Disc Brake Upgrade Reference Thread

[chopttop]

Have a '70 C30, am picking up a complete running '81 C30 donor truck. Had planned on doing complete crossmember swap but it has been suggested that I just swap parts onto existing cross member, donor has low milage, late '80's 454 that will be part of the swap, plan to install drop spindles on at same time. I would imagine that most of what has been referenced concerning C10's would relate across the board to the C30. Just wondering if I should remove the complete donor crossmember, rebuild it as needed w/dropped spindles and swap out crossmembers or start w/existing crossmember in '70 and swap parts from '81 ? Thanks in advance.

[Captainfab]

I don't remember for sure on a '70 C30 if the lower control arm shafts are round or flat like the '63-'66's. If they are round there is no reason you can't swap everything from the '81 including the control arms. I would suggest going with the lower control arm shaft U-bolts from the '81. I believe they are a little bigger than the '70 pieces.

If the LCA shafts on the '70 are flat, you'll have to either keep the '70 LCA's or swap the entire crossmember

[chopttop]

Thanks, will check that out.

[LostMy65]

oops,
I figured it'd be better to just start a new thread:
http://67-72chevytrucks.com/vboard/s...92#post4308992

[blackmopar]

Hey Guys - hope its cool to post in this FAQ still - Sorry if these questions were answered - I missed if they were.


will 80-87 3/4 ton or 1 ton trucks work for the conversions? What about 73-87 c20's also? As long as theyre 2wd? im assuming they would have the 1-1/4 rotors instead of light duty, right?

Im looking to swap to my 64 c10 6 lug - and keep 6 lug - i see the parts store call out for them (thanks) in one of the thread posts

a side question - ive got drop coils in my stock arms now - could I resue them? or are the 73-87 coils different for some reason? Can you run drop coils AND spindles?

Sean

[Captainfab]

The C20's and C30's prior to '88 are going to have the 8 x 6.5" wheel bolt pattern. Those parts will certainly work if you wanted the 8 x 6.5" bolt pattern.

There are 2 ways to have 6 x 5.5 front disc brakes. one is to use the factory light duty '88-'98 C2500 parts as listed earlier in this thread. Or you can use the typical '71-'87 C10 front suspension parts and then purchase the aftermarket 6 x 5.5" rotors for those spindles.

As for the springs, I believe the '73-'87 springs are a little different, but I think the early ones will work. And yes you can run both drop spindles and drop springs at the same time......many guys do to get their desired amont of drop.

Originally Posted by blackmopar

Hey Guys - hope its cool to post in this FAQ still - Sorry if these questions were answered - I missed if they were.


will 80-87 3/4 ton or 1 ton trucks work for the conversions? What about 73-87 c20's also? As long as theyre 2wd? im assuming they would have the 1-1/4 rotors instead of light duty, right?

Im looking to swap to my 64 c10 6 lug - and keep 6 lug - i see the parts store call out for them (thanks) in one of the thread posts

a side question - ive got drop coils in my stock arms now - could I resue them? or are the 73-87 coils different for some reason? Can you run drop coils AND spindles?

Sean

[blackmopar]

thanks cap'n - could I use the c20/c30 a-arms, steering components, sway bar and brake parts with aftermarket drop spindles and rotors (5 or 6)?

theres quite a few 3/4 and 1 tons as parts trucks right now in the area here for cheap

id be sourcing drop spindles anyway even if i went with a 73-87 c10 - any diff in a-arms between c10,20,and 30s in the 73-87 yrs?

i have 6 lug wheels now, but i also have 5 lug rotors and calipers from another project so Im not sure really if i want to do 5 or 6

[Captainfab]

The C20 and C30 control arms use the steel bushings just like the '63-'72 C10's did. The main issue with using the C20 or C30 control arms, is the lower ball joints are bigger than the C10's. There's really nothing to gain by swapping your '64's control arms for the C20 or C30 arms unless you want to use the '88-'98 LD C2500 parts. This would give you 6 lug front discs

If you're having trouble locating the '73-'87 C10 control arms, I would just keep your original arms. Then just buy your drop spindles, and which ever rotors you decide on.

The steering boxes are the same whether from a C10,C20 or C30. However I don't know if the steering linkage will be the same. It is doubtful. The C20 or C30 sway bars will work on your truck. Often times you will find the larger 1- 3/16" bar.

[blackmopar]

thats what i was looking for - ill keep looking for 73-87 c10! thanks again as always capt!

[panelrodder81]

My dad just did this swap on a 64 c20 w 75 c20 parts. He wanted to keep the 8lug because he had nice wheels on the truck. He had to swap the whole xmember becaused the control arms didn't match up. Also, we found that using the 75 motor mounts pushed the engine about 2 inches forward of where it was originally. Other than that it was the easiest and most problem free part of the build.

Panelrodder

Originally Posted by blackmopar

Hey Guys - hope its cool to post in this FAQ still - Sorry if these questions were answered - I missed if they were.


will 80-87 3/4 ton or 1 ton trucks work for the conversions? What about 73-87 c20's also? As long as theyre 2wd? im assuming they would have the 1-1/4 rotors instead of light duty, right?

Im looking to swap to my 64 c10 6 lug - and keep 6 lug - i see the parts store call out for them (thanks) in one of the thread posts

a side question - ive got drop coils in my stock arms now - could I resue them? or are the 73-87 coils different for some reason? Can you run drop coils AND spindles?

