Bumpers -- shortening the projection of the rear bumper?

[SteveJ]

These are the 5 mph damage control bumpers, with shock absorbers inside the mounting struts. I have seen somewhere, that you can either compress the shock, drill some holes and lock it in place (creating a big surprise for a future owner) or I think that you can carefully take them apart and remove the springs before locking them in place.

That's what I recalled reading, but since I was too lazy to search for the description, I didn't try to give specifics.

[g9m3c]

I did that to my '74.

Before (black plastic pieces removed)

Shocks compressed and welded

After

Once you take the bumper off of the shocks, you will see a small screw in the middle of the mounting flange on the shocks. Remove this screw and the pressure will be released from the shock. Compress it to your desired length, and weld/drill/bolt it to secure it there.

Hope this helps.

Edited November 19, 2010 by g9m3c

[lonetreesteve]

No offense, but I personally don't like the look of the big bumpers. As everyone knows, they were added due to U.S. federal regulations and they completely changed the look of the original S30 design. However, I know that you like the late '70s look and I think that the look of the early 260Z bumpers isn't a bad one, so it would be a good compromise between the 240 and the late 260/280 bumpers.

[grantf]

If you move the bumper inwards could you then cut out two or three "ribs" from the bumper ends and glue them back together using bumper compound?

I have repaired the ends on mine using it and reinforcement mesh and they seem to be holding up well, you cannot even see they were damaged.

[FastWoman]

G9m3c, thanks! That looks like the trick.

And grantf, do you mean this stuff?

http://www.seenontvproducts.net/bumper-repair-kit/index.html

[texas280]

I found these pictures on the internet and saved them as inspiration for doing the same on my 1977 Z

[FastWoman]

Thanks, Texas! Yeah! That looks sharp!

The rear bumper guard has a different shape (other than having a couple of ribs removed) than the stock '77/'78. Specifically, it doesn't project out in a dorky mound. Rather, it just covers over the end of the bumper. I'm wondering whether this was some sort of custom-molded bumper guard. For reference, here is the stock look -- same as mine:

http://www.triadzclub.com/z/classifieds/Mar%2013_08/1977Datsun280Z/index.html

Having thought about this a bit more, I'm wondering whether I could compress the shock to the length I want, drill a hole through it someplace that won't compromise the mechanics of the shock, and put a small diameter bolt through the whole thing to keep the shock compressed. In the event of a collision, the bolt could shear, and the shock might still provide some shock-absorption protection. If desired, the bolt could be removed to restore the bumper position to its stock configuration (also replacing the original bumper guard).

I'm thinking I'll be able to mold my own custom bumper guards, but I'd love to find the pictured ones ready made. Do you know if they exist somewhere?

Edited December 6, 2010 by FastWoman

[ajmcforester]

On your bolt idea would it be easier to just wire it into place, then no hole drilling into the shock and the shock would be allowed to compress. In off road racing they will use a retention strap to keep the shock from fully extending and smacking the valves damaging or breaking the shock. On one end loop it around the mounting point then under the car from the hole for the shock and to that mounting point. You might need to use cable so to keep it tight refer to garage door cables to make the tension part.

[FastWoman]

I like that idea, ajm. In fact I wonder if a turn-buckle could be incorporated to adjust the shock compression. Hmmmm....

On a previous topic, a thought about the bumper guard: Maybe the humps on the pictured rear guards were cut off, sanded smooth, and polished?

[ajmcforester]

The thing I like is you can adjust it later if you want.

On the bumper guard in the last picture it looks like they cut them on the seam and glued it back together taking a couple ribs out

[TomoHawk]

How would you glue that?

BTW- can you get those little round plugs?

[FastWoman]

Tomo, see post #16. I've never used the stuff personally, but this sounds like a promising approach. I'd personally rather try to create a new part than to hack up an old part.

Which little round plugs?