67-72 Crossmembers - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Goose · 09-16-2005, 11:32 PM

I've got a '72 GMC - anyone know if 67-71 crossmembers are interchangeable with the '72? I couldn't find this issue discussed in previous threads, so apologize if I missed it. Is there anyway to tell which year crossmember might be under the truck? Thanks.

*72CSTC5* · 09-17-2005, 01:19 AM

They are all the same crossmembers only difference is from there on out like 6 lug versus 5 lug spindles and rotors and such.

Tx Firefighter · 09-17-2005, 02:57 PM

When they went to disc brakes in 71, they completely changed the routing of the brake lines and hoses.

If the tabs for the brake hose mounts are on the back of the crossmember, it's a 70 or ealier. If the tabs are on the front of the crossmember, it's a 71 or later.

bluec10 · 09-17-2005, 10:55 PM

I'd even go so far as to say that they are interchangable from 67-87. I put a crossmember from an '84 in my previous '68 and I only had to drill 2 holes.

a squarecan · 09-17-2005, 11:24 PM

The crossmember will fit any 1/2 truck from 63-87 you just have the drum/disc issue depending on the year. Also as mentioned they changed the way the lines are ran, but that is an easy fix.

Keith

Tx Firefighter · 09-18-2005, 06:29 AM

Actually, you can use a Suburban crossmember all the way up through 91. The Suburban kept the old body style longer than the pickups did.

**N2TRUX** · 09-21-2005, 09:34 AM

Quote:

Originally Posted by Tx Firefighter

Actually, you can use a Suburban crossmember all the way up through 91. The Suburban kept the old body style longer than the pickups did.

And 91 on the crewcabs too. Of course that's 3/4 stuff, but it is the same....

swissfacade · 11-14-2005, 10:41 AM

Does any one know what year Suburban had 6 lug front disc brakes, Or if any had front and year that would be awesome.

a squarecan · 09-18-2005, 01:27 PM

That is right TX,

I always seam to forget about the suburban.

Keith

Goose · 09-19-2005, 04:02 AM

Thanks. Guess I don't have to worry about having the wrong crossmember. Alignment woes must be coming from somewhere else.

Tx Firefighter · 11-14-2005, 11:16 AM

No such thing as a 1/2 ton with disc brakes and 6 lug. You have to go aftermarket to get them that way. All OEM disc brake 1/2 tons were 5 lug.

swissfacade · 11-14-2005, 04:48 PM

Will a crossmember from a 3/4 ton Suburban fit my 69, and didn't they come with 6 lug rotors

swissfacade · 03-22-2006, 11:43 AM

Hey TX Firefighter
You said that the Suburbans kept the same frame setup from 67-91, even if it is a 3/4 ton crossmember will it fit my 69 Suburban frame and didn't they start offering 6 lug disc brakes on the Burbs in 90 or 91.

Thanks John

Tx Firefighter · 03-23-2006, 06:42 AM

Swiss, yes, as long as it's the old body style Suburban (through 91), the crossmember will swap in, even 3/4 ton ones.

Bolt patterns remained the same. The 1/2 ton Suburbans still had normal 5 lug pattern, and 3/4 tons got the same old 8 lug pattern as the earlier years.

6 lug disc brakes were found on some new body style, late 80's, early 90's light duty 3/4 ton pickup trucks. They were new body style only though, not the old one that we need for parts.

Dennis Brooks is currently doing the research as to the feasibility of using these odd ball light duty 3/4 ton rotors on earlier truck's 1/2 ton spindles.

09-16-2005, 11:32 PM	#1
Goose Goose Join Date: Jun 2000 Location: Austin Posts: 142	67-72 Crossmembers I've got a '72 GMC - anyone know if 67-71 crossmembers are interchangeable with the '72? I couldn't find this issue discussed in previous threads, so apologize if I missed it. Is there anyway to tell which year crossmember might be under the truck? Thanks. __________________ '72 GMC short-step 350/350

09-17-2005, 02:57 PM	#3
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	When they went to disc brakes in 71, they completely changed the routing of the brake lines and hoses. If the tabs for the brake hose mounts are on the back of the crossmember, it's a 70 or ealier. If the tabs are on the front of the crossmember, it's a 71 or later. __________________ I'm on the Instagram- @Gearhead_Kevin

