Body work on rear valence - two types

[Mikes Z car]

Hi all,

My 240Z was rear ended before I got it though the only damage I can see is the drivers side bumper mount point was pushed forward 1/2 inch and there is a 5 inch diameter "soft" dent just under the bumper that can be seen in the right side of the picture where the paint has come off. I have done some body work before but I am not very experienced. I assume the soft dent could be pulled out with a slide hammer or whatever they call them but is there another option? The bumper mount point has a reinforcement plate on the inner side of the valence which should make it more difficult to pull out using a slide hammer I would assume. I thought of using a come along and a strong tree but I doubt anyone experienced would do that. I want to get the mount point moved back closer to the bumper (the normal position) so I can get the 1/2 inch bondo thickness reduced or eliminated to where it won't crack. Also the bumper mount point is missing one of the two welded on nuts. The previous body work person just had the nut loose on the inner side of the valence and the bumper mount butted up against the 1/2 inch bondo layer on the outside. I have read how to weld a nut on the outside of sheet metal using a washer welded to a nut which I assume I will have to do since welding another nut on the inner side would be in extremely cramped quarters. Anyone have ideas or experience with these kinds of repair? My questions are how do I move the bumper mount back to reduce or eliminate the thickness of the bondo for the bumper mount point, how do I install a welded on nut for it and how do I fix the soft dent with limited access to the backside of it. Any information appreciated!

The blue area in the picture just shows the area of the bondoed mount point, the bumper and the mount attached to it are okay (I have a new bumper).

Mike

[cygnusx1]

When my 280Z was lightly rear ended (wearing 240Z bumpers), the restoration shop cut off the valence, straightened all the metal behind the valence, painted and undercoated the areas, reformed the dented valence, and welded it back into place.

Edited October 14, 2011 by cygnusx1

[madkaw]

That will be a tough fix. Try and keep the stock valence since aftermarket sucks. The best fix is as mentioned above- drill out spot welds and remove valence , then repair. Or you might remove gas tank and beat it back from the backside. Sorry, but no easy fix there.

[palosfv3]

Better pictures of the exterior with the bumper removed , the inner floor near the lt tail lamp and the underside of the lt rail end are needed before any determination of what is the best way to repair is made.

[Mikes Z car]

Thanks for the idea of removing the valence and the gas tank removal idea, I hadn't thought of those ideas!. I was thinking of dropping the tank eventually. Attached are better pictures thanks for asking for them, they were needed I see now.

I remember when I had my 71 240Z the rear valence was pushed closer to the car on the left hand side where the muffler was. This was straight across the car. There was no sign of damage but I suppose it could have been well hidden. Is the rear valence at the very bottom edge supposed to be straight across the car or is it supposed to graduate closer to the front of the car as it gets closer to the muffler?

Mike

[5thhorsemann]

It doesn't look too bad, but it really sucks when these "little" spoiler accidents happen. Lots of work to fix little damage. Sorry to hear 'bout your luck.

[palosfv3]

Its still difficult to tell with all the bondo in the pics as the real condition of the metal is covered.

Once you remove the bondo you should have a good idea of what your dealing with . From whats in the pics the lt mount bracket for the rear bumper appears to be driven into the floor pan and rail end. Having pulling equipment will make things easier to do especially if there is a kink at the end of the rail . If you can it would be best to attach a plate to the bumper bracket mounting holes to pull on . Watch the seam of the floor pan to the inner rear body below the lamp as you pull so the spot welded flange doesnt start to spread open .The Z has the design misfortune of the rear most body crossmember being welded to the outer rear body panel and the rear body panel being the bumper bracket support. This makes repairing things difficult . The recommendation of cutting out the rear valance has relevance but try to keep the cutting to a minimum .

[Mikes Z car]

Larry,

Thanks for the information I appreciate your taking the time to share the details. I start taking off bondo today to see what is really there. I will post more pictures with the bondo off if it looks like it might be a good idea to put another set of eyes on this. Hopefully the mounting point bracket is all that got pushed forward, it looks like that might be the case since I can't see any obvious damage to the frame rail end though damage could still be hidden.

Thanks for everyones ideas.

Mike

[Mikes Z car]

Pictures with metal plate from previous work removed and most of the bondo removed. Tank will have to come out I think.

[palosfv3]

Best bet is another lower valance/body panel . You have quite a bit of damage there and it appears to be across the entire panel as well as the ends of the quarters. Not a bad idea to get the tank and muffler out of the way.

[grantf]

Strange someone whent to the trouble of welding in that peice of metal at all. Looks like you need to find a clean rear end from a parts car and replace the whole thing.

[Mikes Z car]

The car had two tailpipes side by side merged into one at the rear of the muffler when I got it with the original corners of the valence at the muffler's rear end bent back out of view and the welded on plate around the tailpipe hole I think was used to redefine the hole as squared off for the two tailpipes to go through. There are many holes in the valence around the tailpipe where the previous bodywork person used a slide hammer to pull out the valence. It didn't get pulled far enough out and that is why the bondo was 1/2" thick where the bumper mount bolt holes are.

I took a 4 lb sledge to the back of the bumper mount point with a wooden drift where the two bolt holes for the bumper mount are to see if I could push it towards the rear of the car so the bolt hole surfaces are more flush with the valence surface like the other bumper mount. My reasoning is that if I can do this then the bondo needed then will be 1/4" max on the sheetmetal which I don't think will crack will it? The bondo that was on there had a crack in it I think because it was too thick. Anyone know how thick you can make bondo without it cracking? It may depend on what part of the car you put it as far as flexing?

Replacing the valence is a little intimidating but may be possible even with my limited welding skills. Does the valence end under the license plate or does it go to the bottom edge of the hatch sill? What kind of grinder do you grind off the welds with, an angle grinder? I have read some drill them out.

Thanks everyone for the great information.

Mike