hood bowed - how to adjust questions

[rjpohl]

The hood is high in the middle (front to back) on both sides.  This is a new hood from Kentucky Mustang.  It fits pretty good in the rear and front in relation to fender height.   Basically the hood is bowed up along both edges.  Do I need to shim fenders up or is there a way to take some bow out of the hood (hopefully not damaging paint).

thanks

Bob

 

[droptop73]

I have the same issue with the new hood. My plan is to try shimming the fenders. If I had seen this before it was painted I would have tried to tweak the hood a bit.

 

[turtle5353]

This is very common in the new dynacorn aftermarket hoods. It would of been alot easier to fix when the panel was being fitted before paint, but i believe you can still persuade it to the arch you need after paint. I don't believe shimming the fenders in the middle will get the job done. You will be putting alot of stress on the center of the fenders to try to get them to arch up to meet the hood. The fenders aren't made to bend that way. The way the lip is formed on the fender would be very hard to make it bow.

The factory hoods arch fit very nicely. the aftermarket ones, not so much. The factory hoods pinch seam was much better than the aftermarket ones. The aftermarket  pinch seam between the upper panel and lower panel are loose enough to allow for adjustment of the arch.  Again this should of been done before paint. you would of re-arched the hood to match the fenders, then tack welded the pinch seam under the hood to keep the panels from flexing back. then ground down the tack welds, seam sealed the entire seam, then paint.  But since yours is already painted all is not lost. You can still re-arch the hood but be very careful with the paint. 

Mark your hood arch with a piece of tape at the highest point of the arch on each side. Measure how high above the fender it is and write it down on the tape. (1/4", 5/16", ect. whatever it is)  Then lay down on floor two 2x4's cut to width of the hood and space them so the underside of the hood will sit on the hood latch hump in front and the hump in the back of the hood. Cover 2x4's with a blanket to protect hood. Remove hood, and place on top of 2x4's. Now take a measurement from the piece of tape on top of the hood to the floor. Write it down. Now for the scary part.  Take a 2x4 wrapped in a towel or blanket and lay it lengthenwise along hood edge. Now you are going to push down on the hood and flex it downward, rotating from driver side to passenger side, or have someone on the other side helping push down on the arch. You will then want to keep taking a measurement at the tape mark to the floor till it is what you need it to be according to your original measurements that i said to write down. If you needed the arch 1/4" lower then your new measurement should be 1/4" less than the 1st hood to floor measurement you took.  If you go slow and gentle your paint should be fine. Once you have the measurements you want, install the hood and check fit.  

I hope that explanation wasn't too confusing. This is exactly how I did the hood on the yellow mach 1 I restored. Here's a few pics of how i laid it out. 

 

[71coop]

This is very common in the new dynacorn aftermarket hoods. It would of been alot easier to fix when the panel was being fitted before paint, but i believe you can still persuade it to the arch you need after paint. I don't believe shimming the fenders in the middle will get the job done. You will be putting alot of stress on the center of the fenders to try to get them to arch up to meet the hood. The fenders aren't made to bend that way. The way the lip is formed on the fender would be very hard to make it bow.

The factory hoods arch fit very nicely. the aftermarket ones, not so much. The factory hoods pinch seam was much better than the aftermarket ones. The aftermarket  pinch seam between the upper panel and lower panel are loose enough to allow for adjustment of the arch.  Again this should of been done before paint. you would of re-arched the hood to match the fenders, then tack welded the pinch seam under the hood to keep the panels from flexing back. then ground down the tack welds, seam sealed the entire seam, then paint.  But since yours is already painted all is not lost. You can still re-arch the hood but be very careful with the paint. 

Mark your hood arch with a piece of tape at the highest point of the arch on each side. Measure how high above the fender it is and write it down on the tape. (1/4", 5/16", ect. whatever it is)  Then lay down on floor two 2x4's cut to width of the hood and space them so the underside of the hood will sit on the hood latch hump in front and the hump in the back of the hood. Cover 2x4's with a blanket to protect hood. Remove hood, and place on top of 2x4's. Now take a measurement from the piece of tape on top of the hood to the floor. Write it down. Now for the scary part.  Take a 2x4 wrapped in a towel or blanket and lay it lengthenwise along hood edge. Now you are going to push down on the hood and flex it downward, rotating from driver side to passenger side, or have someone on the other side helping push down on the arch. You will then want to keep taking a measurement at the tape mark to the floor till it is what you need it to be according to your original measurements that i said to write down. If you needed the arch 1/4" lower then your new measurement should be 1/4" less than the 1st hood to floor measurement you took.  If you go slow and gentle your paint should be fine. Once you have the measurements you want, install the hood and check fit.  

I hope that explanation wasn't too confusing. This is exactly how I did the hood on the yellow mach 1 I restored. Here's a few pics of how i laid it out. 

