Repairing FJ40 roof leak

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Jan 8, 2003
I just bought a 1976 FJ40 that is in really great shape. Most of the weather stripping has been replaced, including the seal under the top. I noticed after washing the truck that the roof liner was wet around the inside edges. I then noticed the water stains on the ceiling pad, so I know its been leaking for a while. I believe that the water is coming in where the fiberglass seals to the metal rain gutter.

I've seen a couple of posts in other forums, but I thought I'd ask here if anyone has my particular problem. I am not sure how the top attaches to the gutter. Visual inspection looks pretty clean, with a few small cracks. Maybe a rivet hole is the culpret?

Would anyone suggest removing the top and resealing the entire thing? Or can I get away with applying a sealant in the gutter? I do not want to fill the gutter so that it no longer functions.

Other sugestions? Thanks! :)
There are rivits that attach the fiberglass top to the metal all the way around.
Cheapest way to go is probably seal up the rivit you think is leaking with some caulk or clear silicone. look for any small cracks in the fiberglass that may be helping the leak come in.

More expensive would be to buy a weather stripping kit specifically for this. I know CCOT has them on the web site. &nbsp:Dont recall how much they were or how labor intensive it was, but you would end up replacing all of the rivits, going this route.

Hope it helps
I need to replace the gutter channel on mine. &nbsp:Does anyone have any suggestions on how to install the aluminum rivets. Would a rivet tool used on farm equipment hay cutter sickle bars work?
In my 76 fj40 the PO mounted these custom speaker brackets in the cab in the rear corners for the hard top. Water leaks horrible where he bolted the speaker brackets are. Could I just take off the speaker brackets and silicone the screws and screw them back in and seal up the leak?? Or will i have to seal it from the outside lip??
if the speakers are bolted in, pull the bolts, use a rubber washer on the outside beneath the regular washer, and upt a dab of silicone on there too. Should end up leak free then...should...

IMO, just about "any" rivet tool would work to reattach the hardtop.
I too, once suffered the old leaking roof. I had planned on having someone make a new raingutter and remove the fiberglass panel, rivet the new gutter and install. Pain in the neck, never did it. I have since tried all kinds of fixes, silicone, glues, name it, I have tried it. My fix was clean, quick, and should (I hope) last the test of time.
First, clean the gutter and top on the outside of the vehicle really good. I mean clean enough to eat off of.
Next, secure all the loose rivets. Remove the bad ones, drill then out. I replaced the ones I neede to with new ones. I used aircraft rivets, part # MS 20470-4-8. I cut them to the length I desired, then used a pneumatic rivet gun, and was real carefull not to crush the fiberglass. I suggest trying a test on something else first.
After the glass and gutter were secure, and tight, I mixed up a small batch of resin, fiberglass type, and "filled" the gutter on the outside of the vehicle. I let it cure good, checking for leaks on the inside of the vehicle. There were a few small leaks that I had to "stop". use what you want, I think I used tape to form a pool.
After it set good, I repainted the whole top with 4 coats of marine paint. "petit" was the name of the paint. I used gloss white.
Results, looks like a million damn dollars, and it does not leak. not for two years anyway.
There is also a 3M product called self sealing seam sealer that I would try, but hope I never have to.
Good Luck, Richard
Richard - when you filled the gutters, they lost their original channel rain water, right? Is this a problem for you now?

If you where careful about how much you put in I bet you could keep the functionality of the gutter. It just would not be as deep. Another option for fixing the roof (especially if it is a problem in the center) would be to use some of the same products that are used to patch and reroof a motorhome. You should be able to find one that is pretty cheap localy.
My top was in bad shape with holes drilled from the prev owner. I took some fiberglass and some resin and fixed the holes. I added resin to the rest of the top and it works great. the only thing is the work time is short so you need to work kinda quick. if you have worked with fiberglass befor it would help. the good thing about it is that its hard and will last a long time pluss it smooths things out so less prep work.
I think everyone has had to deal with this 'leaky rain gutter' issue (at least those of us who live in the rain 11 months of the year)! Every summer when I have my hard-top off, I innevitably have to pick the sealant out of the fiberglass to metal gutter groove (the same sealant that I applied last summer). First time went well, except I may not have been anal enough with the prep, and the automotive body sealer seperated from the metal (hitting a few trees and caving in the metal gutter didn't help either). Next year, I installed a friends (ie borrowed while he was travelling) safari rack (with Thule gutter clamps). After an unfortunate incident involving my cruisers new height and an inmovable underground parking lot, the Thule clamps peeled the gutters the other way (oppositethe way the trees caved them in!). To be fair, the trees & roof rack were my own fault, but the fact that you can't clean out (old paint/rust, dust/debris/etc) the gap between the fiberglass cap & the metal gutter, means that if it ever starts leaking, it will leak forever!

