Rusted rear bumpers...

Paul Steinberg

PCS Life Member President
Staff member
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It seems that one of the items most sought after is the rear bumper for the 1965 - 1976 commercial chassis cars. This past weekend, I was given a rusted out rear bumper by Bill Marcy. After examining it, I now know why the rear bumpers rust out. At the bottom of the bumper is a 1" piece of steel that is formed at the bottom of the bumper face that is parallel to the ground, and then it makes a 90 degree bend upward to create a U shaped lip at the bumper bottom. This lip collects dirt till it is filled, and when it gets wet, the mud holds dampness in this channel. If you clean out the channel on a regular basis, your bumper will last forever. If not, then you are in risk of loosing your bumper on the road. I found that when the bumpers were made, that they used a 1/2" of weld at the top and the bottom to attach the rear bumper bracket. This is all that holds the bumper to the brackets that hold the bumper to the frame. When I picked up the bumper by the mounting brackets, one of them came off in my hand. This lead me to realize how weak the attaching method really is. If both lower sides of the bumper were badly rusted, then the only thing holding the bumper to the car is the two top welds, which are not very substantial. I can see how a rusted bumper could fall of the car while driving it, and the driver not realizing it till he got out of the car and walked to the rear.
I hope to send this bumper out for repair and re plating. I am waiting for a repair quote, which I hope will be reasonable.
 

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If people will send me pictures of their rear bumpers for all all manufacturers of commercial chassis Cadillac vehicles, I will catalog the pictures and then make a comprehensive post of all the various configurations that were used from 1965 to 1976. From what I have been told, they are all the same basic configuration, but changes were made to accommodate various stop and tail lights. Please PM me for an email address where to send pictures. Close ups preferred, along with a complete description. Rust isn't an issue for these pictures.
 
they are all the same up to the 73 then 4,5&6 are alike . the difference being the taillights . the rectangle back it light is the same in all up to the 73. the only difference is the spacer that was used on the ends to put on the factory bumper ends. the ambulances are shorter and do not have the finished end for the license plate on most of them some ambulances used the hearse license plate with a step bolted on under neath. but most have some form of a plated step bolted to the center of the bumper. Paul is right on as to why they rust out just under the mount. the mount is really cheaply welded to the bumper also. but it is held on more by the bolts the hold the bumper ends to the body. they are clear up high on the ends. a hole drilled in the bottom would have solved most of these problems with rust. as would sticking the hose behind the bumper when you wash it. each of the companies used different ways of putting the bumper on the car on the upper end. the center was of course bolted to the CC in the same way. I'll send you what I have here for your project. after you get this done maybe we can do fender skirts to.
 
Bumpers

I scanned a few pics from a 68 Superior manual and a 74 manual. I thought some one asked the question if the bumpers are modified by the coach builder or GM sourced . Looks like GM supplied them with the CC and the coach builder maybe modified it little more or not?
 

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