in one place to read through.
I have a scenario I would like some input on.

As you can see from my screen name I have on of these. I want to to the front disk upgrade and have read through all the posts, WOW.

Driving by a wrecking yard today I noticed a 79 C20 being loaded onto the back of a flatbed. I flipped a u turn and inquired about the truck. The truck was stripped except for the front crossmember and all the suspension and brakes, a complete front end. I asked the guy if I could buy it and he said 50 bucks. I jumped on it as my time and effort of tracking down all the parts or pulling them off a truck in a pick and pull yard is not what I consider a good time.

He brought out a cutting torch and just cut off the frame rails of the 79 C20 and loaded it in my truck. He cut the hard lines to the brakes but I am sure I will have to create my own there.

My question is should I do the complete crossmember swap or should I swap the various pieces over to the crossmember on my 65. Which would be easier is what I am asking.

Thanks for all the info that this site provides!

[Captainfab]

Well from a easier perspective, just switching the ball joints, spindles, rotors, calipers, etc. would be the easiest. The '79 lower control arms will not bolt up to your '65's crossmember, since there are no saddles there.. If your '65 has the engine in it, switching the crossmember can be done, but it is a bit more of a challenge. If the engine is out, it's a piece of cake. Did you get the steering box with the front suspension?

[65ChevyC20]

Originally Posted by Captainfab

. Did you get the steering box with the front suspension?

I did get the steering gear box along with all the other componentry. I want to upgrade to power steering also.

The motor is still in my 65. I may just swap the pieces over then and leave the engine in the vehicle.

One other question, since the front crossmember is out of the vehicle I can no longer use the jack stand and floor jack to release pressure one the coil spring. I don't want it to explode in my face, any suggestions besides wrapping a tie down strap around the upper and lower arms?

[Captainfab]

I've not had an issue with disassembiling a front suspension out from the truck. I just stand to the side when I hit the lower boss on the spindle to release the lower ball joint. If you're worried about it, tie a rope or a ratchet strap to the spring and to somewhere else on the suspension, to keep it in place.

[restorevival]

Full X-member vs component swap and power steering upgrade…?

First of all, thank you to everyone for the wealth of info. This is my first post, though I have been reading this forum for quite some time. I think I have this all figured out, but there are a couple points that I would like some confirmation/correction on. Can someone please review and tell me what I am missing…

My truck: ’66 GMC 1000, 305 V6

This is my daily driver, so ultimately I’m looking for the least amount of down time for the truck. A weekend would be stellar. In the end I want to have front power disc brakes and power steering, though the brake upgrade takes priority over the steering upgrade.

From reading this thread, I have gathered that a full cross member swap would be least amount of future maintenance the least amount of down time if I rebuild all necessary parts on the donor suspension (don’t have a donor yet) and bolt on some aftermarket 6 lug rotors prior to putting my truck on jack stands. What can I expect to run into with the engine in the truck? I'll likely need to drill/"stretch" some holes, what else? According to post #197 I may not even need to drill any holes… But according to posts #216-217 this is not the easiest way of swapping…

If I upgrade steering at the same time, surely there are other things to do. I have not searched the forum for steering upgrade threads yet. I have read CPP’s page on how to do it, but their instructions are based on my ’66 suspension. What do I need to grab from the donor vehicle to make the steering upgrade as complete and painless as possible? (suggested links?)

I’ve never taken on a project quite this large (on my own) but have plenty of experience otherwise. Just don’t want to get myself half way through and start kicking things in frustration…

Also, my truck has aftermarket wheels. If there is going to be a caliper clearance issue with my wheels, where would it be? What part of the wheel should I measure to see if they will work?

Necessary adapters...?:
brake booster adapter plate, power steering box adapter plate, possible brake line fitting adapters, what else?

Donor requirements…?:
1.25” rotors
’73-’87 pickup; ’73-’91 suburban

And finally: can I use a 1987 G20 Conversion Van as a donor?

Thank you in advance!

Here's the truck as it currently stands, all stock... except for the bed of course.

[Captainfab]

Since your truck is a 1/2 ton and you don't plan on removing the engine, I would just swap the control arms, and everything outward from there. As always I do recommend upgrading to the larger diameter lower control arm shaft U-bolts. This will require drilling out the holes in the crossmember.

As for the steering, you will of course need the steering box with the pitman arm. And I recommend using the newer steering linkage, complete from spindle to spindle. This will require drilling holes for the newer style idler arm. I just take measurements from the donor truck, to locate the idler arm on the early frame and drill the holes. You will also need a steering box adapter plate. I sell those along with the tube and flange, which makes the installation a little easier, You can also use the lower steering column shaft from the donor if you like. And don't forget you will need a power steeering pump, mounting brackets, pulleys and hoses. The pulleys and brackets will need to be specific to the engine you are using. In your case, the GMC V6, which can be hard to find. You might consider fabbing some, or having someone do it for you if you don't have the means.

If upgrading to power brakes also, you can use the booster and master from the donor if you like. I also sell booster brackets, that work with a few specific boosters that are commonly available. These are a direct bolt onto your firewall.

I don't know for certain on the '87 G20 parts, but I do know that a '85 G20 would work. I would think the '87 would be the same, but I would verify before purchasing. Maybe do a part interchange at an auto parts store, to see. If you are planning on the aftermarket 6 lug conversion rotors, then you will need the spindles for the 1.250 thick rotors.

[restorevival]

Thanks Captainfab!

I cross referenced as many parts as I could think of from '87 G20 to '85 G20 (from Oreilly auto parts) and the only thing that I could find different is the Control Arm Shaft Kit. However, when crossing the entire Control Arm Assembly which includes the shaft, the parts numbers are the same. Any thoughts as to the difference there?

Otherwise, it looks as though I may have found a good donor. If so I will be contacting you for those adapter plates.

Thanks again for the help.

[restorevival]

To be more exact, only the front upper control arm shaft kit parts numbers are different. The lower shaft parts numbers are the same. Also cross referenced to '85 C10 with the same results. '85 c10 upper shaft = '85 G20 upper shaft but not equal to '87 G20 upper shaft...

[Captainfab]

Hmmmm, I wonder what the difference is with the '87 G20 upper shaft? If you can get the van cheap enough, you might try it and see if the upper control arms will work on your truck.

Also I don't believe I mentioned that the G series van front suspension crossmembers are not interchangeable with the pickups.

[restorevival]

Thanks again for the info Captainfab. Parts compatibility from the G20 is currently a moot point as the guy that has it for sale is keeping the front end to do exactly the same conversion on his '63 C10.

Visual inspection of the shafts on NAPA's website shows no difference, but I did not get a chance to check them in person.

Back to hunting for a donor for now... will contact you for adapter plates when I find one.

Thanks