Cleaning your sunroof drains FAQ

[Malleus]

i removed the leading bolt just fine. it was much longer than i expected.

so you are saying water will not cleanly drain out around the captured nut inside the rocker? how deep are you estimating? wouldn't the bulk of the water drain out through the now open hole, and any remainder through the rocker slits or evaporate?

the only way to remove that nut is drill from below to enlarge the hole and the nut breaks free? not sure if i'm ready to take such drastic action!

The weldnut is about 6-mm high/thick. The water has to reach a depth of about an inch in order to flow into the rocker panels.

Those are the two design flaws I referenced above. 1) water in a pocket, in the cabin, that can't get out until (some of it) drains into the rocker panels (which can't get out); and 2) water in a confined space housing electrical connections. Two strikes with one at bat.

No water should EVER be retained INSIDE the cabin. Bad idea all around. You can see all this if you stick a camera in the pockect that's supposed to contain the TWO harness junction connectors on BOTH sides of the truck. Bad idea. This is precisely why Toyota routed those junctions OUTSIDE the pocket in the 100 series, and why Toyota routed the sunroof pan drain hose though the floor on later models, after the 80 series.

Removing the nut isn't the only way to clear the pocket of sunroof drain water, but it is the easiest way. You don't have to drill anything if the nut breaks free when you remove the bolt; the water will then have a way to cleanly drain from that area. I only mentioned drilling the bolt hole if you wanted to install a grommet around it, after you remove the nut. Another option is to simply drill a hole between the two fender bolts and leave them in place. It'd have to be a decent size hole to allow water to flow out and not allow dirt (which is going to accumulate in there) to block it, as is the case in the rocker panels. I'd think at least Ø5-mm.

The best solution is to install longer drain hoses in the front position. This way, no water ever accumulates in the pocket and it stays dry, and so does all the wiring connections that Toyota placed in that pocket. I use rear drain hoses from salvage trucks; they are NLA. I believe they are Ø11-mm ID, but you should check that before you buy hose. I would not use SAE hose. The chance it'll leak is good and the result of the failure is likely to be bad enough you'll wish you hadn't if you do.

The size is important here. Flow in these hoses is not confined pipe flow, it's open channel flow. If you're not an engineer, that won't mean anything to you, but take my word for it - the hose size is important. If it's too small, for example if you thread a hose inside the front drain hose and out the hole in the weldnut, the water will back up in the sunroof pan and you'll have a wet lap for your effort. I know, I tried it. That's why I removed the weldnut on the side that didn't break free, on my DD which was my test case for this solution.

 

[jht3]

i'm very familiar with the sunroof drains being routed inside the front kick panels. my E30 BMW is the same way, and that pocket also houses sensitive electronics like the central locking unit. whyyyyyyyyyyyy

the pass weld nut did not break free. so lucky me? anyways, i sprayed it all down with a garden sprayer and soapy water. its now all drying out. during all this, no water backed up inside the vehicle so not exactly sure how much volume i need to pump in there to simulate last nights rain storm.

i've also seen others route the front drain hoses through the grommet on the inner face of the rocker, with a length of extension hose. both that solution and yours cleanly route water THROUGH the vehicle and not INTO it.

 

[effjay80]

@Malleus - Are these the two body screws you are referring to? Behind the front mudflap, if you have one?

 

[Malleus]

Yep. IMHO, you only need one; there's another 90° from them, on the firewall side, about an inch or two up. It's hidden from view; you won't see it unless you (try to) remove the outer fender.

That little tab between them would have been a great place to put a drain hole. Then the rocker panel drains wouldn't have been necessary. Or, they could have run rear length hose up front and had them hang out of the body - just like they did in the rear fenderwells (look; you'll see it immediately). Apparently the front guys weren't talking to the back guys during development.

 

[effjay80]

Thank you!

 

[COS80]

I don't have any leaks, but I am removing my Prinsu rack today... should I do any of this as a PM, or leave well enough alone?

 

[effjay80]

I have a little over an inch of clearance between bolt and top of slider. Anyone recall ~~ how long those bolts are before I break off the weld nut and have one flopping around with no clearance to pull it out?

 

[effjay80]

I don't have any leaks, but I am removing my Prinsu rack today... should I do any of this as a PM, or leave well enough alone?

Maybe pour some water down your front sunroof drains and see if or how fast it comes out at the bottom?? I have good flow on left but slow go on right.

 

[jht3]

I have a little over an inch of clearance between bolt and top of slider. Anyone recall ~~ how long those bolts are before I break off the weld nut and have one flopping around with no clearance to pull it out?

