Sebring style fiberglass front fender   Sebring style fiberglass quarter panel

How To Install Fiberglass Fender Flares

(specifically: how to install the MG Owners' Club "Sebring" flares)

The British V8 Newsletter, Volume XV Issue 3, December 2007

by: Simon Austin

This article provides detailed description of the work involved to install ready-made fiberglass fenders on a sports car. The installation steps and techniques shown in this article apply to other styles of fiberglass fenders and flares, to products from other vendors, and even to installation of flares on other car models.

I purchased my "Sebring style" fender flare kit from the MG Owners' Club ("MGOC") in the UK. For just over $1200 (Canadian) including shipping, the kit included two complete front fenders and two rear quarter-panels from the top of the fender down. The Sebring kit is offered in roadster or GT versions, and obviously I chose the roadster version, but the installation process is similar. (The fenders differ near the windshield "A-pillar".)

The styling of these particular flares was clearly inspired by the fenders on the two famous MGC GTs that successfully raced in the 1968 "12 Hours of Sebring" race. These original MGC race cars were actually built with riveted-on aluminum fender flares fabricated by a "panel beater" at MG's Abingdon works (not by Pressed Steel, the company that provided MG with stamped steel body panels.) The MGB GT that MG raced in a smaller-engine class at Sebring in 1968 wasn't fitted with flared fenders.

test fitting the MGOC fiberglass quarter panel

Let's start with the rear quarter-panels, as their installation is somewhat easier than the front fenders. Each quarter-panel was laid up against the car for sizing and to get an idea how much fiberglass would need to be removed.

removing the old quarter panel with a plasma cutter
Warning: always wear eye protection when operating a plasma cutter!

Since my car's body was in such good condition and since I was planning to use its original doors, my body man and I decided to leave the steel quarters intact where they met the door, the top of the fender and near the taillight. This would ensure that gaps stayed true and the fender strip at the top was undisturbed. A plasma cutter was used to remove the steel quarter panel about an inch in from the edges.

MGB rear fender modifications   fiberglass quarter panel

From this "template", the fiberglass quarter panel was laid against the steel quarter. From inside the car, we just drew a line on the fiberglass panel for future cutting.

quarter panel removed, but a flange was left behind   butting panels together against a backing strip

The intent of mounting the fiberglass panel to the steel panel was never to overlap one over the other but to "butt" the two together. A metal strip would be attached to the backside of the two surfaces and this became the "overlap". Attaching the strip to the steel quarter was simple enough with welding. Two-part industrial adhesive was used to attach the fiberglass panel.

Sebring flares on quarter panels   Sebring quarter panels

smoothing out imperfections with body filler   fiberglass removed and rebuilt with new cloth and resin

With the rear panel "glued" in place, work began to smooth out the imperfections or scuffs in the fiberglass panels. The area in front of the rear wheels was a particularly bad area for getting the fiberglass smooth and some had to be removed and then rebuilt with new cloth and resin for a finished look.

large gap inside the inner wheel arch

That pretty much takes care of getting the rear quarters to a "primer stage".

There was only one area that needed a little bit of further modification: because of the addition of about 3" of flared fender, there was a large gap inside the inner wheel arch. Here we added strips of metal, bonded to the fiberglass panel and welded to the metal arch. With a test drive, I discovered that the rear wheels rubbed (rather loudly!) on the metal inside the arch. I took the car back to my body-man and he removed a section of metal about 8" long inside the arch and replaced it with fiberglass, suitably rounded off to accommodate the tire. With about 5000 miles on the car since this modification, no rubbing issues have been detected.

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Now let's talk about the front fenders. These presented a much more challenging project, in that they are not the finest moulded fiberglass fenders made. Sure they look like MGB fenders in these photos - but looks are deceiving! Once the steel fenders were removed (and sold, because I thought I wouldn't need them anymore), the fiberglass ones were placed on the car.

trial fitting the hood / bonnet   Special Tuning ST spoiler

chrome bumper conversion

As can be seen in the pictures, I've added the ST spoiler so this had to be blended in with the fenders. Also, my car started out as a "rubber bumper" (post 1974) model, but I planned a "chrome bumper" conversion - so those changes need to come together too.