09-17-2005, 10:55 PM	#4
bluec10 Registered User Join Date: Apr 2002 Location: Manitoba, Canada Posts: 663	I'd even go so far as to say that they are interchangable from 67-87. I put a crossmember from an '84 in my previous '68 and I only had to drill 2 holes. __________________ Present: 2015 Tacoma. Yeah, not a GM, but I love it. 1969 GMC 32,000 - fix, drive, relax, fix... 2019 BMW R1250 GSA - Yahoooooooo 1979 Honda GL 1000 - retro touring at its best. Past: '05 Sierra 4x4 - Had 270,000 KM and running well when it was written-off by a stop sign runner. '94 F-150 from the "F word" company. I'll admit it...good truck. Sold what was left of it for $800 to a guy who came to pick it up at 11:00 PM with cash in hand. Hmm. '79 Sierra Grande (Black) organ donor - perfect rebuildable 4-bolt 350 and a good TH350. '76 Sierra Grande (Orange) - hate isn't too strong a word. Kid who bought it turned it into a hot rod. '68 C-10 R.I.P. - Dad's old truck...too far gone to resurrect. '59 C-50 - with hoist. Truck is gone, wife isn't. Nuff said.

09-18-2005, 06:29 AM	#6
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Actually, you can use a Suburban crossmember all the way up through 91. The Suburban kept the old body style longer than the pickups did. __________________ I'm on the Instagram- @Gearhead_Kevin

11-14-2005, 10:41 AM	#8
swissfacade Registered User Join Date: Jun 2004 Location: Simpsonville, South Carolina Posts: 72	I want to convert my 69 Suburban to front disc brakes Does any one know what year Suburban had 6 lug front disc brakes, Or if any had front and year that would be awesome.

09-17-2005, 01:19 AM	#2
72CSTC5 Account Suspended Join Date: Nov 2004 Location: Deer Park, Tx. Posts: 2,522	They are all the same crossmembers only difference is from there on out like 6 lug versus 5 lug spindles and rotors and such.

09-17-2005, 11:24 PM	#5
a squarecan Registered User Join Date: Mar 2004 Location: Portland, Oregon Posts: 232	The crossmember will fit any 1/2 truck from 63-87 you just have the drum/disc issue depending on the year. Also as mentioned they changed the way the lines are ran, but that is an easy fix. Keith

09-18-2005, 01:27 PM	#9
a squarecan Registered User Join Date: Mar 2004 Location: Portland, Oregon Posts: 232	That is right TX, I always seam to forget about the suburban. Keith

09-19-2005, 04:02 AM	#10
Goose Goose Join Date: Jun 2000 Location: Austin Posts: 142	Thanks. Guess I don't have to worry about having the wrong crossmember. Alignment woes must be coming from somewhere else. __________________ '72 GMC short-step 350/350

11-14-2005, 11:16 AM	#11
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Re: 67-72 Crossmembers No such thing as a 1/2 ton with disc brakes and 6 lug. You have to go aftermarket to get them that way. All OEM disc brake 1/2 tons were 5 lug. __________________ I'm on the Instagram- @Gearhead_Kevin

11-14-2005, 04:48 PM	#12
swissfacade Registered User Join Date: Jun 2004 Location: Simpsonville, South Carolina Posts: 72	What about the 3/4 ton series Will a crossmember from a 3/4 ton Suburban fit my 69, and didn't they come with 6 lug rotors

03-22-2006, 11:43 AM	#13
swissfacade Registered User Join Date: Jun 2004 Location: Simpsonville, South Carolina Posts: 72	Re: 67-72 Crossmembers Hey TX Firefighter You said that the Suburbans kept the same frame setup from 67-91, even if it is a 3/4 ton crossmember will it fit my 69 Suburban frame and didn't they start offering 6 lug disc brakes on the Burbs in 90 or 91. Thanks John

03-23-2006, 06:42 AM	#14
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Re: 67-72 Crossmembers Swiss, yes, as long as it's the old body style Suburban (through 91), the crossmember will swap in, even 3/4 ton ones. Bolt patterns remained the same. The 1/2 ton Suburbans still had normal 5 lug pattern, and 3/4 tons got the same old 8 lug pattern as the earlier years. 6 lug disc brakes were found on some new body style, late 80's, early 90's light duty 3/4 ton pickup trucks. They were new body style only though, not the old one that we need for parts. Dennis Brooks is currently doing the research as to the feasibility of using these odd ball light duty 3/4 ton rotors on earlier truck's 1/2 ton spindles. __________________ I'm on the Instagram- @Gearhead_Kevin

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