Correct '72 rear bumper alignmnet?
Thread Starter
Race Director
Joined: Oct 2005
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From: Camp Verde AZ
C1 of Year Finalist (performance mods) 2019
2017 C1 of Year Finalist
Correct '72 rear bumper alignmnet?
I replaced the factory rear bumpers with paragon manufactured replacements, because it was going to be a wash $$ wise, getting the old ones rechromed, after fixing all the holes someone drilled in the undersides, and shipping both ways.
The new bumpers fit perfectly, going through the original small holes in the fiberglas, and bolting to the existing brackets without any adjusting necessary.
I never paid any attention to the old bumper alignment before I took them off, other than to know they were uniform.
Now, up on the rack, at eye level, I see that the new bumpers angle down from the outside of the car, towards the center where they get close to the license plate.
Placing a straight edge across both bumpers, all the way to the outsides, i see the bumpers angle down about 1/2" on each side, uniformly on both sides, such that I get about a 1/2" shim between the top of the inside of each bumper, and the straightedge..
This is a never hit car, BTW.
Did the original bumpers have this angle down, outside to center? Or are they supposed to be level, straight across? I am somewhat disinclined to reinstall the old bumpers to check.
Making the new bumpers level, would require a lot of hole elongation,and bracket modification.
I never paid any attention to this angle issue before.
Thanks,
Doug
The new bumpers fit perfectly, going through the original small holes in the fiberglas, and bolting to the existing brackets without any adjusting necessary.
I never paid any attention to the old bumper alignment before I took them off, other than to know they were uniform.
Now, up on the rack, at eye level, I see that the new bumpers angle down from the outside of the car, towards the center where they get close to the license plate.
Placing a straight edge across both bumpers, all the way to the outsides, i see the bumpers angle down about 1/2" on each side, uniformly on both sides, such that I get about a 1/2" shim between the top of the inside of each bumper, and the straightedge..
This is a never hit car, BTW.
Did the original bumpers have this angle down, outside to center? Or are they supposed to be level, straight across? I am somewhat disinclined to reinstall the old bumpers to check.
Making the new bumpers level, would require a lot of hole elongation,and bracket modification.
I never paid any attention to this angle issue before.
Thanks,
Doug
Drifting
Joined: Jul 2002
Posts: 1,995
Likes: 110
From: Garland Texas
Hi Doug,
No the original bumpers didn't fit like that. The problem lies with the inward mounting bracket angle on the replacement bumpers. Behind the exhaust panel, attached to the frame are two brackets bolted together. These brackets are slotted. You need to loosen all the bolts and move the bumper into position. Then tighten the bolts.
The two rods that support the bottom of the bumper are also slotted. Attach these last. You may need to bend the ends to make them lay flat against the frame and the bumper.
Mike
No the original bumpers didn't fit like that. The problem lies with the inward mounting bracket angle on the replacement bumpers. Behind the exhaust panel, attached to the frame are two brackets bolted together. These brackets are slotted. You need to loosen all the bolts and move the bumper into position. Then tighten the bolts.
The two rods that support the bottom of the bumper are also slotted. Attach these last. You may need to bend the ends to make them lay flat against the frame and the bumper.
Mike
Thread Starter
Race Director
Joined: Oct 2005
Posts: 12,470
Likes: 1,548
From: Camp Verde AZ
C1 of Year Finalist (performance mods) 2019
2017 C1 of Year Finalist
Question:
As the holes through the fiberglas are only about 1/2"-5/8" in diameter, I am going to assume that the holes would need to be elongated up by about 1/2" to make the bumpers plane perfectly level.
However, there isn't enough room to move the inner brackets up that far on the inside, I can maybe move them 3/16" up, before they hit the curved portion of the rear panel.
But, I have room to move the outer rear nd side brackets down about 1/4", so it seems like moving the inner mounts up,nd outer mounts down, will make them fairly level, without a whole bunch of hole slotting.,
Does that sound reasonable?
I remember why i dislike body work and trim fitment, and prefer nicely machined assembly of motor parts.
Thanks,
Doug
As the holes through the fiberglas are only about 1/2"-5/8" in diameter, I am going to assume that the holes would need to be elongated up by about 1/2" to make the bumpers plane perfectly level.
However, there isn't enough room to move the inner brackets up that far on the inside, I can maybe move them 3/16" up, before they hit the curved portion of the rear panel.
But, I have room to move the outer rear nd side brackets down about 1/4", so it seems like moving the inner mounts up,nd outer mounts down, will make them fairly level, without a whole bunch of hole slotting.,
Does that sound reasonable?
I remember why i dislike body work and trim fitment, and prefer nicely machined assembly of motor parts.
Thanks,
Doug
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
AZDoug,
If you still have your original bumpers...you might want to remove the new ones. And here is why.
Take a VERY CAREFUL look at how the mounting stands are welded to your original bumpers versus the new ones. When these bumpers are being made...the person welding them "sometimes" does not get the mounting tabs in the EXACT correct spot prior to welding. DO NOT ASK me how I know this. I have measured and clearly seen the differences in front and rear bumpers welding and the problems in them...and if these mounting stands are not right...the bumper will be off...and regardless on how much you try to adjust the inner bumper mounting brackets...the angle of the mounting stand is wrong and can not be corrected due to how the bumper was made. I went through 4 front bumpers until I actually got one that was perfect.....and there were very clear VISUAL differences in how all of the previous ones were different. Same thing with the rears also.
