How to lower the back of your hood or trunk.
I have seen this come up on forums for so long and lately there seems to be a run on it so I felt the need to explain this a little different.
There are a number of different hood hinge designs, but they all follow in basically the same general geometry.
Be it this 1965 GM A body.
This 1959 Rambler.
Or this 2003 Dodge Caravan which has only one part and one pivot.
They all follow the same basic geometry in that the pivot point is moved back behind and below the hoods top surface line.
As you can see by my crude drawings I too am in the dark about the exact geometry that is at play in these old hinges but I have the basic idea. Where the exact intersection (pivot point) I don’t know but it is something like this.
On my wife’s family truckster (the Caravan) it is very simple, here is the hinge with the hood lowered.
If you were to add a shim between the hinge and the hood on the front bolt like this. It effectively forces the hinge to go down lower right?
When you add a shim between the hood and front of the hinge the hinge is then forced to go down further because the front of the hood will only go so far right?
You can see by this drawing with my paper hinge how when it lowers further like if it is pushed by a shim, it lowers the rear too. You can clearly see that in this model, it IS lower at the rear.
Which results in the hood going down at the rear!
In both of these photos the hood is fully latched at the front and no other adjustments were made.
Now, I understand this is a last resort, you don’t want shims showing under your hood. I don’t think it is that big of a deal being there are a whole stack of them at your fender bolts not ten inches away, but they didn’t have them there from the factory so many of us don’t want one there now.
The solution is to rotate your hinge back. Lifting the front higher and lowering the rear. If you wanted to go as far as you could as an example you would loosen all the bolts on the hinge and with the hood open simply push it up in the front opening it as far as it will go while someone tightens the bolts to the fender. At that point the rear of the hood is going to be as low as you can get it without hogging holes in the hinge or shims. Notice how this will make the hinge go further down just as it did on the wife’s truckster hinge.
If you want to go further without a shim you would need to enlarge the lower portion of the front hole and the upper portion of the rear holes in your hinge where it bolts to the fender. Then you can repeat the pushing up on the front of the hood to lower the back.
Just part of the dance you often need to do to fit body panels. This information is more about understanding the geometry than anything else. Sure you could open up holes you can add shims but if you understand the geometry you can also understand that bending the hood or trunk structure or hinge if it’s designed like the wife’s truckster or the trunk hinge on your Mustang or Chevelle you can also lower it that way. But I’ll tell you what, if you understand the geometry and stick a shim in there to see and it fits, you are way ahead of the game, now you may choose to bend something or open a hole for more movement.
I have seen this come up on forums for so long and lately there seems to be a run on it so I felt the need to explain this a little different.
There are a number of different hood hinge designs, but they all follow in basically the same general geometry.
Be it this 1965 GM A body.
This 1959 Rambler.
Or this 2003 Dodge Caravan which has only one part and one pivot.
They all follow the same basic geometry in that the pivot point is moved back behind and below the hoods top surface line.
As you can see by my crude drawings I too am in the dark about the exact geometry that is at play in these old hinges but I have the basic idea. Where the exact intersection (pivot point) I don’t know but it is something like this.
On my wife’s family truckster (the Caravan) it is very simple, here is the hinge with the hood lowered.
If you were to add a shim between the hinge and the hood on the front bolt like this. It effectively forces the hinge to go down lower right?
When you add a shim between the hood and front of the hinge the hinge is then forced to go down further because the front of the hood will only go so far right?
You can see by this drawing with my paper hinge how when it lowers further like if it is pushed by a shim, it lowers the rear too. You can clearly see that in this model, it IS lower at the rear.
Which results in the hood going down at the rear!
In both of these photos the hood is fully latched at the front and no other adjustments were made.
Now, I understand this is a last resort, you don’t want shims showing under your hood. I don’t think it is that big of a deal being there are a whole stack of them at your fender bolts not ten inches away, but they didn’t have them there from the factory so many of us don’t want one there now.
The solution is to rotate your hinge back. Lifting the front higher and lowering the rear. If you wanted to go as far as you could as an example you would loosen all the bolts on the hinge and with the hood open simply push it up in the front opening it as far as it will go while someone tightens the bolts to the fender. At that point the rear of the hood is going to be as low as you can get it without hogging holes in the hinge or shims. Notice how this will make the hinge go further down just as it did on the wife’s truckster hinge.
If you want to go further without a shim you would need to enlarge the lower portion of the front hole and the upper portion of the rear holes in your hinge where it bolts to the fender. Then you can repeat the pushing up on the front of the hood to lower the back.
Just part of the dance you often need to do to fit body panels. This information is more about understanding the geometry than anything else. Sure you could open up holes you can add shims but if you understand the geometry you can also understand that bending the hood or trunk structure or hinge if it’s designed like the wife’s truckster or the trunk hinge on your Mustang or Chevelle you can also lower it that way. But I’ll tell you what, if you understand the geometry and stick a shim in there to see and it fits, you are way ahead of the game, now you may choose to bend something or open a hole for more movement.