Trunk Rehab

[Patcon]

For some of you guys who have done this, I got the old floor pan out, the seam at the inner wheelhouse is clean. I did a test fit on my floor panel. The floor pan I have is from NPD, full trunk floor pan made in Canada. The new floor pan seam seems to hit the inner wheel house at a different angle and a little lower than the old floor pan. If you lift it up to the old line then it is way off the rear frame rails. did anyone else have something similar? Also did you have to trim this panel on the passenger side or the taillight side? I was going to remove the brackets at rear hangers and blast these and reinstall them, but they seem to have a lot of spot welds. I am thinking the best thing to do is blast them in place and seal them the best I can. Thoughts?

Thanks, Charles

 

[Qcode351mach]

Charles..Kinda had the same thing...as far as the line (seam) not following the old one on the wheelhouse..You need to insure that the frame rails are where they should be height wise..with everything cut out they can & will change postion unless they are supported..if you look in my video I posted prior, you can see the gold bars under my car with threaded rods at the rear..This is my home made measuring system to insure the rails are located at the correct height as per the ford chassis dimension diagram..I knew I was going to do a bunch of structural work which is why I put the car on a dolly supported AT THE ROCKERS striaght & level front to back & side to side..It's the MOST important aspect since it establishes whats called your datum line..All the ford measurements are referanced off a datum line. I emailed mister 4x4 a chassis dimension chart pdf... pm him & ask him for a copy. You need to get the car level (measure on the bottom or top of rocker I use a digital level) front to back & then take a straight 2x4 from the left rear door jamb to the right rear door jamb (you may need to raise the 2x4 with a block the same thickness on each side to clear the tranny tunnel get it level then do the same at the front door post. You can then make the same jig i did by buying the u channel steel they sell at home depot in the electrical dept for hanging conduit. Get some threaded rod & nuts...you need 3 pointers as per the diagram..1 at the torque box...1 at the front leaf spring hanger & the 1 you really need at the end of the frame rail. The diagram shows the locations and heights..once you have it set YOU KNOW that your height is 100% Make sure you set up both sides at the same time and ensure the 2 bars are also level RIGHT TO LEFT at the front & rear. Do not worry if your trunk floor doesn't follow the old line(ford had 3/8" tolorance in the unibody) AS LONG as the body is level & rear rails are set correct ..where the floor ends up could be different but it's where it has to go since you have leveled & set the rear rails correct in relation to the rest of the frame/unibody, As far as the cutout on the floor for the wheelhouses they are not perfect & need some massaging.. Best way is to make a carboard templete of the shape (curve) of the wheelhouse & then transfer that to the floor pan..Heat the flange of the floor lightly with a propane torch & hammer dolly bend etc to the proper curve. The rear part should line up flush with the cross..You need to fit the gas tank neck & gas tank this will tell you where the floor has to go. Also make sure you x measure the rear rails from front(under where the gas tank goes) to rear to insure the rails are square.

Hopes this helps

Scott

 

[Patcon]

Scott,

Yeah, that's a good start I will try to PM Mister 4x4 for the assembly drawing. I understand all the layout and level since I build for a living. I will pull some more info togethor and go from there.

Thanks, Charles

 

[Patcon]

Scott,

Is this the drawing you are working off of? I found these online...

http://429mustangcougarinfo.50megs.com/framedimensions1.jpg

http://www.nzmustang.com/TechData/71%20Mustang%20chassis%20spec.jpg

Did they have dimensions for the exterior sheet metal also?

Thanks, Charles

 

[Qcode351mach]

Scott,

Is this the drawing you are working off of? I found these online...

http://429mustangcougarinfo.50megs.com/framedimensions1.jpg

http://www.nzmustang.com/TechData/71%20Mustang%20chassis%20spec.jpg

Did they have dimensions for the exterior sheet metal also?

