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Hi Guys,

So I have a 71 read bumper and a 74 rear bumper. Neither is perfect but the 71 is a lot better than the 74. Been looking for an affordable 72-74 rear bumper for ages to no avail, so...

I want to mount the 71 on the 74 frame but the hardware is different. Any suggestions? I can provide pics of the bumpers if it helps. Am I missing something obvious?
 

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...Been looking for an affordable 72-74 rear bumper for ages to no avail, so...
The thing I learned about these bumpers is that they are stainless steel and do not rust. Mine was bent and had cracks in the corners. I took it to a place that does chrome, polish and other metal work and the thing came back looking like brand new. If you can find the right guy he can do amazing things with a chunk of steel.

I don't know what the differences are between '71 and '74 bumpers. Mine is a '72 and there are four studs on the body that locate to respective brackets on the bumper (two on the rear and two smaller ones at the sides)
 

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I think you would have to fabricate some brackets like the ones to go from rubber bumpers to the 71/72 bumper.
 

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I have the same issue on my 74. Already converted the fronts to eliminate the bumperettes and have a 71 rear bumper to install.

You have two options.
Remove the black rubber center from the 71 and install it on the 74, that will eliminate the bumperettes and allow you to use the existing mounts.

Fabricate brackets from 3/16" x 2" x 10" to connect the 74mounts to the 71 bumper.

I am going with the bracket solution as I had the 71 bumper polished already.
I am about 3-4 weeks away from making the brackets. I will post the details when I have them finished. Don't quite know how the will work but hope to figure it out.
 

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Hi Gary et al,

So I def don't want to just move the rubber from the 71 to 74 cuz the overall condition of the 74 is weaker. Are you going to fabricate something like this:

ST154 SPIDER 1970-82 REAR BUMPER MOUNTING BRACKET - Classic Alfa

I think that's the needed bracket, right? Two required? Why are there mounts on the sides of the 71 too?
That's a Euro-spec mount. Your bumpers are different than ours due to US Dept of Transportation import requirements. Those in your link look nothing like what's on my US spec '73 Spider.
 

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the 71 is meant to mount on two studs as shown in the classic Alfa link that extend from the rear inner valance, your car probably has two rubber plugs where these would mount. Mounting new studs would mean removing and replacing the outer rear valance. the 74 bumper mounts through pads behind the bumperette, you will have to make brackets that mount in place of the 74 and adapt to the 71. I posted the prints for that bracket somewhere on this forum.
 

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I really don't know where the thread is but it is a collection of photos and prints, a "how to" thread. I first did the brackets in 2000, by 2005 the plans had been picked up by a catalog vendor and I had lost any rights to the design, as well as sales. So the thread would be at least 5 years old. But I do not remember deleting any of the postings which had that info. I do remember one thread "Old and busted, new hotness" by John M. You might find it there.
I don't know if the catalog vendor is still passing out the plans. And I don't think I even have a set anymore. the rears are not that hard to design. Measuring from the centerline of the rear valance to the existing mounts and then to the 71 bumper mounts will give you the length of each bracket, measuring the hold off means placing the bumper against the body mounts and aligning the side mount point with the "dimple" in the rear fender. The hold off is accommodated by the bends at each mounting point of the bracket.
 

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This is a project that I will be doing in the next month or so. I do not know how it will turn out yet but I thought a few pictures would help show the different conditions.

First up is the Late S2 mounting conditions where a bumper shock is incorporated into the body. The black item is a bracket that is supposed to allow the 71 bumper to bolt onto the later S2 body via the four bolts that support the shock. There is an offset in the bracket and notice how close the face of the mount is to the rear valance.

Bump 80-1.jpg

Bump 80-2.jpg

This picture shows the condition of the 74 bumper attachment. The bumper support bracket is a rubber like cushion slipped over a single stud and secured with a nut. The 74 bumper bolts to the the two holes in the bracket. Clearly the conversion mount will not work on this . Also, the bumper mount is protruding quite a bit from the rear valence relative to the first photo.
Bump 74-2.jpg

Bump 74-1.jpg

This is an over all shot of the rear bumper mounts on the 74.
IMG_0362.jpg
 

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This is the 74 photo and it shows the condition with the rubber inserts removed. The stud is broken off in this photo. It was replaced later.