The most difficult area to fit properly on these fenders was at the rear top where the fender meets the windshield frame. When you order this kit, you specify whether you want the GT or roadster. After much cutting and rebuilding in the windshield-to-fender area, I don't think it would really matter if you got the wrong fenders for your project. The problem here is poor fit quality. The curve of the fender had to be cut out, fiberglass added in to reshape and then the curve added back in to follow the car. The overall fit of the fender is good in that it sits in the correct position, but it does take a lot of reshaping in small areas to make it look like it came with the car. The turn signal light area is shaped and easy enough to cut out for your lights. Remember to add a ground wire from the light housing to a good ground on the car as the original housing just grounded itself by being attached to the steel fender. The headlight housing is mounted the same way. Cut out the fiberglass, mark your mounting holes for the bucket and all the associated light fittings and you're set.

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inner brace for mounting fiberglass Sebring fenders

As many MG owners will already know, the rear of the original steel fenders mount to the car by use of a steel vertical panels that are welded to the fender and then bolted to the car. The fiberglass fenders have their own versions of these panels, but they're totally useless. They're not in the correct position, so I removed them. In the picture above, you can see how an inner brace was made to replicate this panel. This bracket was bonded to the fiberglass fender. Then I used the original holes on the car to mount the fender.

This area is hidden behind the stock MGB splash panel that installs in the factory location with the only addition being some metal added at the bottom to fill the gap created by the flare. The outer edge of the splash panel has a rubber weather-strip and it seals against the fiberglass fender nicely.

adding small verticle panels on either side of the grille

Inside the engine compartment, holes are drilled through the fiberglass fender to install the bolts to hold it to the car. Mounting the fenders at the front involved adding small panels to replace the vertical ones on either side of the grille that were attached to the steel fenders.

You can just see the original panel mounts for the fenders. The easiest way to attach the fiberglass fenders is to source some old steel fenders, cut off the small panel that attaches the fender to the car and attach these to the fiberglass ones. Then sculpt the fiberglass around the grille opening to the proper shape. Having a grille to use makes this step much easier.

checking fit with the grille and bumper

reinforcing the lip of the wheel arch

The last step before the final bodywork, primer and paint is to reinforce the wheel arch lip of the fenders. As shown above (here and also three photos up where the inner brace was shown) the arch lip is literally a sharp edge. Some may elect to leave it like this, but adding strength here will prevent someone from leaning on the fender and cracking it. My body-man came up with some foam strips that he attached to the lip, built it up with resin and then fibre-glassed under the arch to give the lip a "horizontal" edge. To give further strength to the fender (and to prevent rocks and debris off the tires damaging the underside of each fender), we chose to apply spray-on truck bed-liner material under each fender. This product was used on the rear fenders as well. Now that the car is done, it's hard to tell that the fenders are actually fiberglass.

Looking back on this project, the only thing I'd do differently is to not use the complete fiberglass front fenders. Installing the fiberglass front fenders certainly isn't as simple as just bolting them on (as you may have gathered.) If you have or can procure a reasonably staight set of steel fenders, I'd recommend bonding the flared sections of the fiberglass fenders to them (much like the fiberglass rear quarters are attached.) Installing complete fiberglass fenders seems appropriate for repairing a car with extensive collision or rust damage, but if available I think it'd save considerable work and avoid hassles to use steel fenders as a foundation.

inside the paint booth

removing the masking

front fenders reinstalled for the trip home

the color of these Minilite wheels is called Anthracite
Genuine Minilite wheels (Made in Britain!) complete the authentic vintage-performance "look".

Genuine Minilite wheels - still custom made in England

For more information and photos, please see Simon Austin's "How It Was Done" article.

Disclaimer: This page was researched and written by Simon Austin. Views expressed are those of the author, and are provided without warrantee or guarantee. Apply at your own risk.

Photos by Simon Austin for the British V8 Newsletter. All rights reserved.

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