Jeep Wrangler TJ Hard Top Repairs

[jgaz]

Thanks for this @jscherb and @jgaz. I will be prepping mine to repaint it, but I have a couple of tweaks that I want to do to the structure beforehand. I've done quite a bit of fiberglass work in the past, and knew that something looked different about the hardtop's build. My plan was to just use standard polyester resin, so I'm glad to see this info.

I have a somewhat related question. With the top being double-wall, I've wondered about drilling an access point and pouring dense, expanding foam into the hole. In my mind, this may serve as some insulating, but most importantly as a sound dampener. Do you or anyone else know of this being done, and have some Pros and Cons info before I commit to it? As you know, once that's done, there's no turning back.

Glad you found it useful.

Also glad to see @jscherb on here.
If anyone can help any of you with your hardtop questions, he can.

 

[ebdnr]

Looks like there are some serious experts here I just have a question, my top is not that broken, but very pinstriped with some white nicks what shall I use to make it look better? (I’d like to take care of the pinstripes as well) thank you !

 

[Chris]

Looks like there are some serious experts here I just have a question, my top is not that broken, but very pinstriped with some white nicks what shall I use to make it look better? (I’d like to take care of the pinstripes as well) thank you ! View attachment 184572

All that needs is touch-up paint.

 

[ebdnr]

Thank you for the quick reply. The issue with touch up paint is the pinstripes are too many to go one by one with a pencil like paint. Is there a spray that I can use ?

 

[DustyRhodes03]

Thank you for the quick reply. The issue with touch up paint is the pinstripes are too many to go one by one with a pencil like paint. Is there a spray that I can use ?

For sure. You're in Canada it looks like, your closest Canadian Tire will have a whole section of automotive touch up paints that come in spray cans. Napa is another option as well.

 

[OFFRD TJ]

Hello folks - Hope you all are doing well.

While wheeling I damaged my Jeep hard at the rear lower section (see pics) when I accidentally backed into a tree. There was also damage to rear quarter panel but I am not so worried about it as I have armor guards from Motobilt which I will be installing soon. MY biggest concern is the hard top which has some structure damage and I see the mat is very flaky and starting to come loose.

Any ideas about how I can repair the damage? Should I use SMC resin as supposed to fiberglass? And how soon do I need to get this fixed?

As always, thank you for your expert advise.

 

[Terry Tiemeyer]

The following is information posted by user "jscherb" and can be found at this thread: http://forum.expeditionportal.com/threads/189471-Tj-hardtop-repait



I've used urethane adhesives quite a bit but in my experience they're not as good as fiberglass for a repair like the ones you've got to do to repair a Jeep Wrangler TJ hard top. They do bond well to fiberglass/SMC, but two things are lacking:

- A repair using SMC-compatible polyester resin and fiberglass cloth or mat will be stronger than a urethane adhesive repair because the repair will be reinforced with new fiberglass. A urethane adhesive repair will only rely on the bonding strength of the adhesive but a fiberglass repair will rely on both the strength of the bond of the polyester resin plus the reinforcement of the embedded fiberglass cloth or mat. It is possible to reinforce urethane adhesive joints with a doubler plate bonded behind the repair, but even so fiberglass makes a better repair in my experience.

- Urethane adhesives don't sand or finish well, so you can't easily make a repair that won't be visible on the exterior of the hardtop. They're really a "glue" where a fiberglass repair is the same material as the hardtop and is workable in the same way.

Because Jeep hardtops are made from the SMC variant of fiberglass, you'll need to use an SMC-compatible polyester resin, at least for the layer that bonds to the top. It turns out that once the first layer of SMC-compatible resin has been applied to the repair area (ideally with fiberglass matt embedded in that first layer), subsequent layers can be done in less expensive/more easily worked ordinary polyester resin.