Has anyone actually done this with a painted hood? I have the same issue. I believe that I will live with it until i see someone do this without damaging paint.

 

[turtle5353]

This is very common in the new dynacorn aftermarket hoods. It would of been alot easier to fix when the panel was being fitted before paint, but i believe you can still persuade it to the arch you need after paint. I don't believe shimming the fenders in the middle will get the job done. You will be putting alot of stress on the center of the fenders to try to get them to arch up to meet the hood. The fenders aren't made to bend that way. The way the lip is formed on the fender would be very hard to make it bow.

The factory hoods arch fit very nicely. the aftermarket ones, not so much. The factory hoods pinch seam was much better than the aftermarket ones. The aftermarket  pinch seam between the upper panel and lower panel are loose enough to allow for adjustment of the arch.  Again this should of been done before paint. you would of re-arched the hood to match the fenders, then tack welded the pinch seam under the hood to keep the panels from flexing back. then ground down the tack welds, seam sealed the entire seam, then paint.  But since yours is already painted all is not lost. You can still re-arch the hood but be very careful with the paint. 

Mark your hood arch with a piece of tape at the highest point of the arch on each side. Measure how high above the fender it is and write it down on the tape. (1/4", 5/16", ect. whatever it is)  Then lay down on floor two 2x4's cut to width of the hood and space them so the underside of the hood will sit on the hood latch hump in front and the hump in the back of the hood. Cover 2x4's with a blanket to protect hood. Remove hood, and place on top of 2x4's. Now take a measurement from the piece of tape on top of the hood to the floor. Write it down. Now for the scary part.  Take a 2x4 wrapped in a towel or blanket and lay it lengthenwise along hood edge. Now you are going to push down on the hood and flex it downward, rotating from driver side to passenger side, or have someone on the other side helping push down on the arch. You will then want to keep taking a measurement at the tape mark to the floor till it is what you need it to be according to your original measurements that i said to write down. If you needed the arch 1/4" lower then your new measurement should be 1/4" less than the 1st hood to floor measurement you took.  If you go slow and gentle your paint should be fine. Once you have the measurements you want, install the hood and check fit.  

I hope that explanation wasn't too confusing. This is exactly how I did the hood on the yellow mach 1 I restored. Here's a few pics of how i laid it out. 

Has anyone actually done this with a painted hood? I have the same issue. I believe that I will live with it until i see someone do this without damaging paint.

Back when i first got my car I did this to my hood......over 15 years ago.  Didn't hurt the paint.

I would be willing to bet you have a better chance of cracking the paint on your fender if you put enough shims under the center to bring it up to match hood.

 

[MikeGriese]

I wonder how these guys came up with their dies for making new hoods. This type of arching is typical of original hoods. They weren't made that way in the beginning - it happened over time. These cars have LOOOOONG hoods that are supported at one end by hinges that get increasingly stiff over the years as corrosion finds its way into the pivots and rivets. Every time you close the hood, you pull down on the free end, bending the hood a little bit until there is enough force on the hinges to overcome the friction and they start to close. Repeat a few thousand times and you get an arched hood.

The original standard hood on my convertible was arched almost exactly like your new hood. The fix was to support it well from underneath, protect the top surface and pound it back into shape with mighty blows from a deadfall hammer. While this was happening, I used up all of my parts locating luck and found a way underpriced NOS ram air hood that was stamped in 1973 - still in the box - within 200 miles of home. That hood required no fettling to get it to fit - it bolted up to the hinges and met the fenderline perfectly.

My guess is that these remanufacturers didn't use NOS parts for their patterns and instead used "Really Nice" OEM parts for their patterns. For a lot of things this is just fine. For the hood, clearly it's not. To fix a new hood with an arch, you may need to loosen up some welds in the superstructure underneath before the hood can be adjusted to fit.

 

[Carolina_Mountain_Mustangs]

I worked in the automotive stamping business for 20 years. The parts at the factory did not just bolt on and fit. The parts are twisted and bent to get a best fit they were never perfect.

Yes it is common to need to change the arch on the repo hoods. Not just Mustang but pretty much all makes. My friend that does restorations bends everyone he installs to get best fit. Yes you do tack weld the hem to get it to hold. He usually blocks the up and stands on them and his dad hands him bag of sand if he needs more weight. 

He also takes all of the black Ecoat off the repo parts has found rust under several of them. Just on the outside.

Some Fords actually have crush zones to allow the parts to be bent on the assembly line to fit. I have a video here someplace that actually shows them bending trunk lids to fit. 

The assembly area for doors has huge hydraulic fixture that bends and twists the doors to get better fit.

My son works at BMW and they hire big guys to fit the lift gates on their vehicles. They twist and put blocks in and bend to fit. This is a $65,000 BMW not a $3,500 - $5,000 mustang.