Our neighbour at the cottage live in Ireland most of the year. He gave my dad some ~5inch cutoff wheels for the angle grinder, but they are only 1mm thick. Perfect for trimming fiberglass! If water has been sitting between the fiberglass flange & the metal gutter, there will be rust! There doesn't exist any sealant (save 'filling' the gutters completely with resin) that will stick to a scaly, rusty, dirty surfaces (at least for the 10+ year that we expect it to!). &nbsp:Do your self a favour; take the thin cutoff wheel and (verticallly) cut a 1/4 to 3/8 inch slice off of the perimeter of the fiberglass cap (carefull with teh depth of cut; dont' go through steel). You can even cut into the flange part of the rivet heads if that doesn't bother you too much. This leaves a nice WIDE gap that you can scrape (sharpened putty knife, files, etc) down to bare metal (no rust!!!) and put a fat 1/2 inch bead of automotive sealer down (and get it right into the gap, rather than just laying it down on top of the gap). Just make sure you paint it or the UV will cook it in a year (or less if you live in the desert!).

(sorry, I gave up on the ASCII (or is that acssi?) pic.)

if this can stand up to BC rain it should be good 'nuff for anyone!

Good luck !!
hey guys,

i spent all of last semester workin on my hardtop, especially the raingutter. if at all possible i would stay away from sealants/silicone. they are quite possibly the biggest pain ever. a PO had just gooped the stuff on the entrie left side of my gutter, and it's real job to get the stuff out well with out disassembling the gutter.
i ended up doing this. i took the gutter off (just ground off the rivets. and you can buy enough to put it back on from CCOT for 4 or 5 bucks) and worked on it while i did some crazy fiberglass work on the dome. holes galore. used fiberglass jelly (works awesome, comes in a can. a lot more sculptable than regular resin.)

i'll get back to this post later on. i've got a 9:30 class.


email me if you have any questions, i'll see what i can do.
hey again,

i pulled off the whole raingutter. took some measurements off the front piece (it was almost totally gone) and fabbed up one out of sheet metal. it took a while to bend the lip and get it to look right, but after it was done, it really did look nice. *** i have that front piece for sale if anybody wants it*** then i cleaned up the rest of the raingutter, patched a couple holes, and welded the pieces back together.

i ended up finding a really nice fiberglass dome with a raingutter in great condition about a week after i finished with this. the price was right, so i just bought it instead of finishing up mine. (had a lot of sanding and painting ahead of me.)

in my opinion, taking the raingutter off, repairing it, and then using the rivet kit is the way to go to totally stop the leakage. if you want, you couple put a small amount of sealant on the edge of the gutter, along the line you're riveting.

I know a guy who has hard top sides but a canvas top. It seems to work well. Has anyone ever seen this before? I was wondering if it was a home made thing or if it was something you could buy.
Air powered wire wheel to clean the gutter. Replace any loos rivets. #M Drip check is the proper sealant, not silicone. Dripcheck is a thick liquid, it penetrates a little, and flows into the los spots resulting in a nice even finish, and leaves the rain gutters "guttering!" Chefout
Thanks everyone for your responses.

I notice that the 3M site labels Drip Check as good for vertical surfaces, so would one of their other marine paintable sealants work even better?

About the surface prep - I can't see taking a wire wheel to it, because there are no huge cracks or chips, and I can't see any loose rivets. Just small cracks in the paint around the rivets. After the wire wheel, I'd have to repaint the top.

I think I'm going to try one of 3M's other paint on sealants, and I'll let you know how it works.
I've gotten all of the old sealant out of the gutter and decided to cut back the fiberglass so that I have a larger groove to reseal.  I am using Seam Sealer by McKanica.  My plan is to put one bead of sealant in the metal groove, and then another bead over the rivits, smoothing out the entire application so that the gutter is still sloped and not completely full.

My question on prep is should I treat the bare metal with some rust protectant before sealing?  There is only one spot with anything that looks like rust, and I got most of it off.  The rest looks shiny.

Also, I am not planning on repainting the top for a while.  The sealant will not show in the gutter.  Is it necessary to paint over the sealant with a primer?  Does anyone have a product recommendation, or will whatever Schuck's sells work?

There are rivits that attach the fiberglass top to the metal all the way around.
Cheapest way to go is probably seal up the rivit you think is leaking with some caulk or clear silicone. look for any small cracks in the fiberglass that may be helping the leak come in.

More expensive would be to buy a weather stripping kit specifically for this. I know CCOT has them on the web site. &nbsp:Dont recall how much they were or how labor intensive it was, but you would end up replacing all of the rivits, going this route.

Hope it helps
My Toy was just three years old when I got it and the metal flange that is riveted to the fiberglass was badly rusted. I was in Eureka Ca. at the time and it rained almost daily. The water pored in around the back.

Over the years I tried gutter seal, bondo and more glass to no avail. For about 8 years I had the top off and used my homemade rag top.

A few years ago I redid the hard top that had been sitting out for those 8 years.

I used 1/8 inch sheet metal to make the flange and riveted it too the glass top.

I left the metal flat and molded fiberglass cloth around the edge so it does not have a drip rail.

I then ran bead of butile rubber around the top edge of the body and screwed the fiberglass top on.

I took some time for the rubber to cure but the top doesn't leak.

If the metal flange is rusted out on your top then I doubt you will have lasting luck with sealing it.
Hi, Prep work is the key,and least fun. Most products that are good are not cheap. Don't use silicone ! Ive used the seam sealers by 3m and had good luck, follow directions to the letter. I like using these products in a hotter environment 80 plus degrees because they tend to flow better and self level ,easy to do in Texas . Mike

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