Thanks, Charles

No, but you can use them..I havn't found any meaurements for the exterior sheet metal..I just asked members on some other board for measurements but the response sucked..Only 1 person responded..So I did the next best thing & went to a few local car shows, finally found a car & the owner was kind enough to let me spend some time taking pics & measurements

 

[Patcon]

Scott,

I got the drawing from mister4x4. I set the car level at the rockers and level left to right. I then started checking dimensions aginst the drawing. I didn't really get anything to match those dimesions. It is like the datum line is not supposed to be level front to back. The dimensions at the rear of the car are too great by several inches and the dimensions at the front are too small by several inches. I started by checking the frame rail at the front of the floor board (6") and the hole at the rear of the floor board (6 1/2") with the rockers level the rear hole was too high by an inch or more. If I set them to what the drawing says, my dimensions may be right but the rockers will not be level front to back. What am I missing?:huh:

Charles

 

[Qcode351mach]

Scott,

I got the drawing from mister4x4. I set the car level at the rockers and level left to right. I then started checking dimensions aginst the drawing. I didn't really get anything to match those dimesions. It is like the datum line is not supposed to be level front to back. The dimensions at the rear of the car are too great by several inches and the dimensions at the front are too small by several inches. I started by checking the frame rail at the front of the floor board (6") and the hole at the rear of the floor board (6 1/2") with the rockers level the rear hole was too high by an inch or more. If I set them to what the drawing says, my dimensions may be right but the rockers will not be level front to back. What am I missing?:huh:

Charles

Charles, You have the pointers at the wrong locations...Look at x on the legend..(left side with letters) the front pointer has to touch ON the frame rail right in front of the tab where the torque box is (about an inch or less back from where the bend is, look at the side view..Make sure your only on the rail & not the part where you have 2 layers (the torque box & frame rail) The tip of the rear pointer (6.5") has to be centered in the front leaf spring hanger bolt hole (not the rear of the floor board) Is the leaf springs & rear still in the car ?

Scott

 

[Patcon]

I am very close to that location at the front. I would have to go out and measure in the shop. Yes, I was measuring to the centerline of the hole for the leaf spring (the car is totally stripped), but the error I was getting on the dimensions is too large to be caused by a thickness of sheet metal. Dimension A was off by maybe 2" (too small) dimesion C was too large by 2" or so. That kind of error in 4' or 5' would take a pretty good change at the rear shackle. What I am trying to say is if I set the X locations per the drawing the rocker panel is not going to be anywhere near level not even near the lines. I assume the dimensions are the same or close for a 73' car?

Charles

 

[Qcode351mach]

I am very close to that location at the front. I would have to go out and measure in the shop. Yes, I was measuring to the centerline of the hole for the leaf spring (the car is totally stripped), but the error I was getting on the dimensions is too large to be caused by a thickness of sheet metal. Dimension A was off by maybe 2" (too small) dimesion C was too large by 2" or so. That kind of error in 4' or 5' would take a pretty good change at the rear shackle. What I am trying to say is if I set the X locations per the drawing the rocker panel is not going to be anywhere near level not even near the lines. I assume the dimensions are the same or close for a 73' car?

Charles

Wow that is off...any chance you could snap a pic so I could see the measureing set up ? Something is not right...Are you using a steel bar to set the pointers on ? Or did you set up a level string parallel to the rockers ?

The specs are the same 71-73

 

[Patcon]

What I did is set the car to an arbitrary level,

The front measured 16 1/2 off the floor to the bottom of the torque box 16 3/4 to the bottom of the frame rail under the floor board right behind the vertical torque box seam

the floor in my shop is pretty flat, at least in these short distances. That means that all of my measurements are 10 3/4" larger when compared to the drawing.

The shackle hole is 19 5/8" or (-10 3/4") 8 7/8" it should be 6 1/2 per the drawing

Dim A 21 3/8" - 10 3/4"= 10 5/8" should be 12 3/8" (off 1 3/4")

Dim B 21 3/8" - 10 3/4" = 10 5/8" should be 11 3/4" (off 1 1/8")

X @ shackle 19 5/8" - 10 3/4"= 8 7/8" should be 6 1/2" (off 2 3/8")

Dim C 28 3/8" - 10 3/4" = 17 5/8" should be 14 3/4" (off 2 7/8")

Dim L 25 3/4" - 10 3/4" = 15" should be 11 3/16" (off 3 13/16")

Now bear in mind that the door sill and the under side of the rocker are dead level "centered between the lines" , but looking at the dimensions it looks like the the whole front needs to go up ( more as you go forward) and the rear from the front of the floor rearward needs to go down ( more the further back you go). If I adjust though the rocker will not run parallel to the datum line (ie the floor), should it?

Thanks for the help,

Charles

 

[Qcode351mach]

What I did is set the car to an arbitrary level,

The front measured 16 1/2 off the floor to the bottom of the torque box 16 3/4 to the bottom of the frame rail under the floor board right behind the vertical torque box seam

the floor in my shop is pretty flat, at least in these short distances. That means that all of my measurements are 10 3/4" larger when compared to the drawing.