The reason shimming the fender will not give good results is that you have the vertical wall coming from the mounting surface to the skin of the fender. It would take lots of force to bend and kink that wall.

When they cut the repo tooling they get a NOS part but that does not mean it is a perfect part. We use to send our line rejects to Ford for service. I am sure it is and was a common practice. 

Everyone is right on that the hood has to be bent to fit. Shop should have done that before they painted. I hope they removed the black E-coat.

 

[midlife]

Another way to skin this cat is to drive the car moderately hard into a brick wall, which forces the front towards the cowl and raises the fenders a tad to accommodate the foreshortening. Not recommended for the faint of heart...

 

[turtle5353]

Another way to skin this cat is to drive the car moderately hard into a brick wall, which forces the front towards the cowl and raises the fenders a tad to accommodate the foreshortening.  Not recommended for the faint of heart...

I tried that that but I think I did something wrong!!! My hood arch is way off now!! lollerz

 

[computercarguy]

Another way to skin this cat is to drive the car moderately hard into a brick wall, which forces the front towards the cowl and raises the fenders a tad to accommodate the foreshortening.  Not recommended for the faint of heart...

No, no, no. You're thinking of headlight adjustment.  ::laugh::

 

[Vinnie]

Another way to skin this cat is to drive the car moderately hard into a brick wall, which forces the front towards the cowl and raises the fenders a tad to accommodate the foreshortening.  Not recommended for the faint of heart...

I tried that that but I think I did something wrong!!! My hood arch is way off now!! lollerz

Glad to see your sense of humour wasn't crushed

 

[delawarebill]

last month I had a body/painter come look at what I wanted to do to the hood.. paint the black out.. showed him the bubble and he said he would not touch it. I didn't have the paint code for it was a custom job yrs ago. afterwards I tried to shim the hinges but that didn't work. so I just put it on. I totally agree...FIX BEFORE PAINT.!!!!!!!!

 

[92GTS-R]

You could always get a couple of Hot ladies in Swimsuits to lay across the hood for a photo shoot?

It might flatten out the hood and better still, would entertain us with the pics

 

[1sostatic]

Another way to skin this cat is to drive the car moderately hard into a brick wall, which forces the front towards the cowl and raises the fenders a tad to accommodate the foreshortening.  Not recommended for the faint of heart...

I tried that that but I think I did something wrong!!! My hood arch is way off now!! lollerz

Glad to see your sense of humour wasn't crushed

Humor is the best medicine ...but... 

I cant look at these smacked cars without having a melt down...., I' guess I'm squeamish.

 

[rjpohl]

This is very common in the new dynacorn aftermarket hoods. It would of been alot easier to fix when the panel was being fitted before paint, but i believe you can still persuade it to the arch you need after paint. I don't believe shimming the fenders in the middle will get the job done. You will be putting alot of stress on the center of the fenders to try to get them to arch up to meet the hood. The fenders aren't made to bend that way. The way the lip is formed on the fender would be very hard to make it bow.

The factory hoods arch fit very nicely. the aftermarket ones, not so much. The factory hoods pinch seam was much better than the aftermarket ones. The aftermarket  pinch seam between the upper panel and lower panel are loose enough to allow for adjustment of the arch.  Again this should of been done before paint. you would of re-arched the hood to match the fenders, then tack welded the pinch seam under the hood to keep the panels from flexing back. then ground down the tack welds, seam sealed the entire seam, then paint.  But since yours is already painted all is not lost. You can still re-arch the hood but be very careful with the paint. 

Mark your hood arch with a piece of tape at the highest point of the arch on each side. Measure how high above the fender it is and write it down on the tape. (1/4", 5/16", ect. whatever it is)  Then lay down on floor two 2x4's cut to width of the hood and space them so the underside of the hood will sit on the hood latch hump in front and the hump in the back of the hood. Cover 2x4's with a blanket to protect hood. Remove hood, and place on top of 2x4's. Now take a measurement from the piece of tape on top of the hood to the floor. Write it down. Now for the scary part.  Take a 2x4 wrapped in a towel or blanket and lay it lengthenwise along hood edge. Now you are going to push down on the hood and flex it downward, rotating from driver side to passenger side, or have someone on the other side helping push down on the arch. You will then want to keep taking a measurement at the tape mark to the floor till it is what you need it to be according to your original measurements that i said to write down. If you needed the arch 1/4" lower then your new measurement should be 1/4" less than the 1st hood to floor measurement you took.  If you go slow and gentle your paint should be fine. Once you have the measurements you want, install the hood and check fit.  

I hope that explanation wasn't too confusing. This is exactly how I did the hood on the yellow mach 1 I restored. Here's a few pics of how i laid it out. 

Thanks for the great suggestion, I'll have to build up the courage to try it.  I definitely will not try shimming he fenders.