The Stovebolt Site Forums The Shop Area General Truck Talk Front cross member

Good evening Stove Bolters!

Anyone ever seen the core support mount holes broken out on the front cross member of a 47-54 Chevy pickup? Both holes on my 49 1/2 ton is, and the other night I was watching a video on YouTube, and a guy was restoring a 49 Chevy pickup and one hole in his front cross member was broken out huge, way worse then mine.

I have owned a lot of these old Chevy's over the years but never had one broke out like this.

I assume it's because the core support was allowed to run lose. Just posting for discussion. I think we are going to weld in some 1/4" plate and re-drill the holes.

Kevin

Probably,
Engines are kind of heavy and like to torque out of place a lot.
Kind of like the old AMF American Machine and Foundry Harley Davidson motor scooters. Rattle traps

The entire front clip, radiator, radiator support, grill, etc are supported at that tiny spot on the crossmember. As you have mentioned, loosely. These trucks were driven hard on rough roads and in ag fields. If one has a truck without wallered out front crossmember holes, it was not likely used on a farm.

What Carl said.
That looks very similar to my front crossmember. The little sheet metal stands where the core support bolts to the crossmember had completely collapsed and were replaced by 1/2" steel plate wrapped up around the sides of the core support along with some plate welded into the inside. I think the core support weighs about 20 lbs. Mine has enough of the original oblong holes to locate them when I weld plate back in to the crossmember.

The GMC radiator support is spring mounted, is the Chevy version rigid mount ?

The Chevy is rigid. No spring, and only a square piece of rubber pad between the cross member and core support mount bracket.

Kevin

do other people see their Chevy radiators fail on either top end where the side mounting flange rips off the tank (solder lets go)
the body roll and twist gets transferred to the actual radiator too much by design
the GMC solution seems better to me, that bracket looks more ridged and doesn't transfer forces onto the radiator mounting flanges

i made sure my chevy radiator floats on it's 6 bolts by not tightening them much at all
i'm trying to limit the forces on the poor radiator now that i got it all re-soldered from the rad shop
-stan

Mine failed at the junction between the tank and the fill neck. No stress there... just time, vibration, and who knows what for coolant over the last several decades.

Over the years, Chevrolet improved the durability of the radiator support assembly to prevent torque damage to the radiator from side-to-side sway of the entire front clip.
One was the inclusion of the X bars welded in front of the radiator. Another was the long rods which go from the lower radiator baffle to the radiator support sides near the top
The change from the single center rear cab mount to the two rear shackle mounts likely aided in preventing damage to the radiator by reducing overall motion of the entire cab/front clip.
A question for you Big Truck fellows. How are the radiator support lower "feet" which the bolts go through at the bottom arranged? Are there two feet spaced far apart or do they have a single center "foot'?

Attached is the 1947-54 Factory Assembly Manual mounting instruction for the radiator support to frame crossmember.
Sec. 11 Sheet 2.11

There are also two braces/rods & brackets (Sec. 11 Sheet 12.00) that support the upper fender to the firewall.
They may play a roll in keeping body sheet metal from shifting around.

1/2 ton use two mounting bolts on radiator support to frame crossmember. (check attached)
3/4 ton and up use two bolts in center of radiator support to frame crossmember. Sec.11 Sheet 2.12

xfiles

I worked as a mechanic in a logging camp years ago (many). Radiators and supports were a constant problem as was all the front sheet metal. We would add springs under the radiator supports and under the nuts that secured them.(similar to the GMC drawing) on any newly acquired trucks that didn't have them. I remember the foreman coming by with a quart of stop leak for me to add after I'd installed a newly re-cored radiator. The radiator on my AD Chev pickup had begun leaking from the corners and he suggested that after I had it repaired that I only use three bolts to secure it: two on one side and one on the other. The radiator survived but eventually the support hoop that holds up the whole front end cracked between the two bolts that support it. I gusseted it never had a problem after that but I did add the springs like on the big trucks. I also spent a lot of time welding cracked fenders and mirror brackets.