Repro taillight panel fit

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Jul 21, 2012
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South Florida
My Car
'71 Mustang Mach 1 M-code "Soylent Green"
'69 Plymouth Valiant 100
'68 Plymouth Satellite
Question:

Most of the problems I encountered with end cap fit on my car - following a temporarily failed attempt at taillight panel replacement - was caused by the lens flange of the panel sitting too far upwards, causing the end cap to run into it.

Most of this issue was tracked to the corner filler panel that holds the weatherstripping channel, but part of the contribution was the way the panel fit - the left hand flange of the taillamp panel kept interfering with the left-hand quarter panel. I had to grind a bit to make it fit, and even then, I felt the panel sat too far right.

That said, I'd been a bit concerned about this problem - and whether the rear quarters were sitting narrower than they should. That was before I cut up a '73 Sportsroof recently, which had been the recipient of a replacement taillight panel.

Poorly-installed panel on top, my salvaged repop on the bottom:

6ekzfs.jpg


Said '73 Sportsroof was hacked pretty badly, but it still retained enough of the original quarters to assure that the distance between them remained stock. Imagine my surprise when I found out the PO had chopped a good 1/8" - if not more - of metal from the LH taillight panel flange.

It is with this said that I'd like to ask: Have others that have replaced the taillight panel on a Sportsroof/Mach 1 found it equally necessary to grind off part of the left-hand side mounting flange? Is this generally acceptable with the repop taillight panels?

I'm tempted to say yes, seeing the amount of massaging I've seen repop panels go through, but I'm curious to hear it from those who've done it.

-Kurt

 
Mine seemed to go in without to much trouble, it required a little "fitting" but nothing to extreme.
What type of "fitting," may I ask? Near as I can figure it, only left-right adjustment is easily attainable after shaving the edges of the taillight panel. Otherwise, the weatherstripping channels force you into a fixed vertical alignment.

-Kurt

 
Question:

Most of the problems I encountered with end cap fit on my car - following a temporarily failed attempt at taillight panel replacement - was caused by the lens flange of the panel sitting too far upwards, causing the end cap to run into it.

Most of this issue was tracked to the corner filler panel that holds the weatherstripping channel, but part of the contribution was the way the panel fit - the left hand flange of the taillamp panel kept interfering with the left-hand quarter panel. I had to grind a bit to make it fit, and even then, I felt the panel sat too far right.

That said, I'd been a bit concerned about this problem - and whether the rear quarters were sitting narrower than they should. That was before I cut up a '73 Sportsroof recently, which had been the recipient of a replacement taillight panel.

Poorly-installed panel on top, my salvaged repop on the bottom:

6ekzfs.jpg


Said '73 Sportsroof was hacked pretty badly, but it still retained enough of the original quarters to assure that the distance between them remained stock. Imagine my surprise when I found out the PO had chopped a good 1/8" - if not more - of metal from the LH taillight panel flange.

It is with this said that I'd like to ask: Have others that have replaced the taillight panel on a Sportsroof/Mach 1 found it equally necessary to grind off part of the left-hand side mounting flange? Is this generally acceptable with the repop taillight panels?

I'm tempted to say yes, seeing the amount of massaging I've seen repop panels go through, but I'm curious to hear it from those who've done it.

-Kurt
I had to grind some of the left side on a N.O.S. panel & I also had to grind some of the upper right corner (for level) Do what ever it takes to get the taillights centered in the opening & LEVEL to the frame..you can measure from one corner of the qtr end cap to the INNER edge of the tailight panel..

 
I had to grind some of the left side on a N.O.S. panel & I also had to grind some of the upper right corner (for level) Do what ever it takes to get the taillights centered in the opening & LEVEL to the frame..you can measure from one corner of the qtr end cap to the INNER edge of the tailight panel..
That's good enough for me - so much for the fear of hacking into replacement panels for fit.

One thing though: You mention getting the panel level to the frame, and to the end cap corners - but what if one levels the panel to the cap corners, only for the panel to match up with the frame crossmember 3mm higher or lower on one side than the other? At present, my panel is more or less aligned with the crossmember, but the RH lamp opening is too high up - but it's also too far to the right.

I'd have no problem getting the panel to fit farther to the left, but getting it down (ignoring the weatherstripping channel's present position, which is questionable) would place the panel about 3-4mm lower in respect to the crossmember than the other side.

I've purposely stuck my fingers under the valance of all the '71-73 Mustangs I've come across since (or looked in the trunk to check the mating height between taillight panel and trunk), and I've found that I'm not alone either - and most cars with replacement panels have the bumper mount reinforcement depressions sitting a bit lower than factory. We can't all have bent frames.

Shitty factory workmanship?

As always, thanks for the assist, Q.

