71 Nose surround reinforcement bar

[Andy Higbee]

While inspecting the engine bay noticed the steel nose surround bar is badly rusted on the outside. Not sure what the inside looks like but has me worried. Am wondering if there is any way to drill out the rivets and drop this bar for repair and paint. In looking at the AIM it appears this steel piece is bonded and riveted to a bonding strip and the bonding strip is then bonded to the nose. I also have the classic rivet head indications popping up on the front of the nose section.

Can I drill out the rivets and drop the bar?
Remove the glass above the rivets?
Bond and rivet the repaired/painted steel bar?
And finally re-glass/repair the holes created by removal of the rivets?

The areas above the rivets needs to be reaired regardless so thought this might be any easier method of repair versus trying to delaminate the bonding strip with metal reinforcement from the nose of the car.

Any help would be appreciated!!

AndyH

[Joe L.]

Re: 71 Nose surround reinforcement bar

Andy-----

Yes, you can and DEFINITELY SHOULD do the repair exactly as you have surmised and described. You will find that the aluminum rivets which retain the reinforcement to the upper surround panel will have likely completely deteriorated. The reinforcement, itself, may or may not be beyond restoration. This piece, GM #3938095, is GM-discontinued. However, Dr. Rebuild shows some NOS stock in his catalog. Also, this part may be available in reproduction.

Many years ago there was an OUTSTANDING article in Vette Magazine written by Ralph Eckler regarding the complete repair procedure for this rather common 68-72 malady. Unfortunately, I don't recall the issue date.

[Andy Higbee]

Re: 71 Nose surround reinforcement bar

Joe,

Thanks again for your advice. Being a Corvette owner for the past 20 years I can't believe I waited so long to join the NCRS. Of course seperating body and engine from frame probably forced the issue!!

Thanks Again!
AndyH

[Harmon C.]

Re: 71 Nose surround reinforcement bar

With todays bonding adhesives you may not need the rivits as 1973 and newer were bonded only. I don't know if a 71 would need the rivts for support.

[Jack H.]

Welcome to NCRS!

Now, to make your long belated membership application give you a return on your money, how about we take you by the hand and tell you the 'secrets' of how to do the job right?

Reason for the malady is system uses steel bar, aluminum rivets and a 'sandwich' of fiberglass. What you've got is potentially a galvanic cell (battery)--dissimilar metals with dielectric barrier. All that's needed to complete the galvanic cell is an electrolyte.... Now, where on earth would we find same????

How about throwing salt water up into the nose? Hey, BINGO, the job is done! Once the original, thin, dichromate protective paint on the steel bar is breached and the car is driven over winter roadways, the 'battery' is complete. As a result, the chemical reduction/oxidation reaction produces a 'salt' (in the chemistry term) which is aluminum oxide and it migrates up/over the aluminum rivet heads causting the 'bulges' you see.

There are two solutions: (1) elaborate (remove and replace all worn components), and (2) quick & dirty.

The second solution goes like this:

(1) Drill out all the rivets from top down except for a strategic few to hold
things in place.

(2) Fill the resulting holes with fiberglass (NOT just bond--the bond will shrink and the repair will re-surface after a few months, a few years).

(3) If you want concours undetectable repair, look at the bottom side of the rivets BEFORE you drill them out. Either save the original ends or cut the ends off fresh new rivets. Now, remove all the nose items (wiring, Etc.), clean the underside of the reinforcement bar, repaint with fresh dichromate paint and 'stick' your 'dummy' rivet ends into the inserted fiberglass fill
while she's drying/setting up.

(4) Repeat the process on the remaining 'strategic' rivets. Sand the upper nose surface and repaint. You're done!