Ideally what you'll want to do it gain access to the inside of the repair area and do the main repair/reinforcement on the inside. I haven't worked on a TJ hardtop for a while, but I believe the area you need to repair is double-walled, so you'll need to cut an access hole in the inside wall so you can get to the inside surface of the outer wall. If you cut the access hole carefully you can bond the cut piece back in place after the main repair is done and use some body filler to hide the fact that you ever cut the access hole. Because you say "the piece is almost off" this suggests that the repair needs to be very strong so doing a repair just from the outside surface of the hardtop probably won't be strong enough to last long term.

I recently did a repair in a JK Freedom Panel which should illustrate the basic techniques to use on your repair. Here's the Freedom Panel damage:

View attachment 29949

The fiberglass is cracked to the point where it's no longer structurally sound and some of the outside skin is actually broken off and missing. The panel is double-walled, so access needs to be gained to the inside to properly make the repair. It turns out that in this case the inner wall was also cracked and broken so with a little more cutting I was able to separate the inner and outer shells for access to the inside of the outer shell.

View attachment 29950

In this next photo I've applied several layers of fiberglass mat soaked in SMC-compatible resin to the inside of the repair area. I've used masking tape on the outside to contain the resin and act as a form for replacing the parts of the skin that were broken away and lost in the accident.

View attachment 29951

In this case, since the repair area was small and mostly non-structural, three layers of fiberglass mat soaked in SMC-compatible resin was enough to make the repair, and after those were applied I closed the inner skin and bonded that back to the outer skin with more SMC-compatible resin. The process on your repair would be a little different, since your repair is definitely structural I'd add a few more layers of resin + mat extending out several inches from the crack.

View attachment 29952

Once that's cured, the cracks in the outer skin are mostly cosmetic; the structural repair was done on the inside, so the exterior can be cosmetically repaired with body filler, ideally an SMC-compatible filler. Best practice is to grind/sand the crack so that all of the loose fiberglass is removed and a "valley" if made in the surface to put the filler in. Here's the valley sanded along the crack area:

View attachment 29953

I then applied narrow strips of fiberglass mat soaked in SMC-compatible resin to the crack area:

View attachment 29954

Having done that, I used body filler to fill any remaining imperfections, sanded it smooth and painted it with primer followed by MOPAR hardtop touch-up paint.

View attachment 29955

View attachment 29956

Almost nothing is "too broken" to be repaired using similar techniques; a while back when I was just starting my conversion of a factory JK hardtop to modular I picked up a broken side panel from a hardtop. It was missing a lot of the top edge of the panel but other than that it if repaired would make a good modular side for my project. It also had a large crack along the bottom edge. This repair was a little more advanced than the one above; for the Freedom Panel I was able to use masking tape as a form to make the repair of the missing fiberglass, in this case a lot of area was missing so I used a wooden form as a "mold" for the area to be replaced. The bond for the new area, and the repair of the crack at the bottom of the panel, were done using the same materials and techniques as the Freedom Panel repair though. Some before and after photos...

View attachment 29957

View attachment 29958

Anyway... the damage to your TJ hardtop is definitely repairable, and a permanent structural repair can be done using the techniques described above, particularly:

- Gaining access to the inside of the repair area so the structural repair can be made from the inside. If you cut an access hole in the inside skin carefully enough it can be replaced after the main repair is done and with a little body filler and paint made almost undetectable.

- Using SMC-compatible polyester resin along with fiberglass mat, applied to the inside of the repair area in several layers ending several inches beyond the crack

- Creating a valley along the crack, doing a first layer repair with SMC-compatible resin and strips of fiberglass mat followed by body filler, sanding and paint.

I've used these two SMC-compatible polyester resins with good results:

All Resin: http://uschem.com/index.cfm?page=productDetail&id=143

Evercoat SMC Resin: http://www.evercoat.com/product-deta...art/100864/us/

An alternative to SMC-compatible polyester resin is to use epoxy resin. A good choice in epoxy is West System G/Flex: https://www.westsystem.com/specialty...ughened-epoxy/. Epoxies like G/Flex will actually bond slightly better to SMC fiberglass than SMC-compatible polyester resin, although both types of resin work well. Epoxies generally don't sand as well as polyesters but since most of your repair will be inside that's not an issue.