-Kurt

 
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Mine seemed to go in without to much trouble, it required a little "fitting" but nothing to extreme.
What type of "fitting," may I ask? Near as I can figure it, only left-right adjustment is easily attainable after shaving the edges of the taillight panel. Otherwise, the weatherstripping channels force you into a fixed vertical alignment.

-Kurt
It's been a couple of years since I installed it but seem to recall a very minimal amount of grinding was required to get everything to fit flush and even.

 
Heres what you can do with out a frame machine to level the chassis..Its the driveway method..Put a level under the front suspension motor mount crossmember..get the car level..leave that level attached at the front..drop the gas tank..get a 4foot level at the rear as close as possible to the rear shackle mounts spanning the 2 frame rails..that should read level same as the front..if not..then jack shim etc..so that both levels match..you are now ready to install the rear body panel LEVEL TO THE OTHER LEVELS..Thats where it has to go..there will be some PLAY movement in the rear crossmember just make sure if you move it, it doesn't affect the level of the frame rails..clamp it screw it..install lights & rear bumper to check..doesn't mater how much space there is at the lower flange edge from side to side..the panel should be level to the other levels..& centered left to right in the opening..You may also need to adjust the trunk lid rear weatherstrip rain channel..this why you screw clamp fit EVERYTHING FIRST

 
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I used a repop tail light panel as well - and it went in with hardly any adjustment weirdness whatsoever. I guess I got lucky in that the river mine was found in must've been somehow stayed level. ;) :D

 
Before I reply to Q:

I'm not sure which "cheap repop" everyone is talking about. Far as I know, there are only two options - one that NPD sells for $124.95, and another that is listed as "Improved repro, thicker metal, new tooling" for $189.95. I ordered the latter for my car, and it doesn't differ from the repop that I pulled off a junk '73 - and the repair on that car was at least 2 years old - nor have I seen an immediate difference in any of the repops photographed here on the forum.

Of the two I have, both have a bulge in the stamping at the top left corner of the RH taillight where the crease in the taillight feature line does not take during stamping:

148gn40.jpg


It's definitely from the same tooling, and every single repop I've seen used on this forum looks like it, including imusa76's "cheap" repop:

attachment.php


Others:

http://i45.tinypic.com/9pqmox.jpg

http://i349.photobucket.com/albums/q371/MikesStangs/73%20Mustang%20at%20Precision%20Auto%20Body/DSCF6867.jpg

This doesn't seem to be the case on NOS panels:

$_3.JPG


So what IS the cheap repop panel? Or is everyone simply referring to all repops as "cheap?"

Heres what you can do with out a frame machine to level the chassis..Its the driveway method..Put a level under the front suspension motor mount crossmember..get the car level..leave that level attached at the front..drop the gas tank..get a 4foot level at the rear as close as possible to the rear shackle mounts spanning the 2 frame rails..that should read level same as the front..if not..then jack shim etc..so that both levels match..you are now ready to install the rear body panel LEVEL TO THE OTHER LEVELS..Thats where it has to go..there will be some PLAY movement in the rear crossmember just make sure if you move it, it doesn't affect the level of the frame rails..clamp it screw it..install lights & rear bumper to check..doesn't mater how much space there is at the lower flange edge from side to side..the panel should be level to the other levels..& centered left to right in the opening..You may also need to adjust the trunk lid rear weatherstrip rain channel..this why you screw clamp fit EVERYTHING FIRST
I tried something similar to that for a different measurement, but I never thought to level the car in the manner you describe. Will do so.

However, I'm still not clear on taillight panel overall height. I know it has to clear the end caps and fit in the weatherstrip channels right, but it's the bottom that has me worried.

The panel that was in my car (an original '73 Ford service replacement, P/N sticker and all - note that the bodyshop put pop rivets in the holes for the '73 bumper filler) sat level with the trunk at the location of the bumper mount depressions - see this cutaway from the teardown discussions:

Disregard comment about crossmember length

71_mustang_crossmember_1.jpg


By comparison, the reproduction panel - even on the LH side, where the taillight lens opening is sitting properly in relation to the trunk and end cap - is sitting at least 4mm lower than the trunk floor, at the same place where the Ford panel was otherwise level:

28bxxtg.jpg


It is impossible for the taillight panel to go UP any further, which leaves all the question marks directed to the crossmember, trunk floor, and frame rails.

I know I installed the crossmember correctly and the frame was jigged for the job to prevent the rails from moving up and down against each other. I would find it very difficult to believe that the frame rails bent upwards during this job, or for the mere reason that the taillight panel was removed. Too many people on this forum have done the taillight panel with the unibody on the ground - on wheels - without encountering the difference.