The shackle hole is 19 5/8" or (-10 3/4") 8 7/8" it should be 6 1/2 per the drawing

Dim A 21 3/8" - 10 3/4"= 10 5/8" should be 12 3/8" (off 1 3/4")

Dim B 21 3/8" - 10 3/4" = 10 5/8" should be 11 3/4" (off 1 1/8")

X @ shackle 19 5/8" - 10 3/4"= 8 7/8" should be 6 1/2" (off 2 3/8")

Dim C 28 3/8" - 10 3/4" = 17 5/8" should be 14 3/4" (off 2 7/8")

Dim L 25 3/4" - 10 3/4" = 15" should be 11 3/16" (off 3 13/16")

Now bear in mind that the door sill and the under side of the rocker are dead level "centered between the lines" , but looking at the dimensions it looks like the the whole front needs to go up ( more as you go forward) and the rear from the front of the floor rearward needs to go down ( more the further back you go). If I adjust though the rocker will not run parallel to the datum line (ie the floor), should it?

Thanks for the help,

Charles

I understand what you did Charles...In theory that should work but doesn't in the world of lining up unibody cars.. You need to have at least 2 known GOOD measuring spots to set the bar to, Which estabishes the other measurements out from the known good points. Unless the car took a major hit those points would be x-6 & x 6 1/2..I don't know if you have ever seen a state of the art "frame rack" But the first step in any unibody repair is to set the car up on the machine or rack which is the datum line..It's done by clamping the car at the rocker on the pinch welds at all 4 corners...Then the measureing system ...straight bars or some systems use a jig in the shape of the frame rail is set to spec chart. Your floor may not be as level as you think. Pretty level is not good enough when doing this type of work (When I worked for Bmw we had a tolorence of + or -3mm!) There's 2 ways to do this..You have the car fully level..You can do it the way I did with a straight bar & pointers ala a true unibody measureing system..or you can try & rough it with a string..Try this: measure the first location A 12-3/8 DOWN from the frame rail to the string (set a jackstand in front to tie the end of the string to) then go to point C & measure down 14-3/4 & set the string the same way with a jack stand behind the measurement..See what you get at X-6 & X-6 1/2 from the points to the string...You may also be able to do it with a laser level / line.

 

[FastE]

I've never actually seen a completed trunk, and I'm wondering how the trunk actually goes together. Currently, mine is just a piece of rusty sheet metal laying on top of the frame rails and gas tank, with nothing on the sides obstructing the view of the ground.

I know you can get the trunk floor pan and drop-down panels, but it just seems to me that there's more to the trunk than just those three pieces of sheet metal (otherwise, stuff would roll off the trunk pan and just fall out between the quarter panel skins and drop-down panels.

Anybody got some nice pictures of what a trunk should look like? The Body Assembly Manual doesn't cover the trunk very well at all.

Thanks in advance.

Some pictures of my trunk about a week ago.This is the way,very close,to the way it looked new.The only thing not correct,is the chrome plated latch handels for the fold down area and I brought my spatter paint up higher than the factory.Everything else is as it was new.

I have more pictures under My pictures in my profile.

I will be waiting to see if I get any questions on this one.:idea:

 

[FastE]

I've never actually seen a completed trunk, and I'm wondering how the trunk actually goes together. Currently, mine is just a piece of rusty sheet metal laying on top of the frame rails and gas tank, with nothing on the sides obstructing the view of the ground.

I know you can get the trunk floor pan and drop-down panels, but it just seems to me that there's more to the trunk than just those three pieces of sheet metal (otherwise, stuff would roll off the trunk pan and just fall out between the quarter panel skins and drop-down panels.

Anybody got some nice pictures of what a trunk should look like? The Body Assembly Manual doesn't cover the trunk very well at all.

Thanks in advance.

Some pictures of my trunk about a week ago.This is the way,very close,to the way it looked new.The only thing not correct,is the chrome plated latch handels for the fold down area and I brought my spatter paint up higher than the factory.Everything else is as it was new.

I have more pictures under My pictures in my profile.

I will be waiting to see if I get any questions on this one.:idea:

No questions?

 

[71_badmach]

Just a comment, I think that's the cleanest trunk I've ever seen!

 

[Mister 4x4]

No questions?

Nope... just a puddle of drool.

