Rear bumper replacement
06-30-2006, 05:06 PM
#1
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Location: Lincolnshire,ENGLAND
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Rear bumper replacement
Hi, need some info from you guys,
I need to replace the rear bumper on my 77, but what do i go for fiberglass ,flex-fit or urethane, do some match up better than others?
any tips for undoing retainers ect.
thanks Mike
I need to replace the rear bumper on my 77, but what do i go for fiberglass ,flex-fit or urethane, do some match up better than others?
any tips for undoing retainers ect.
thanks Mike
07-01-2006, 11:05 AM
#2
Burning Brakes
I put a Flexi fit on my '74 because I wanted the true 2 piece bumper. The fit was nearly perfect and required no body work to the car. the bodyshop sanded, primed, and painted the rear bumper pieces and I took my time lining everything up and adjusting slightly as I tightened the bolts.
I went with the True Flex on my fathers '75 and the fit was really good on his as well. In order to fit the '75, the stock tailight brackets behind the stock bumper, and the alumninum ends pieces of the stock rear bumper support needed to be removed and discarded, and then the main bumper support bolts needed to be loosened and the support brace aligned to get the bumper to fit perfectly.
You will find that if you make oval shaped holes in the replacement cover, things will go much smoother and you will be able to make fitment adjustments. There is a little flex in the bumper cover so I started at the top, middle of the bumper, tightened down the first hold down, then pushed on the cover to get the best fitment for the next section, tightened that down and so on.
As far as removing the old brackets, I used a 1/4 drive and socket on most and in some areas needed to use a small wrench. If you have a ratcheting wrench that would be perfect. If you are lucky, most of the studs will break when you take the old cover off. When you replace the bumper, be sure to purchase the replacement stainless steel T brackets to hold the new cover in place.
Ron
I went with the True Flex on my fathers '75 and the fit was really good on his as well. In order to fit the '75, the stock tailight brackets behind the stock bumper, and the alumninum ends pieces of the stock rear bumper support needed to be removed and discarded, and then the main bumper support bolts needed to be loosened and the support brace aligned to get the bumper to fit perfectly.
You will find that if you make oval shaped holes in the replacement cover, things will go much smoother and you will be able to make fitment adjustments. There is a little flex in the bumper cover so I started at the top, middle of the bumper, tightened down the first hold down, then pushed on the cover to get the best fitment for the next section, tightened that down and so on.
As far as removing the old brackets, I used a 1/4 drive and socket on most and in some areas needed to use a small wrench. If you have a ratcheting wrench that would be perfect. If you are lucky, most of the studs will break when you take the old cover off. When you replace the bumper, be sure to purchase the replacement stainless steel T brackets to hold the new cover in place.
Ron
07-01-2006, 06:44 PM
#4
Drifting
Fiberglass will be the best looking if originality is not important, urethane will eventuall sag and ripple like the original. Unlike most, on fiberglass covers, I prefer to use the tail light brackets on '75 and later cars because they provide extra support for the bumper cover. If you eliminate them you are hanging all the weight of the bumper cover from the rear body flange alone, GM didn't design that body flange to support the weight of a fiberglass cover under normal driving conditions or the side stresses due to lack of lower quarter panel support. The tail light brackets can be modified (pretty simple) so that the fiberglass bumper cover and tail lights can be mounted exactly like the original, PM me and I can give you directions.
I personally like ACI bumpers, I've found their molds are closer to original than Toledo Pro and the parting lines are much cleaner which saves prep time. Toledo Pro bumpers tend to be a little shorter at the bottom, especially the '80-'82 molds which are 1" shorter than original.
As mentioned (if you use one of the 2 types of fiberglass covers) you will need to remove the 2 bumper guard supports and I would also remove the horizontal rubber cushion that is attached to the reinforcement and the center support located on top of the reinforcement. You don't want any parts rubbing on the fiberglass after installation.
If you are having trouble removing the mounting nuts around the perimeter, the studs will break away from the original retainers provided you don't round off the nut. Vise grips or a Dremmel tool with a cut off disc will be helpfull but be carefull, don't go crazy with either and end up cutting or breaking fiberglass. Wear gloves and long sleeves, because you will remove skin from your arms rubbing against the fuel tank shield. You can purchase new stainless retainers or the stock style retainers will fit the ACI bumper cover.
While the bumper is off, it's a good time to replace the rubber fuel lines from the sender to the top of frame if they are old and crusty.
I personally like ACI bumpers, I've found their molds are closer to original than Toledo Pro and the parting lines are much cleaner which saves prep time. Toledo Pro bumpers tend to be a little shorter at the bottom, especially the '80-'82 molds which are 1" shorter than original.
As mentioned (if you use one of the 2 types of fiberglass covers) you will need to remove the 2 bumper guard supports and I would also remove the horizontal rubber cushion that is attached to the reinforcement and the center support located on top of the reinforcement. You don't want any parts rubbing on the fiberglass after installation.
If you are having trouble removing the mounting nuts around the perimeter, the studs will break away from the original retainers provided you don't round off the nut. Vise grips or a Dremmel tool with a cut off disc will be helpfull but be carefull, don't go crazy with either and end up cutting or breaking fiberglass. Wear gloves and long sleeves, because you will remove skin from your arms rubbing against the fuel tank shield. You can purchase new stainless retainers or the stock style retainers will fit the ACI bumper cover.
While the bumper is off, it's a good time to replace the rubber fuel lines from the sender to the top of frame if they are old and crusty.
Last edited by crazywelder; 07-01-2006 at 06:46 PM.
07-01-2006, 06:57 PM
#5
Does it get parked out side? How hot is it where you live? Dark or light colored vette?
I had a Urathane replacement from Ecklers on a black vette in Arizona. Started warping in 2 years. So bad now (many years latter) it looks like the tail is melting.
I had a Urathane replacement from Ecklers on a black vette in Arizona. Started warping in 2 years. So bad now (many years latter) it looks like the tail is melting.