Replace rear shock crossmember? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

crakarjax · 03-21-2016, 12:06 AM

I'm installing c-notches right now and removed the shock crossmember to make it easier to work in the area. I'm debating whether to use it (it's in great condition) or install something tubular. I'm moving the shocks so I don't care about mounting them to this crossmember, but I'm also mounting bags to the frame and the bag fittings will be run through a hole in the frame, so clearance for that is a concern.

How do tubular crossmembers compare in rigidity to the stock crossmember?
I've seen universal tubular crossmembers (trim to find and weld-on ends) -- has anyone placed these in a non-stock location and is there any benefit to doing so?
Any specific product recommendations?

crakarjax · 03-21-2016, 06:28 PM

Any thoughts? As I've researched this, I see people (including Hotchkis) adding gussets to the top of the stock shock crossmember. I'm kinda leaning toward reinstalling it now since the c-notch doesn't want to line up quite right without the added thickness below the frame, but since I have the C-20 frame stiffeners I'll need longer bolts to do the install and am still not sure how the airbag install would turn out.

**Ironangel** · 03-21-2016, 10:30 PM

If the air bag kit was designed for 67-72 frames, the stock crossmember shouldnt be in the way of anything...

crakarjax · 03-22-2016, 12:40 AM

Quote:

Originally Posted by Ironangel

If the air bag kit was designed for 67-72 frames, the stock crossmember shouldnt be in the way of anything...

It's not a kit, just some bags and 90* fittings... I'm not using upper cups like I've seen elsewhere, so the fitting will be poking through the frame and x-member support.

**Ironangel** · 03-22-2016, 01:18 AM

Quote:

Originally Posted by crakarjax

It's not a kit, just some bags and 90* fittings... I'm not using upper cups like I've seen elsewhere, so the fitting will be poking through the frame and x-member support.

I see...If your relocating your shocks then a tubular aftermarket or modified stock crossmember should be ok as long as a gusset is used to support the tube connection from the either upper or lower (depending where you locate the tube x-member) "C" portion of the frame rail. Most c-notched trucks will never see loads and frame twisting stresses that constitute full blown frame rail integrity...

Andy4639 · 03-22-2016, 05:55 AM

Quote:

Originally Posted by crakarjax

Any thoughts? As I've researched this, I see people (including Hotchkis) adding gussets to the top of the stock shock crossmember. I'm kinda leaning toward reinstalling it now since the c-notch doesn't want to line up quite right without the added thickness below the frame, but since I have the C-20 frame stiffeners I'll need longer bolts to do the install and am still not sure how the airbag install would turn out.

Look at the 'NO LIMIT" shock relocator kit. It is a nice kit and helps with rear body roll as well since they are mounted outside the frame rails. A good fab person could easly do this them selves. The link is to the kit.

http://67-72chevytrucks.com/vboard/s...d.php?t=477839

crakarjax · 03-22-2016, 11:13 AM

Quote:

Originally Posted by Andy4639

Look at the 'NO LIMIT" shock relocator kit. It is a nice kit and helps with rear body roll as well since they are mounted outside the frame rails. A good fab person could easly do this them selves. The link is to the kit.

http://67-72chevytrucks.com/vboard/s...d.php?t=477839

I am planning to relocate my shocks, I'm just going to mount them on the frame rails. I really just need to figure out what to do with the shock crossmember since I don't have shocks mounted to it anymore.

Anyone know the stiffness of the stock x-member vs a tubular replacement by chance?

Andy4639 · 03-22-2016, 01:58 PM

Just leave it off. all it is is a mounting bracket for the shocks it doesn't add anything to the frame.

crakarjax · 03-22-2016, 04:03 PM

Quote:

Originally Posted by Andy4639

Just leave it off. all it is is a mounting bracket for the shocks it doesn't add anything to the frame.

Well I'm sure it adds some stiffness, and I've seen others use it to tie in cross bracing -- I'll attach some pics if I can find them.

attached

Now, I'm thinking maybe I can chuck that crossmember and use a welder series sway bar as pictured, but going through the frame while adding some boxing in the area as well. Then I can also tie in some diagonal tubing between the sway bar outer tube and the frame, similar to the pictured cross-bracing.

You can see more details in the guy's build thread here
http://67-72chevytrucks.com/vboard/s...d.php?t=534956

But his panhard bar placement is suspect so I'm not sure if the placement of his bracing is optimal.

03-21-2016, 12:06 AM	#1
crakarjax Registered User Join Date: Dec 2009 Location: Kirkland, WA Posts: 1,302	Replace rear shock crossmember? I'm installing c-notches right now and removed the shock crossmember to make it easier to work in the area. I'm debating whether to use it (it's in great condition) or install something tubular. I'm moving the shocks so I don't care about mounting them to this crossmember, but I'm also mounting bags to the frame and the bag fittings will be run through a hole in the frame, so clearance for that is a concern. How do tubular crossmembers compare in rigidity to the stock crossmember? I've seen universal tubular crossmembers (trim to find and weld-on ends) -- has anyone placed these in a non-stock location and is there any benefit to doing so? Any specific product recommendations? Attached Images __________________ 1968 LWB C20 / AC / Wood Bed

03-21-2016, 06:28 PM	#2
crakarjax Registered User Join Date: Dec 2009 Location: Kirkland, WA Posts: 1,302	Re: Replace rear shock crossmember? Any thoughts? As I've researched this, I see people (including Hotchkis) adding gussets to the top of the stock shock crossmember. I'm kinda leaning toward reinstalling it now since the c-notch doesn't want to line up quite right without the added thickness below the frame, but since I have the C-20 frame stiffeners I'll need longer bolts to do the install and am still not sure how the airbag install would turn out. __________________ 1968 LWB C20 / AC / Wood Bed

03-21-2016, 10:30 PM	#3
Ironangel Senior Member Join Date: Feb 2010 Location: Falls City, Nebraska "100 Miles From Nowhere" Posts: 2,219	Re: Replace rear shock crossmember? If the air bag kit was designed for 67-72 frames, the stock crossmember shouldnt be in the way of anything... __________________ Michael of the clan Hill, "Two Seventy Two's" 71 1-ton Dually 350 4-Speed 71 C/50 Grain Truck, 350 Split-Axle 4-Speed 02 3/4 ton Express 14 Indian Chief Vintage 1952 Ford 8N, "Only Ford Allowed On The Property" "Be American, Buy American"

03-22-2016, 01:58 PM	#8
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,945	Re: Replace rear shock crossmember? Just leave it off. all it is is a mounting bracket for the shocks it doesn't add anything to the frame. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.