Look at if the mounting stands are all the way in the bumper when they were welded...versus having a gap and weld filling in the gap.
I feel you pain and have been there before.
DUB
If you still have your original bumpers...you might want to remove the new ones. And here is why.
Take a VERY CAREFUL look at how the mounting stands are welded to your original bumpers versus the new ones. When these bumpers are being made...the person welding them "sometimes" does not get the mounting tabs in the EXACT correct spot prior to welding. DO NOT ASK me how I know this. I have measured and clearly seen the differences in front and rear bumpers welding and the problems in them...and if these mounting stands are not right...the bumper will be off...and regardless on how much you try to adjust the inner bumper mounting brackets...the angle of the mounting stand is wrong and can not be corrected due to how the bumper was made. I went through 4 front bumpers until I actually got one that was perfect.....and there were very clear VISUAL differences in how all of the previous ones were different. Same thing with the rears also.
Look at if the mounting stands are all the way in the bumper when they were welded...versus having a gap and weld filling in the gap.
I feel you pain and have been there before.
DUB
Thread Starter
Race Director
Joined: Oct 2005
Posts: 12,470
Likes: 1,548
From: Camp Verde AZ
C1 of Year Finalist (performance mods) 2019
2017 C1 of Year Finalist
With the new bumpers still on the car, i calipered the bracket mounts and compared them to the original bumpers and see no discernibly difference in how far in the bracket mounts are in relation to the bumpers, or where the bolts holes are in relation to the edge of the mounts, and since the new bumpers bolted right up to the brackets, without loosening any of the bracket bolts at all, I don't see that is an issue; if the brackets were off that far, they shouldn't have bolted up.
For all I know, the original bumpers were like this and I just never paid any attention to it.
I believe simply loosening ALL the bumper bracket bolts, and attachments to the bumper, and just shoving the bumper around will make most of the problem go away, without slotting the fiberglas for additional movement. If I can a 1/2" tilt to go to 1/8" or 3/16", I will be happy.
Even now, you don't really notice this issue when the car in on the ground and you are right behind it, but on the lift at eye level, or perhaps back 100 feet or so away, you do/would.
I am not real **** about everything being exactly perfect, like I used to be, as I realized long ago, that perfection is never quite never achieved,and attempting to achieve it, will either cost you a large pile of money, or you will go mad in the process.
Doug
For all I know, the original bumpers were like this and I just never paid any attention to it.
I believe simply loosening ALL the bumper bracket bolts, and attachments to the bumper, and just shoving the bumper around will make most of the problem go away, without slotting the fiberglas for additional movement. If I can a 1/2" tilt to go to 1/8" or 3/16", I will be happy.
Even now, you don't really notice this issue when the car in on the ground and you are right behind it, but on the lift at eye level, or perhaps back 100 feet or so away, you do/would.
I am not real **** about everything being exactly perfect, like I used to be, as I realized long ago, that perfection is never quite never achieved,and attempting to achieve it, will either cost you a large pile of money, or you will go mad in the process.
Doug
Thread Starter
Race Director
Joined: Oct 2005
Posts: 12,470
Likes: 1,548
From: Camp Verde AZ
C1 of Year Finalist (performance mods) 2019
2017 C1 of Year Finalist
I wasn't aware at the time that the brackets were as adjustable as they are. The small holes through the fiberglas would need to be tweaked some, to get perfect alignment.
Basically, the outsides are too high,and the insides too low, drop one, raise the other and it will be close.
Thanks,
Doug
Basically, the outsides are too high,and the insides too low, drop one, raise the other and it will be close.
Thanks,
Doug
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From: Charlotte NC
USA made ones. I have not encountered a problem with the foreign ones at this time.
I would have to look and see if I still have the photo's of the major issues with a new front USA bumper I had.
All I can say...is that after three front bumpers...and all of them were so off...I finally got one that was perfect.
DUB
I would have to look and see if I still have the photo's of the major issues with a new front USA bumper I had.
All I can say...is that after three front bumpers...and all of them were so off...I finally got one that was perfect.
DUB
Thread Starter
Race Director
Joined: Oct 2005
Posts: 12,470
Likes: 1,548
From: Camp Verde AZ
C1 of Year Finalist (performance mods) 2019
2017 C1 of Year Finalist
Correct alignment went very smooth and fast.
I used a pic that i believe Alan posted, which doesn't seem to be posted anymore, to figure out where the bumpers were supposed to be,and after loosening all bracket bolt, everywhere, pushed bumpers into proper place, and tightened the bumper mounting bolts first bolts, then all the bracket bolts behind the fiberglas after they had all settled into their new locations.
Thanks for the help!
Doug
I used a pic that i believe Alan posted, which doesn't seem to be posted anymore, to figure out where the bumpers were supposed to be,and after loosening all bracket bolt, everywhere, pushed bumpers into proper place, and tightened the bumper mounting bolts first bolts, then all the bracket bolts behind the fiberglas after they had all settled into their new locations.
Thanks for the help!
Doug