easy disc brake swap - Page 3 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

FirstGen · 04-06-2005, 01:14 AM

Basically these are the parts I used:

1968 C20 lower control arms
1990 3/4 ton Light Duty 2X4 must have (1.25" rotors) spindles
1990 1.25" thick 6 lug rotors
1990 calipers off same truck
1990 upper and lower ball joints
1990 outer tie rods
inner tie rods MOOG part #ES2020RL
1990 style tie rod coupler

The only catch is to cut 3/4" off each end of both tie rods on each side of the truck so you can have enough room to align the truck. Well at least I had to since mine is lowered 4" in the front.

The front end I bought off the 1990 truck was 5 lug. All I did was went and bought the 6 lug rotors and bolted them on. If you wanted to stay with the 5 lug, you'd save yourself about $120 bucks.

After everything is done, you will now have 14mm studs on the front. I fixed this by drilling my rear axles and pressing in 14mm studs in the rear also but you wouldn't have to do this... I plan on going to a rear disc setup using a floating rotor design and so this helps that plan also...

Good luck.

sixty8c10 · 04-06-2005, 12:12 PM

what ball joints did you use?

FirstGen · 04-06-2005, 05:21 PM

Quote:

Originally Posted by sixty8c10

what ball joints did you use?

if you read my last reply it's says 1990 upper and lower ball joints.

shifty · 04-06-2005, 06:32 PM

Thanks for the info, FirstGen. Did you need to modify your brake line or brake line assembly at all? I've noticed some people (normally in the back) welding on new L-brackets to hold the tap between the hard line and the flex line. Did you re-use all existing fittings and lines or buy new ones?

FirstGen · 04-06-2005, 08:32 PM

I used the rubber lines off the 1990 truck and used the factory mount from the 1990 to secure the line to the frame. Never ran new steel lines until later when I just wanted to, it wasn't nessary to do the swap.

JRB · 11-21-2005, 07:16 PM

DO you know if the 68 3/4 ton Lower A-Arm is the same as the 69? Thanks in advance for the help.

Bruce

FirstGen · 11-21-2005, 08:22 PM

Quote:

Originally Posted by JRB

DO you know if the 68 3/4 ton Lower A-Arm is the same as the 69? Thanks in advance for the help.

Bruce

I'm sure it is. Call Ed at Mothertruckers and ask him, he will know for sure...

krue · 11-22-2005, 07:21 PM

Quote:

Originally Posted by JRB

DO you know if the 68 3/4 ton Lower A-Arm is the same as the 69? Thanks in advance for the help.

Bruce

Ask on the main board for confirmation, but I'm pretty sure they are the same as well.

doc70sub · 11-26-2005, 08:28 PM

I wonder if you can utilize the '88-'98 3" lift spindle while doing this swap....I'd like a little lift on my '70 C-10 Sub!!

GMC69mnypit · 12-02-2005, 07:35 PM

Did anybody else that did this swap with factory ride height have serious alignment issues like I have??? Not toe, caster / camber...

68jimmy · 02-06-2006, 04:23 PM

Quote:

Originally Posted by GMC69mnypit

Did anybody else that did this swap with factory ride height have serious alignment issues like I have??? Not toe, caster / camber...

GMC69mnypit, did you ever get that alignment issue resolved? If so what was the cure?

thanks.

jamon8 · 04-24-2006, 08:58 AM

I got one question!

Why do you have to have the 70 3/4 ton lower control arms to make the 87 and up spindals work.

I have a 69 c10 and a 89 1500 parts truck that I am taking the trans out of.

This sounds like the way to go and I am glad I got involved in this forum.

Do I HAVE TO GET the 3/4 lower control arms?

doc70sub · 04-24-2006, 10:27 PM

Yup, for the larger ball joint in the 3/4-ton a-arm to match the larger later model lower ball joint.

jamon8 · 04-25-2006, 07:41 AM

can you put a 3/4 ton ball joint in a 1/2 ton lower control arm.

I am really enjoying these modifications. It seems that the sky is the limit with these old trucks

HarrisonTX · 04-28-2006, 05:35 AM

Hello
What a great post
I have a '69 3/4 custom camper, would i just need to get parts from a newer 3/4ton? Thanks!

texascowboy593 · 05-17-2006, 04:47 PM

to keep this alive and kickin'...Anyone know if it'll work on a 67 GMC??? Thx so much in advance!

04-06-2005, 01:14 AM	#51
FirstGen Just Don't Stop! Join Date: Feb 2004 Location: Dallas Posts: 1,239	Basically these are the parts I used: 1968 C20 lower control arms 1990 3/4 ton Light Duty 2X4 must have (1.25" rotors) spindles 1990 1.25" thick 6 lug rotors 1990 calipers off same truck 1990 upper and lower ball joints 1990 outer tie rods inner tie rods MOOG part #ES2020RL 1990 style tie rod coupler The only catch is to cut 3/4" off each end of both tie rods on each side of the truck so you can have enough room to align the truck. Well at least I had to since mine is lowered 4" in the front. The front end I bought off the 1990 truck was 5 lug. All I did was went and bought the 6 lug rotors and bolted them on. If you wanted to stay with the 5 lug, you'd save yourself about $120 bucks. After everything is done, you will now have 14mm studs on the front. I fixed this by drilling my rear axles and pressing in 14mm studs in the rear also but you wouldn't have to do this... I plan on going to a rear disc setup using a floating rotor design and so this helps that plan also... Good luck. __________________ 1968 C10 build in process TT LSA/6L90e/9"