Thing is, the discrepancy in the trunk also comes with this oddity:

9awl1v.jpg


The taillight panel isn't high enough for the flange to cover the holes entirely. I'm starting to think every fit issue encountered here may be due to the shortcomings of the reproduction crossmember. Below is an original, cut out of that same '73 I've been talking about:

2efnhvr.jpg


The flange of the crossmember - besides being paper-thin - is at least an 1-1/4" tall at the taillight panel flange (scrapped the panel since, so I can't measure it anymore). By comparison, the repop doesn't appear to be longer than 3/4" at the same location:

71_mustang_105.jpg


Remember I also suspected that the repro rear crossmember rear edge was 1/4" too short to meet the taillight panel at the rear flange properly? An examination of that '73 original proved such. The 1/4" is lost due to the thicker steel of the repop - the thicker steel steals 1/8" of metal between the two 90 degree bends that form the rear bends. It's crucial for proper taillight panel fit.

Original measures approximately 25mm between bends:

de214o.jpg


The repop isn't thin enough that it can be twisted and bent at the edges as seen on this one. It's enough for a 5mm discrepancy.

I think it's safe for me to stop worrying and simply plug weld the taillight panel to the flange with a couple of extra holes higher up if necessary. What do you say, Q?

-Kurt

 
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What I say is screw the panel on where you think it should be..Put the bumper on..& the rear bumper reinforcements inside the trunk..The bumper will pretty much dictate tell you the height of the panel..The one thing I have noticed about the repops I have seen held in my hand..The taillight opening is about an 1/8" LARGER all the way around..Take a taillamp & install it in the opening..then do the same in a n.o.s. panel..

 
What I say is screw the panel on where you think it should be..Put the bumper on..& the rear bumper reinforcements inside the trunk..The bumper will pretty much dictate tell you the height of the panel.
Figured as much. Coming up too low every time is my worry.

The one thing I have noticed about the repops I have seen held in my hand..The taillight opening is about an 1/8" LARGER all the way around..Take a taillamp & install it in the opening..then do the same in a n.o.s. panel..
All I needed to hear. I'm going to get an NOS panel; screw the repops.

-Kurt

 
What I say is screw the panel on where you think it should be..Put the bumper on..& the rear bumper reinforcements inside the trunk..The bumper will pretty much dictate tell you the height of the panel.
Figured as much. Coming up too low every time is my worry.

The one thing I have noticed about the repops I have seen held in my hand..The taillight opening is about an 1/8" LARGER all the way around..Take a taillamp & install it in the opening..then do the same in a n.o.s. panel..
All I needed to hear. I'm going to get an NOS panel; screw the repops.

-Kurt
Keep in mind you are working with a 40 year old car that was

rusted and / or wrecked before and a taillight panel replaced.

Then it was wrecked / rear ended HARD on the frame rail

It's bent - these cars bend easy

As you removed the quarter, the trunk floor, the rear cross member it probably all relaxed from when it was hit.

 
Keep in mind you are working with a 40 year old car that was

rusted and / or wrecked before and a taillight panel replaced.

Then it was wrecked / rear ended HARD on the frame rail

It's bent - these cars bend easy

As you removed the quarter, the trunk floor, the rear cross member it probably all relaxed from when it was hit.
+1 that car was hit pretty hard on the right rear..As I said before.. the frame unibody measurements should be confirmed on a frame machine before any new panels go on..Would be the best $250.00 you spent..Piece of mind priceless

 
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Yeah... that's good point.

Honestly though, it doesn't look all that far off. The center most portions of the trunk surround weatherstripping channels on both sides need to be tapped down into place - moreso on the passenger side than the driver side, but that might also be a by-product of the accident.

I'd be tempted to install the tail lights, end caps, and close the trunk - see how far off it is then. You might be surprised.

 
Keep in mind you are working with a 40 year old car that was

rusted and / or wrecked before and a taillight panel replaced.

Then it was wrecked / rear ended HARD on the frame rail

It's bent - these cars bend easy

As you removed the quarter, the trunk floor, the rear cross member it probably all relaxed from when it was hit.
Wrecked once at the back; the first taillight panel was replaced due to rust.

When the trunk floor was removed, a temporary crossmember was welded onto the top of the rails. It didn't have that much of an opportunity to flex.

+1 that car was hit pretty hard on the right rear..As I said before.. the frame unibody measurements should be confirmed on a frame machine before any new panels go on..Would be the best $250.00 you spent..Piece of mind priceless
If it was hit that hard, the framerail would have crumpled more than it did. It does have a warp mark above the rear axle, but it was pulled out afterwards by the PO.

Last time I measured the car (jacked the rear frame rails level on a level surface, then measured the rear rails straight down), they came out identical.

-Kurt

 
Try not to ever think it, the workers on the line in the 70's did a great job building our cars but lets be honest, they weren't building rockets for NASA so tolerences could be off a bit even from the factory;)

 
Try not to ever think it, the workers on the line in the 70's did a great job building our cars but lets be honest, they weren't building rockets for NASA so tolerences could be off a bit even from the factory;)
Yep - and I think about that whenever anything is slightly off. Convincing myself of that when putting the car back together is the hard part.

-Kurt

 
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