Installing Fiberglass Rear Bumper on SC

CabMike · 02-27-2006, 05:05 PM

I just purchased a fiberglass rear bumper for my 1983 Cabriolet. I purchased this second hand so I did not get any instructions with it. How does this mount to the car? I assume you do not use the existing bumper shocks.

Has anyone mounted one of these with a support bar behind it for extra protection? I want the clean look but am concerned about how this will hold up in an accident.

Thanks,
Mike

Spede · 05:16 PM

It's not really going to hold up in an accident. Usually, these are just bolted on where the rear bumper extentions would have been with three bolts on each side.

Assuming that you're going to do something like this:

CabMike · 02-27-2006, 05:21 PM

Steve,

That is the exact look I'm going for! I even have the 964 decklid already mounted. Is that just held on with the three bolts on each side?

Thanks,
Mike

Spede · 02-27-2006, 05:26 PM

Mine is... I'm sure you can add more mounting points but Peter at Rennspeed told me that it should be secure enough. And after six years it has held up just fine.

bkreigsr · 12-03-2020, 06:13 AM

Thread from 2006

Has anyone done this bumper recently?
What three bolts are they referring to?

It looks like my bumper will mount to the two studs glassed into the blade, and the two holes in the top of the bumper shock. (after I removed the shock studs)

Thanks in advance
Bill K

Helix8 · Helix8's Garage

Hello Bill,
I think the bumper you bought on PP Used Parts Classified came with two brackets as well as studs glassed into the bumper? I was looking at that one after I found another recently. I would use the brackets provided and remove the bumper shocks. The bracket mounts to where the bumper shock attaches on the body. I'm fabricating one bracket for one side and will use a Rennline tow hook (bumper shock-like) on the other side. There are three bolts holding the L&R side panels to the body that are removed for the fiberglass bumper (with the accordion bit) maybe this is what is being referred to? I do not think that is near enough though.

bkreigsr · 12-03-2020, 08:14 AM

Thanks.
I was thinking that's what they were talking about. I could not remember if they were sheet metal screws or bolts. They now secure the bumper extension panel, correct?
I fab-ed up another set of bumper shocks from some tube stock and intend to mount the new bumper studs directly to them.
I'm going to wait until I have the rear apart before I decide which way will be easiest.

(You're going to replace your beautiful 'custom' bumper and valance ?)

Bill K

Helix8 · Helix8's Garage

I still have the beautiful custom bumper and valance (you do great work). I get a lot of positive comments on it but I'll be storing them for future use as this car is now 98% track (DE) and looking to lighten up in places. Sounds like you have a good solution for your bumper. Did the brackets come with your bumper? If so, what are your plans for them as I'd be interested. My bracket is made out of aluminum flat stock and not so elegant. All the best, rh

Reiver · 12-03-2020, 10:39 AM

I used the Euro crash tubes...cut and sleeved....you can easily remove the bumper in this manner...did it at home and they came out great...then sent to painter and he removed them to paint and had no problems....front/rear the same

Reiver · 12-03-2020, 10:41 AM

the results

bkreigsr · 12-03-2020, 01:39 PM

Helix8 - I finally actually got down on the ground and took a look.
Yes, I did get the TRE brackets with the bumper. They look like the way to go. They allow for a fore/aft adjustment and side/side adjustment - something I would not be able to do with the blank shocks I made.
I could not picture where the body side hole would go - they line up with the strap clamp bolts that wrap halfway around the shock.
Looks a lot less work than I envisioned.

Reiver - thanks for chiming in. Yours look a lot like what another member (JeremyD) did to his RS clone., front and rear
Did you have any trouble lining up the gaps at the wheel arches ?
Edumacate me on hanging fiberglass bumpers.

Bill K

Reiver · 03:28 PM

No issues at all as the bumpers (both) were well made and a good fit...no cutting or 'fixing' was required. It looks difficult but was easier than I thought but a two man job....good friend helped with the final line up of the bumper side brackets..on...off etc.
No matter what system you use you'll note a tie down strap over a pad across the back of the 911 tail.
That helped immensely when lining everything up...ratcheting it into position gently...great extra set of hands.
I drove the car a bit prior to painting and nothing moved or shifted....just remember you are using Fiberglass and back your thru bolts with large washers of straps to spread the pressure. They have been on a year now.
These are EB Motorsports bumpers.....

What do the TRE brackets look like?

bkreigsr · 12-03-2020, 04:50 PM

Thanks for the additional feedback.
TRE brackets. (I think they are stainless.)
I'm taking them to be powder coated tomorrow.
Bill K

Reiver · 12-03-2020, 05:20 PM

Good luck.. if you run into an issue call out...I may have been here.

bkreigsr · 12-03-2020, 07:17 PM

I like the strap idea.
Did you put license plates lights on your bumper?
Bill K

Reiver · 12-03-2020, 08:32 PM

Quote:

Originally Posted by bkreigsr

I like the strap idea.
Did you put license plates lights on your bumper?
Bill K

Nope....small LED's that double as license plate bolts....similar

https://www.superbrightleds.com/moreinfo/led-wired-bolts/miniature-led-license-plate-bolt-stud-mount-pigtail-connection/1685/