rear bumper clearance

[IdahoBen]

Installed the rear bumper and have excessive side clearance.  Over an inch from the fiberglass to the mounting pad on the bumper.  I think I need to bend the bumper.   What is the standard gap?  As it is the bolts do reach.

[mfg]

There’s a 1/4” rubber shim that fits in between the bumper and the fiberglass body which will fill some of that gap.

The gap on your Avanti does look excessive.

I’d add a second rubber shim, then tighten the bolt to crank it in.

[regnalbob]

The width of the bumper between inside edges is approximately 63 inches.

The gap at the front edge is 1/2 inch.

The gap at the shim is 5/8 inch.

Edited Thursday at 08:36 PM by regnalbob

[IdahoBen]

dont think I like the idea of cranking on bolts to put that kind of constant strain on the body.   I will try to bend the bumper tomorrow.  Thanks regnalbob for the pictures and the measurements.

[mfg]

51 minutes ago, IdahoBen said:

dont think I like the idea of cranking on bolts to put that kind of constant strain on the body.   I will try to bend the bumper tomorrow.  Thanks regnalbob for the pictures and the measurements.

I’d go easy when doing this .. but it’s the bracket itself taking the strain...
You don’t want the bumper too close to body, as shown in photo, as a possible side impact will mean certain fiberglass damage…..

Also, those bumper sides come in fairly easy when tightening the side bolts… just go slowly… Trying to straighten the bumper off the car can be done, however that’s unfortunately a good way to crack the chrome plate.

Edited 23 hours ago by mfg
Added text

[regnalbob]

14 hours ago, mfg said:

You don’t want the bumper too close to body, as shown in photo, as a possible side impact will mean certain fiberglass damage…..

 

 The bumper is exactly the way it was installed at the factory with a 1/4 inch shim on each side.

The gap is the same on both sides.

 

[ronmanfredi]

6 hours ago, regnalbob said:

 The bumper is exactly the way it was installed at the factory with a 1/4 inch shim on each side.

The gap is the same on both sides.

 

Regnalbob's image is correct and looks just like my R2 rear bumper.  IdahoBens bumper is obviously bent outward on each end.

[mfg]

2 hours ago, ronmanfredi said:

Regnalbob's image is correct and looks just like my R2 rear bumper.  IdahoBens bumper is obviously bent outward on each end.

Obviously!

My point here is to be careful if attempting to straighten an Avanti (steel) bumper off the car, as it’s quite easy to damage (crack) the chrome plate….

Also, if the Avanti in question is going to be driven more than occasionally, as I do mine, I believe that a bit of extra clearance over factory spec between the bumper and the fiberglass body is a prudent move.

After repairing more Corvette and Avanti fiberglass bodies over the years than I care to remember, that’s my take on this.