Sean

Posted via Mobile Device

[blackmopar]

i grabbed the whole front clip from an 85 c10 this weekend for my 64 and will start tearing down, cleaning, painting and stuff like that - couple questions

i plan on getting the DJM 3" drop spindles, can I use the drop coils i got from CPP that Im currently running in my 64 arms?

there is a valve on the 85 that mounts ahead of the x-member - is that just a factory proportioning valve or is it the pressure differential switch? It has some electrical connector that I have no clue about - should i just replace with a basic prop valve or what? i dont have anything from my harness to connect to it

the shim stack used on the upper arms is unreal - like 8 or 9 per side - any ideas why they would need to do so many? dude says oe spindles and stock coils??

[Captainfab]

I don't see why you couldn't use your current front coils. Yes that is the factory proportioning valve. The wire on it is just for a low brake warning in case of a faliure in either the front or back system. You don't have to wire that in if you don't want. I would go ahead and use the prop valve unless it is leaking at the end or at the electrical connection.

Originally Posted by blackmopar

i grabbed the whole front clip from an 85 c10 this weekend for my 64 and will start tearing down, cleaning, painting and stuff like that - couple questions

i plan on getting the DJM 3" drop spindles, can I use the drop coils i got from CPP that Im currently running in my 64 arms?

there is a valve on the 85 that mounts ahead of the x-member - is that just a factory proportioning valve or is it the pressure differential switch? It has some electrical connector that I have no clue about - should i just replace with a basic prop valve or what? i dont have anything from my harness to connect to it

the shim stack used on the upper arms is unreal - like 8 or 9 per side - any ideas why they would need to do so many? dude says oe spindles and stock coils??

[blackmopar]

thanks for the feedback Capn as always!

this front end had an alignment problem it appears - the wheels are still on it - worn heavily to the inside - and the upper control arms have a BIG shim stack - the OP said stock everything, but the front end sat pretty low without a motor in it - so the front coils were cut - any way to verify this? Thats the onyl thing i can think of here to cause the wear

[jmlcolorado]

Originally Posted by raycow

Not dumb questions at all.

6 lug rotors are available from CPP, Performance Online, and several other vendors. This is an aftermarket part that is a direct swap for the 5 lug. If your 66 has rear coil springs you can get a kit which contains weld-on brackets for the trailing arms and panhard bar. If you want 6 lug shafts for the 76 rear, you can use stock shafts for a 71-87 4WD. Your 66 shafts are too short for the 76 rear.

Ray

HEY!!! I just saw your post and was wondering if you knew where to get the kit you mentioned for the trailing arms?
Im working with an extream drop GMC C10 and the pinion angle is going to be way wrong. I knew i was going to have to vut the mounting perches off the rear end and re weld them back to where the pinion angle is at a more useable height, buit if they make the brackets still, i wont have to worry so much about saving the origional ones!
Thanks for the input!

Heres a photo pf the project for fun

[karlbenz]

I am wanting to convert to 8 lug on my 64. what do I need to do? I have a 94 3500 (non dually)parts truck. can I use anything off of it? I plan to use the rear end and all, but I see some references here to front end parts from the newer trucks

thanks

[Captainfab]

The front suspension on the '88 and up trucks is completly different than the '63-'87 C10-30 trucks and the '88-'91 R10-30 trucks. The only possibility that I can think of is you might be able to use the '94 spindle, rotors, calipers, etc. if the upper and lower ball joints will fit the '66-87 C20 or C30 lower control arms. Is your '64 currently a C10 or a C20?

[karlbenz]

it is a c10. would the upper and lower control arms from a 73-87 c20-30 swap to my mine?

[iehotrod]

Captainfab If I decide to run drop spindles from say cpp or any after market vendor. Question is what rotor and caliper will fit those A.M. spindles? Currently I am running factory power drum brakes all around.

[Dinos63]

wow!! nice work 1964c10 and captainfab!!!

[Captainfab]

Yes they will bolt right up to your '64 suspension crossmember. I would recommend drilling out the U-bolt holes and using the larger diameter later model LCA U-bolts.

I'm just not sure if the '94 3500 lower ball joint will fit either the '73-'87 C20 or C30 lower control arm. I do know that the '88-'98 1500 and LD2500 lower ball joints will fit the '67-'87 C20 lower control arms. You'll probably have to do some parts comparisons to find out for sure.

Of course if you can find a '73-'87 C20 front suspension for the right price, there is really no need to try and make the '94 parts fit. Unless you like the challenge.....

Originally Posted by karlbenz

it is a c10. would the upper and lower control arms from a 73-87 c20-30 swap to my mine?

[Captainfab]

That is something that the spindle manufacturer should tell you. If I'm not mistaken, most spindle manufacturers design their spindles to run the '71-'87 1.250: thick truck rotors, and the D52 calipers. Of course there are exceptions, so you should find out what the spindle mfg recommends for a given spindle.

Originally Posted by iehotrod

Captainfab If I decide to run drop spindles from say cpp or any after market vendor. Question is what rotor and caliper will fit those A.M. spindles? Currently I am running factory power drum brakes all around.

[iehotrod]

Thank you Captain! One vendor did not want to say instead he stated I must use their caliper. But think he is full of .....!

[Camper Special]

Ok after debating over doing disc brake swap on my 65 C20, I jumped in and picked up a 3/4 ton 1982 crossmember assembly today. The first thing I came across on tear down is the rotors have larger than 1/2 inch studs (metric ?). I plan to replace rotors & calipers. Is there another year caliper/rotor combo that will fit these spindles and have 1/2 inch studs?

[lolife99]

Those have 9/16" lug studs.
That's the standard 73-87 lug stud size.

[Camper Special]

lolife99, Thanks for responce, I guess an oversight/glitch on my part. Hope there isn't many more on this conversion attempt.