IMG_0399.jpg

The 71 bumper is secured in two locations on the back and two on the sides. Not sure if it is necessary or even how to fix a mount to the side.
Bump 71-1.jpg

Note that the approximate center to center dimensions for the 74 bumper mounts is 49-1/2" and 71 mounts is 31-1/2".

It seems like a bracket similar to the one in the above post will be required but I am not sure how to deal with the distance from the valence yet. Some test fittings will be required.

Be interested if someone has solved this issue already.
Bump 71-2.jpg


I guess the indents (dimples) on the side of the fender just ahead of the rear valence is where the mounts for the side attachments were located? Always wondered why those were there!
IMG_4366.jpg
 

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Great reference but it does not address the mounting of a 71 style rear bumper onto a 74 body.

The bracket design referenced is for the later S2 series that use the shock absorbers (4 hole mount like my first photo above and the bracket I have in the photo).

So, we are still searching for a solution. Perhaps someone who has a 74 that installed a 71 rear bumper could post some photos!:1eye:
 

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It appears to me as though those blank holes towards the center are the original mount points for the '71 and '72 and probably all of the euro bumpers. It also looks like the euro mounts pictured earlier are the same as what I have on my '72. It might be easier to use those or fabricate some (I think a bolt and nut with a couple of fender washers would probably do it) The other issue I see however is that the earlier bumpers really do need those corner supports because that's a pretty long arm of light weight stainless hanging out from the rear mounts. Those are also nothing more than studs sticking out of the lower rear panel.

You don't need to worry too much about integrity, these early bumpers are of little use other than to deflect an errant shopping cart.
 

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It appears to me as though those blank holes towards the center are the original mount points for the '71 and '72 and probably all of the euro bumpers. It also looks like the euro mounts pictured earlier are the same as what I have on my '72. It might be easier to use those or fabricate some (I think a bolt and nut with a couple of fender washers would probably do it) The other issue I see however is that the earlier bumpers really do need those corner supports because that's a pretty long arm of light weight stainless hanging out from the rear mounts. Those are also nothing more than studs sticking out of the lower rear panel.

You don't need to worry too much about integrity, these early bumpers are of little use other than to deflect an errant shopping cart.
Paul,

I think I understand your comments about the other holes in the rear valence as support for the 71 bumper. Since I just painted this car I really have no desire to start modifying the body to support a non-structural bumper. The two holes in the valence have a sheet metal back up. The right side is the back side of the wheel well and the left side is just below lip of the gas tank ledge, Not my idea of a good strong connection. If I can't make a bracket to convert from 74 to 71 I may polish the 74 and install the 71 rubber trim.

Sure would be nice to see some photos of those that have been there before us, no fun being the :beta1:

Late S2 Rear.jpg

74 Rear.jpg

74 Rear 1.jpg

74 Rear 2.jpg
 

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Discussion Starter #16
Sadly, I think I might be where Gary is at. The car is actually getting painted today (its been over a year long restore/rebuild process!!) and I don't want to put holes in it. If my 71 bumper were totally perfect I might but as it is its only somewhat better than the 74 bumper.

Probably I will just keep an eye out for a really nice 74 bumper. I keep missing em!
 

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BTW, Sweet color on your Spider Gary!!
Thanks Flydog!
It looks nice in the sun light, very subtle but classy.

You may want to see if you can locate a shop that polishes stainless steel. They will know where to go to repair or may do the repairs on the bumper them selves. In the long run it will be cheaper to have yours restored than to find a good used one.

Also, there is some residual value in your 71 bumper. Those that have 75 and newer can use the brackets to bolt right on.

I will see what I can do with the brackets but it will be a while. I will keep you posted.
 

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As I said earlier my bumper was in pretty rough shape, I had even been rear-ended at one time and this is how it looks 10 years after having it straightened, welded and polished by a shop that does that sort of stuff. I cleaned up the rubber myself.

 
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