04-06-2005, 12:12 PM	#52
sixty8c10 MY EX DRIVES A BROOM Join Date: Nov 2003 Location: Herington, KS Posts: 869	what ball joints did you use? __________________ They say nobody's perfect. I'm a nobody, so I must be perfect. Building Nemo -1968 C10 Long Bed FRED -1947 KB-2 International

04-06-2005, 06:32 PM	#54
shifty Questionable Join Date: Mar 2005 Location: Atlanta Posts: 13,373	Thanks for the info, FirstGen. Did you need to modify your brake line or brake line assembly at all? I've noticed some people (normally in the back) welding on new L-brackets to hold the tap between the hard line and the flex line. Did you re-use all existing fittings and lines or buy new ones? __________________ If I've got anything up for grabs, it'll be here: 7-hole gauge cluster for a 67-72 p/u FREE (link) I can't check the forum daily. If I don't reply to you within 24 hours, drop me a PM! I'm (hopefully) still alive and will reply faster to a PM.

04-06-2005, 08:32 PM	#55
FirstGen Just Don't Stop! Join Date: Feb 2004 Location: Dallas Posts: 1,239	I used the rubber lines off the 1990 truck and used the factory mount from the 1990 to secure the line to the frame. Never ran new steel lines until later when I just wanted to, it wasn't nessary to do the swap. __________________ 1968 C10 build in process TT LSA/6L90e/9"

11-21-2005, 07:16 PM	#56
JRB Senior Member Join Date: Nov 2005 Location: Portland Oregon Posts: 287	Re: easy disc brake swap DO you know if the 68 3/4 ton Lower A-Arm is the same as the 69? Thanks in advance for the help. Bruce

11-26-2005, 08:28 PM	#59
doc70sub Registered User Join Date: Dec 2000 Location: Thomasville, NC Posts: 669	Re: easy disc brake swap I wonder if you can utilize the '88-'98 3" lift spindle while doing this swap....I'd like a little lift on my '70 C-10 Sub!! __________________ 1970 Sub C-10 - 350/TH-350/3.73 12-bolt Came home from the hospital in it & mine ever since. 1966 Catalina Ventura 2-door fastback 389/TH400

12-02-2005, 07:35 PM	#60
GMC69mnypit !Women...!!!! Join Date: Jan 2005 Location: South of Hays, Kansas Posts: 40	Re: easy disc brake swap Did anybody else that did this swap with factory ride height have serious alignment issues like I have??? Not toe, caster / camber... __________________ '69 GMC 1/2T LWB 2WD '02 Silverado 2500HD 4X4 '79 ElCamino SS

04-24-2006, 08:58 AM	#62
jamon8 Registered User Join Date: Apr 2006 Location: southern Il Posts: 335	Re: easy disc brake swap I got one question! Why do you have to have the 70 3/4 ton lower control arms to make the 87 and up spindals work. I have a 69 c10 and a 89 1500 parts truck that I am taking the trans out of. This sounds like the way to go and I am glad I got involved in this forum. Do I HAVE TO GET the 3/4 lower control arms?

04-24-2006, 10:27 PM	#63
doc70sub Registered User Join Date: Dec 2000 Location: Thomasville, NC Posts: 669	Re: easy disc brake swap Yup, for the larger ball joint in the 3/4-ton a-arm to match the larger later model lower ball joint. __________________ 1970 Sub C-10 - 350/TH-350/3.73 12-bolt Came home from the hospital in it & mine ever since. 1966 Catalina Ventura 2-door fastback 389/TH400

04-25-2006, 07:41 AM	#64
jamon8 Registered User Join Date: Apr 2006 Location: southern Il Posts: 335	Re: easy disc brake swap can you put a 3/4 ton ball joint in a 1/2 ton lower control arm. I am really enjoying these modifications. It seems that the sky is the limit with these old trucks

04-28-2006, 05:35 AM	#65
HarrisonTX Registered User Join Date: Nov 2003 Location: Waco TX Posts: 247	Re: easy disc brake swap Hello What a great post I have a '69 3/4 custom camper, would i just need to get parts from a newer 3/4ton? Thanks! __________________ '69 custom/camper '74 260z 302 chevy/tko500 swap in progrss '79 Malibu 355 all forged 4 speed car. '86 k5 blazer '06 Duramax

05-17-2006, 04:47 PM	#66
texascowboy593 Registered User Join Date: Dec 2004 Location: Southeast Tx Posts: 1,302	Re: easy disc brake swap to keep this alive and kickin'...Anyone know if it'll work on a 67 GMC??? Thx so much in advance! __________________ "The rays of light thru the Shiner Bock bottle make me wanna turn the key and put down the throttle...and get lost down 35" - Jason Boland www.YouTube.com/user/593Films - Watch My Videos! 1977 Silverado K10 2014 Dodge Durango (Wife-mobile) 2008 Dodge Ram Lone Star Edition (Daily driver)

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