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Plastic fender repair question


KDirk
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Ok,

My 88 had the rather common (for 1988 cars) small stress crack near the front of the passenger side front fender. I had my paint and body guy change it out with a spare and repaint, so that much is solved.

Really, my question is this:

Has anyone here repaired a fender with a crack in this location (a few inches rearward of the "tip" of the fender panel, on the top edge) with long-term success? I know that these panels are repairable, per the procedure in the FSM. What I don't know is whether this particular crack, caused by stress from the way the fender was mounted, will stay together if repaired, or will most likely crack through again.

My main reason in asking is that I am trying to decide if I should keep this fender in storage for potential future use, or if I should junk it on the assumption that a repair will not hold up, making it senseless to keep and repair. I hate to chuck a usable part, but if if is probable the crack will recur, then I would like to know that as my storage for Reatta parts is getting a bit tight.

As far as I can tell, this would be a bit cumbersome to repair due to having to get up inside the narrowest part of the fender to apply fiberglass matting and resin to back it up. This may also be a consideration.

Do appreciate any feedback from those who have attempted this repair, and had it last (or not).

KDirk

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my pass one has the same problem. My intention is to put a small piece of wood for support and fiberglass it (since the inner part has a 3/4" section that came out) The glass will seal the hole and the resin will fill the crack then sand it. The wood will hold it tight and when covered with fiberglass it'll stay strong and not rot and fill the gap inside the engine compartment. You can pick up a fiberglass kit from the auto store and theyre easy to use.

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Recian,

Thanks for the input. I guess I'm just concerned over the possibility that it will re-crack at some point after repair. If the crack were due to ordinary damage (impact for example), and in the face of the panel (or the side if you will) rather than being a mounting-stress induced crack in the top/narrowest part, I would have no reservations about repairing it and expecting it to last indefinitely.

Just can't help worrying that if repaired and put back on the car, that the mounting stress that caused it to crack the first time will cause the same problem again, or perhaps cause it to crack elsewhere even if the repair on the original crack holds.

The other issue is that all plastics have expansion/contraction based on heat/cold. While a fiberglass repair on a plastic panel is usually good "forever", since the plastic will expand/contract at a different rate than the resin/glass will, there is that to consider as well.

On a related note, can anyone comment specifically on what changed in regards to the front fender mounting after 1988? Seems the 88's are the only ones to have this issue, and later years were resolved by some means (different mounting, revised torque spec, or some other fix?). I have wondered if there was a TSB on the subject, so that 88's that had the problem under warranty could be modified on repair to prevent re-occurrence.

KDirk

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If you repair it with fiberglass use Kledgecell core mat instead of wood to reinforce it. It is available in different thicknesses and is made to conform to the surfaces. I have a friend who owns Allison Ultra Performance Boats who swears by it. He uses Kledgecell exclusively in his boats. No wood at all. The transom is a steel and Kledgecell laminate. Good stuff that never rots.

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Guest crazytrain2

I would drill a couple of small holes through iy as well(.125" or so) one at each end of the crack to reduce the chance of the crack propogating further.

Depending on the material the fnder is molded out of (likely PolyProprylene, ABS or a glass filled nylon) you may want to drill a few more holes along each side of the crack to give your repair material ( Personally I like the Gelcoat and Fiberglass recommendations) something to flow into thereby forming a mechanical bond. This is especially important if maaterial is PolyPro. because nothing will bond to "Olefin" type plastic's.

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  • 9 years later...

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