 

[Patcon]

I used a string and lined it up with the datum points at the front frame rail and the front shackle hole of the rear suspension. Two jack stands at each end of the car with 45 lb olympic plates to hold them still. Most dimensions are pretty close. The rear frame rails are low and they will move up. I am concerned that if I lift them to the correct location the floor pan may be too high to the taillights, ans I am not sure the inner wheel house will hold them up and still. The front frame rail is good until near the end it is a little too high. Nothing on the car appears bent or wrinkled. One question I had was regarding tolerances. How exact were they when they set the intial datum points. An 1/8" tolerance on the two points would probably make all of my points with in an 1/8". The 3mm +/- mentioned earlier is an 1/8" roughly. The +/- would give a 1/4 range of variation over the car. It seems to me it is more important that the car is the same left to right versus matching the drawing front to back. Front to back would affect stance; left to right could affect handling, suspension travel and tire wear. Thoughts? Info? It seems like the cars were not critically toleranced if it looked good and rolled fairly straight it moved on down the line.?

Thanks, Charles

 

[Qcode351mach]

I used a string and lined it up with the datum points at the front frame rail and the front shackle hole of the rear suspension. Two jack stands at each end of the car with 45 lb olympic plates to hold them still. Most dimensions are pretty close. The rear frame rails are low and they will move up. I am concerned that if I lift them to the correct location the floor pan may be too high to the taillights, ans I am not sure the inner wheel house will hold them up and still. The front frame rail is good until near the end it is a little too high. Nothing on the car appears bent or wrinkled. One question I had was regarding tolerances. How exact were they when they set the intial datum points. An 1/8" tolerance on the two points would probably make all of my points with in an 1/8". The 3mm +/- mentioned earlier is an 1/8" roughly. The +/- would give a 1/4 range of variation over the car. It seems to me it is more important that the car is the same left to right versus matching the drawing front to back. Front to back would affect stance; left to right could affect handling, suspension travel and tire wear. Thoughts? Info? It seems like the cars were not critically toleranced if it looked good and rolled fairly straight it moved on down the line.?

Thanks, Charles

Charles,

Next step..Put the rear rails where they belong...Cut a 2x4 etc. to fit under the rear rails to hold the height..SET UP BOTH strings on each side of the car...place 1 level or take reading from left to right at X-6 1/2....Then do the same at the rear of the rails...They should match...Check for square by the X method..Fit trunk floor...Screw trunk floor to rails & rear crossmember in a few spots using self tapping sheet metal screws..Put a few on the trunk floor lap joint to the inner wheelhouse...make all your marks for your spot welds..Fit rear body panel & screw in...Fit trunk lid...disasemble...prep for welding...reasemble(just use the holes from the sheet metal screws & screws to line up everything) triple check measurements..Tack in...Check measurements...WELD IT UP

1/8 " is within tolerance..Perfect..Rail height will affect stance as will left to right(Car sits lower on one side) Whats most important is square from front susp mounting points to rear susp axle mounting points..

 

[FastE]

Great info on how to true up the back.I consider myself very lucky by having a car with no issues! I have had a couple that were night mares,67 S code fast back,back rails were shot and 73 vert that the front rails were rusted and bent.Thats anothe rstory1

Thanks for the compliments on the trunk! I realize now by looking at the pictures that I have alot of dust buils up and some touch up painting to do!

The part that I am refering to is the mat.Remember the Mach 1s "did not get a mat from the factory." Right ? I say that some did or may have.

 

[Patcon]

I got the rear trunk crossmember welded back in



I then laid the trunk floor in. There is some excess floor hanging over the rear of the floor crossmember. What do I do with that? Fold it down? Trim it off? Lap it onto the taillight panel? I reinstalled the old taillight panel to see how things go back. There was so little trunk left on disassembly I am not sure how this comes together...







How do you like the bondo repair in the left rear tailight? A little screen, a little bondo and voila a "restored" tailight hole... :dodgy:

The old tailight panel rides low enough behind both tailights, in the middle the tailight panel humps up and I don't understand how the floor should meet up. Also on the outside the lower edge of the tailight panel laps down over the back of the floor crossmember. There were spot welds here holding the tailight panel. The old spot welds are pretty low on the crossmember. Should I just move my welds up or is there something I am missing here? :huh:



You can see the crossmember through the old spot weld holes. It doesn't come but halfway down the hole. Where to from here?

Thanks, Charles

PS: Here is my Datum line rig

 

[73vertproject]

Looks like good work from here, Charles. I'm glad to see you're using official Mustang equipment for you datum line and body panel supports .

Doc