Evercoat makes several fillers that are compatible with SMC, here's a list of all of their fillers, the ones that are SMC compatible are say so in the description text: http://www.evercoat.com/reinforced-fillers/us/ and http://www.evercoat.com/premium-fillers/us/

You can use ordinary body filler on top of a repair made with SMC-compatible resin though, check the photo I posted of the exterior repair of the crack in the Freedom Panel: I put a base of SMC-compatible resin with fiberglass mat into the crack, and the filler I used on that repair was ordinary filler, I happened to have Shark Bite on hand because I use it a lot in fiberglass mold making so I used that. You can think of SMC-compatible resin as a "primer" for ordinary filler, as long as there's a layer of SMC-compatible on the surface, ordinary filler will stick fine to that. You can apply SMC-compatible resin with a brush as a primer for the filler.

Thanks for this I have a top that needs attention.

 

[jwtj02]

How would I go about fixing the corners? The inside looks to be fine.

View attachment 130407

View attachment 130408

This looks exactly like the problem I now have... did you ever try to fix it?

 

[jscherb]

How would I go about fixing the corners? The inside looks to be fine.

View attachment 130407

View attachment 130408

This looks exactly like the problem I now have... did you ever try to fix it?

I posted this pair of photos earlier in this thread, the method that I used for that repair is the same method you would use to repair the rear corners of the hardtop.

What needs to be done is to build a form on the outside of the panel. I didn't take a lot of photos while I was doing that repair, but hopefully this photo will explain it well enough.

Looking back at the photos above, there's a missing portion at the top of the panel, and a large chunk and crack at the bottom middle of the panel. In this next photo you can't really see the form I made for the top of the panel, but it's two pieces of wood attached to the panel, they're joined at a 90-degree angle to form both the outside surface of the panel and the flange at the top of the panel, which faces 90 degrees inboard. The form for replacing the chunk at the bottom is a simple piece of wood clamped to the outside of the panel. Both forms are covered with masking tape where the fiberglass repair will be done, and the masking tape has several coats of mold release wax applied so the repair won't stick to the form.

I'm sorry I don't have a better photo of the forms, but maybe the following text and illustration will help.

To repair the rear corners of a hardtop, first remove the hardtop and it'll be easier to work on if it's upside down. For this repair I would make a form out of flexible plastic you might find at a craft store. I would cut a piece of plastic larger than the repair area and I would secure it to the hardtop with screws because it may be difficult to clamp it in place on the curve. The screw holes can easily be filled in later. In this next illustration I've made the form a bit transparent so you can see where it might go and where the screws might go.

Once you've got the form fitting tightly to the curve, remove it and prep it with mold release wax. You could also cover the surface with masking tape before waxing to be extra sure the fiberglass won't stick to it. After waxing, reinstall the form - you removed it to wax it so no wax got on the hardtop, which would prevent a good bond.

With the form prepped and in place, you can build up layers of resin-soaked fiberglass mat inside the form and joining to the broken edge until you've got enough thickness. I would also extend some of the layers beyond the crack on the inside of the hardtop for extra strength. And extend the layers beyond the bottom of the hardtop edge to allow for trimming after the repair cures. You can see the layers of resin-soaked fiberglass mat in the photo of the panel repair above.

For resin you must use either an SMC-compatible polyester resin (hardtops are molded from Sheet Molding Compound, which has mold release agents as part of its chemical composition, so ordinary polyester resin won't reliably adhere to SMC), but I prefer to do repairs like this with epoxy resin, which will bond better than SMC-compatible polyester resin. An epoxy resin I've had excellent results with is West System 105 (https://www.westsystem.com/product-categories/the-105-system/).

After applying enough layers of resin-soaked fiberglass mat to the inside of the form to result in appropriate thickness, let the repair cure overnight and then remove the form. The bottom edge of the repair can be trimmed to the proper length and the surface of the repair will almost certainly need sanding and perfecting with body filler. I use MOPAR hardtop touch up paint after the surface has been perfected.

If any of the above isn't clear please feel free to ask questions and I'll try to answer or explain things better.