Trial Bonnet fitting

All the panels are loose and inside the bonnet with everything latched down and the springs compressed. Then when I go inside I make sure everything is exactly where I want it. That way when it’s glued together, it will remain exactly where I want it. If it looks like the springs are giving it way too much upward pressure and distorting the loose panels where I don’t want them, I will remove the springs and glue up without them. Without the springs, the bonnet should become one solid unit when glued and the springs can be put on with nothing moving. On a"loose" bonnet, the springs can distort the headlight baffles under pressure, so it’s a 50/50 call. I also “fondle” the outside sheet metal all over to see if any panels are pushing the metal in ways I don’t want. You can’t dolly out problems if there is a permanently glued panel under it.

Phil.

Those 2 little gussets with 4 bolts each are made to move. The holes are oval and when loosened, the rear end of the bonnet wings can be moved out and in a bit. Don’t be surprised if those little bolts are impossible to turn without breaking on an original bonnet. There’s no paint inside where the threads are and rust gets in there after 50+ years.

Phil.

thank you for explaining those “gussets” they are off and new. the entire bonnet is rust free well done i think. its very close to fitting first try. I have to redo the left side bulkhead and sill below, it was done wrong before i bought the car. the left side is unmolested so my plan is to align with the left side and across the cowl then redo the right to match. it looks do-able right now. My bonnet measure 62" at the bottom in back, same number on the car. If i knew how to post photos i’d take one for that.

One thing I can ad is that with my car, and that is not uncommon, the bonnet fit was perfect with the engine out of the car. Now after paint and the engine and gearbox were mounted, the bonnet sits slightly (maybe 1/8") off to one side. I does close and look right, it’s just not perfect. I may address the issue one day …

I am pretty much in David’s camp on this one!! With one difference !! I had my bonnet resting nose down on a trolly , and when stored off the car, it was tied. When offered up to the car, the picture frame was jacked up, supports placed, and the pivot bolts fitted. Slight movements of the bonnet on the trolly was easily done to get the exact alignment needed for the bolts to be inserted. In this way the incremental process of getting that optimum fit, involving a number of removals and replacements of the bonnet , could be done single handed. Of course the original placeing of the bonnet onto the trolly required help.

Phil. Thanks for that.

My spouse and I used the contraption in the first two photos during the initial bonnet reassembly and fitting phase. Started with the bare shell (in this photo) and used it throughout final reassembly (flanges and ducts). Think we had it on and off four times before the fit was finalized and it was deemed ready for paint. Then it went on the rolling trolley for final paint and stayed there for bumpers, lights, grill, etc. When the rest of the car was ready, I picked up the front portion with the motorcycle jack (padded with pillows) and three of us rolled it back over the chassis…one person at each rear corner and one pushing the jack. Dropped right into place on the chassis pins…about 15 minutes for three geezers. Gaps were all fine, Had to pull two shims on the hinges to get the fit where I wanted it. (I spent weeks getting the bumpers to fit and wasn’t about to risk knocking them it out of alignment by sliding it around on it’s nose).




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Eric,
Your pick up points for your spreader bar, are they thin strips of metal between the fender and center section, dead ended on the underside?
Thanks,
Ken

Ken,

They’re lengths of that perforated metal plumbers strap (two per side for safety). The lower end is secured by one of the flange bolts that join the fender/wing to center section (left out the spacer for that bolt…replaced it after last lift). Later in the process I put masking tape on either side of the straps in case of marring or chips in the final primer, but it was never an issue.

Just to shorten this, the trial fitting process is to :

( AFTER the bonnet is in epoxy primer )

Bolt wings, center section, and under panel together , then

Mount hinges in approximate position and place bonnet on car followed by

a. Get the shims correct

b. Get the left-right spacing correct on the pivots

then snug hinges, remove bonnet, glue in all flanges?