They are roughly 1.5in long. I was able to remove the bolt even with white knuckle sliders installed. But barely.

 

[effjay80]

And thank you!

 

[fjbj40]

There is a very easy solution for wet floorboards: pull one of the two body screws holding the rear corner of the fender onto the body. You only need one. That will drain the pocket. If you depend on the rocker panel drains, you may be waiting awhile.

If the drain tubes are not really clean, they will eventually fill up enough that water will back up into the sunroof pan, and that will leak. The only way to really clean those tubes, and you really only need to clean the front two, is to remove them and run a brush through them. Yes, you can run string trimmer line in them, but it won't clean them, it'll only clear them.

The front drains empty into a pocket between two sealed body panels. The rear drains exit through the fenders and discharge into free air. They never clog. It's pretty easy to see why.

Toyota's plan was to have the front drain tubes discharge into the pockets, and when the pocket had filled up (hopefully not to the level of the wiring harness connectors installed in those very same pockets!), the water would overflow into a channel leading into the rocker panels, which would then drain via pinch drains between the inner and outer rocker panel sheets. In the event that the pinch drains ever plugged (no, that never, ever happens), Toyota installed removable plugs in the rocker panels to allow (some of) the water to drain out.

The long term solution to leaking roof drains is to replace the front drain tubes with rear drain tubes, and run them though one of the body mount holes that secure the front fender trailing edge. This is the solution Toyota finally used to fix the problem on later models.

This sounds like a lot of work, but it can be done in a weekend, provided you have the parts (spare rear drain tubes).

View attachment 3728835
Photo is driver's side, front is left, rear is right, in the photo. The running board forward edge is immediately forward of the bolts. Doesn't matter which you remove; there is another, hidden, about a foot forward and 6 inches up, on the firewall. There's no danger of the loosening at all. This is my DD and it's been this way since 2017.

Great idea!

I just pulled them in my 93 and out flowed water both sides!

I have a very steep driveway and lately I’ve been backing in. The other day I noticed soaked passenger floor.

Ran trimmer line down, no obstructions, so I tried air next, could hear it exiting but with lots f water.

I pulled the aft bolt for fender and quite a load of water and all my pinch welds are clear. So my steep driveway shows the flaw in the front drain.

Once again MUD knowledge to the rescue

 

[jht3]

dried out the passenger side again. have the front fender bolt removed and the inside rubber grommet. that internal cavity is bone dry..i looked using a mirror.

decided to pull the drivers side front bolt and water poured out. no rain in the last few days and the 80 has been sitting nose down. i did test the sunroof drains by pouring water into the front sunfroof holes, and sprayed water/soap into that front cavity. that was days ago and still hasn't dried out like the pass side did during the same timeframe. SMH.

for the time being i'm leaving both bolts out. but it does seem the permanent fix is to route the hoses externally so water cant ever get trapped in that cavity or the rockers themselves.

 

[duece71]

@Malleus - Are these the two body screws you are referring to? Behind the front mudflap, if you have one?

View attachment 3937482

Very helpful picture, thank you.

 

[effjay80]

A quality replacement extended front drain hose set to route down through the holes would be a great aftermarket kit.

 

[Malleus]

Yep. If only we could get metric hose in this country...

 

[fjbj40]

Yep. If only we could get metric hose in this country...

I do believe Bel-Metric sells the sizes needed.

 

[Malleus]

I just measured several of my OOS (old, old stock) rear drain hoses. They all measure Ø15 ID x 1.5-mm wall. The closest BelMetric has listed is Ø14.5 ID x 3-mm wall. I doubt it'd fit (very well). Wall that thick wouldn't stretch easily, and it is thick for vacuum service, so it's not intended to collapse (or stretch, for that matter).

They might have access to other sizes. Someone would have to call and ask.

FWIW, I didn't do an exhaustive search; there might be something else they have that would work. I used to buy from them when I worked in industry, long ago, but back then they only carried fasteners. It's good to know they now carry more than just nuts and bolts. They were a good suplier, back then. However, I was buying industrial components, not automotive components. Something to keep in mind. If an industrial component fails, a machine is down, for awhile. If an automotive component fails...

 

[Plains Cruiser]

I had my windshield “resealed” but here I am noticing water again after a rain today.

Before I had noticed water at the top, this time it’s at the bottom (both at the edges and some beads in the middle).

I leave on a roadtrip soon… is it practical to lay down some silicone of some kind to help waterproof the windshield base? It didn’t even rain bad today… I imagine driving at interstate speeds during a strong downpour would really bring in water.