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I feel like an idiot for asking this, but...

My engine/firewall access panel was only being held on with three bolts. I took one of the existing bolts to the hardware store and was told it was a 5-.8 bolt. I watched the guy screw it into the "sizer" thing and everything.

When I try to screw everything back together I have problems. It is hard to screw the bolt into the square nut that is attached to the firewall, but they are the same size as the bolts that where in there before...or are they?

I can get the bolt started, but then the square nut attached to the firewall just spins, so I can try to tighten it all I want, the nut just spins and I never get anywhere.

Do I have the wrong size bolt?

I hope my description makes sense, I am so furious I can barely type. I spent hours cleaning the firewall and access panel and putting Dynomat and Extremeliner on everything, but now I can't finish the job because of a few stupid bolts.

R.
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5mm X 0.8 is correct. I have the same problem from time to time.

First chase the thread with a tap. Clean out all of the tar, and gunk that gets into the threads. That will make a big difference.

Second take a close look at how the square nuts are held captive in the body. You might have to hammer the metal that holds the nut to retain them better. Hard to explain, but here is a flap of metal on the outside frame that retains the nut into its hat. If that flap bends or deforms it allows the nut to spin or worst case fall out.

I had to fab up a few missing nuts on my project that fell out.
...I have a Metal screw checker right here. The screws are 5mm But Do NOT screw into the .8 (Not unless I use a wrench and Force them through!) Nor do they fit the .5 Pitch Threads. And It's not a damaged screw as I tried Four of them. These screws are off a '74...
I got the bolts for my bulkhead from the local Yamaha motorcycle dealer.

I don't remember the size, but 5mm seems about right.

There weren't an unusual pitch. Just the everday off the shelf bolts used for holding bits of motorcycle together.

Jap bikes use fine pitch metric, but I don't thinks this makes a difference until you get up to 10 or 12mm diameter.
You can do it without removing the seats. (This is the only way I have ever done it).
But you will have more room to work if you take the seats out.

Move the seats forward all the way (if they will move!). Then remove the seat belt bolts, seat belts and all the little screws that hold the trim panel in. You can then slide the trim panel our a door.

Behind the trim panel you will find the access hatch, held in with a few 5mm bolts.

Here's a tip - make sure that you have enough space to the side of the car to withdraw the trim manual. I got mine stuck between the car and the garage wall! Big Grin
quote:
Originally posted by ackpht:
You want a dumb question? I've owned #3989 for two months. No idea how to access the front of the engine. Do you take the seats out to remove this panel, or just move them forward?

I'd go out to the car and check right now but it's at a tuner's up in SF.

Dan


There are pictures about ½ down this page that show how to do it http://www.panteraplace.com/page123.htm

Mike
quote:
Move the seats forward all the way (if they will move!). Then remove the seat belt bolts, seat belts and all the little screws that hold the trim panel in. You can then slide the trim panel our a door.

Not quite...

There should be about four phillips head screws near the bottom corners of the trim panel that need to be removed. THEN, slide that panel UP, it is supported at the top by two flat metal hooks that drop down into corresponding tabs.

It should n ow be free to maneuver out of the cabin.

Larry
I have made mine even simpler, since I don't have the stock seatbelts with the retractors on the firewall, the only thing that holds it in place are the 2 top seatbelt bolts, I unbolt them and the panel slides right out. I haven't had any problems with squeaks, rattles or anything else. With the folding corvette seats and the "quick release" of the firewall cover I can get in the engine compartment in minutes. I have also had the metal cover held in place with only one bolt (top center) for several years with no problems. I have the metal cover sealed with foam tape weatherstrip to keep it sealed for noise and rattles and fumes.

just my 2 cents

Gary #06984
quote:
Originally posted by Pantera 1887:
quote:
Originally posted by ackpht:
You want a dumb question? I've owned #3989 for two months. No idea how to access the front of the engine. Do you take the seats out to remove this panel, or just move them forward?

I'd go out to the car and check right now but it's at a tuner's up in SF.

Dan


There are pictures about ½ down this page that show how to do it http://www.panteraplace.com/page123.htm

Mike


Thanks. Word from the tuner is that after a new carb, water pump, plug wires, and a dance on the dyno, #3989 is much improved. If anyone sees a red pre-L leaving SF southbound on 101 on Friday 11/30, it's probably me!

Edit: no problems, car runs much better. Tuner says the next thing to do to add power is put on Edelbrock heads (hmmmm). Drove alongside an Audi R8 on the way back- didn't know those were on the street yet!

Dan
Last edited by ackpht
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