This bothers me because I want to bond in flanges, THEN epoxy prime. The exact opposite of this technique. Any other input? What am I missing? :face_with_raised_eyebrow:

When I fit the bare bonnet shell I had to do the “cargo strap squeeze” at the aft end in order to get exact alignment with the sills. Also had to lengthen the slots in the adjustment brackets at the upper rear corners to keep the proper shape. While minor, these adjustments could have impacted ideal fit of the duct work (and put stress on the shell) if the flanges had already been positioned and glued. (I positioned and glued the ducts/flanges with the previously adjusted shell off the car).

Timing of the primer can be handled any number of ways. If your concern is bonding to epoxy, I don’t believe it’s an issue. I epoxy primed the shell before assembling and fitting, then sanded and scuffed the bonding surfaces after establishing their exact location in the “adjusted” shell…could have sanded back to bare metal, but to what purpose?

Ok,

was this bonnet original to your car?

Isn’t there enough play/slop to allow the parts bolted to the flanges to wiggle enough to fit?

Yes it was, but it had been off the car and shoved around for 30 years on it’s tail end. And when it was disassembled into sections, it inevitably lost the precise original settings in spite of my having placed a few telltale markings with a file. There’s not much slop and the odds of imparting distortion is pretty high in my opinion. The ducts don’t simply float in the structure, they provide torsional rigidity.

69 Coupe -Currently being re-assembled

Good Day. This couldn’t be more pertinent to my current progress. I have just 2k Epoxy’d the inner bonnet to my 69’ and am preparing to epoxy the other components that have all been blasted, recently. (I did not blast the center section or wings, but I did sand all the way to metal) The bonnet is original to my coupe and has been off the car for 28 years, standing on it’s end.

Prior to epoxy’ing the inner bonnet, I re-installed all components and measured the sides of the wings at the firewall corners and just to the rear of the wheel-wells. Those measurements were very close to measurements from my newly installed sills at the same positions. The adjustment flanges at the base of the wings/center section will allow for approximately 1/2" movement either inward or outward when I mount onto the frame.

It is my intent to epoxy prime all components, then base/clear all, then install everything LOOSELY and then mount on the car vertically. Then I will slowly lower and check everything for clearance etc. Once I am happy with the fit/clearances, I will tighten bolts from beneath to maintain the fit. Then remove the bonnet and tighten everything. ( engine is not in the vehicle ). Some of my procedures are altered from those of others on the forum because I do everything by myself, with very few exceptions. When absolutely necessary, my wife assists. Over the years I have become adept at building jigs to serve as helpers!

I should mention that all the flanges are newly Sika-Flex’d prior to epoxy.

I assembled/aligned the epoxied shell sections on the chassis frame/tripod. (Photos)


I had to make a cradle to hold the bonnet of my car this week for transportation to the paint shop.

Among other things I used the hardened carrier/pivot locations for the front. All was made of wood and it occurred to me that given most of us are probably handy with wood, why not just make up spacers/shims in wood to get the bonnet location very close them measure everything and then make or purchase suitable shims in metal?

Sounds like a good idea to me anyway and I will try it once o get the entire car back!

I found the factory shims very easy to work with. having the car raised enough to allow the bonnet to be standing plumb on the hinge pins(bolts) the fore and aft shims that are open ended can be tapped in after loosening the bolts. they can be pulled out by the hole on the end. the vertical shims just drop in as needed . shimming was done without removing the bonnet. I hold the bonnet in place with a stiff leg and an adjustable strap. my car came with extra parts that included shims. I am waiting for some additional new open ended shims for the final fine tuning.

Reviving old thread.

We previously removed the 2 pivot bolts to garner better access for engine work.

This evening we replaced those bolts but now have an alignment issue with the bonnet.

Any advice for correcting this and getting the alignment corrected?

It wasn’t the pivot bolts: what you put in were the spring link bolts. They have little effect on the fit.

Getting a good fit can be a real PITA… best we talk.

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Getting a good fit can be a real PITA… best we talk.

A good psychiatrist is a needed when dealing with traumatic bonnet disorder.

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