[WyattsRide]

Since my MY85 has been back on the road this past year. I've found that the rear hatch area has developed a water leak when exposed to heavy rain and when washing the car if I concentrate rinsing over the hatch for a long time.

Note: The hatch gasket has been replaced in the last 5 years and 2 of those years the car didn't move from the garage. (you may know why)

The water starts pooling down near the tool panel at the right corner. (facing the hatch from the rear)

Would a misaligned hatch have anything to do with this leak?

Left side


Right side


1. Even if the misalignment shouldn't effect the seal of the hatch. I need to align it correctly. Any good procedures to follow?

2. Any other ideas on why the leak and what to do about it?

Thanks!!

[smiffypr]

Two places to check. 1) Where the spoiler attaches to the hatch. There are multiple studs and screws that go through the hatch and need to be sealed. 2) the quarter-light window seals.
Both can be tested by pouring water in the appropriate area and looking for it appearing inside, be patient though, you will probably have to pour water for many minutes before it shows.
If you take trim off you will see it more quickly.
The hatch seal itself, you should be able to see if it is making contact everywhere, and very easy to test by pouring water into the gaps around the hatch

[WyattsRide]

Two places to check. 1) Where the spoiler attaches to the hatch. There are multiple studs and screws that go through the hatch and need to be sealed. 2) the quarter-light window seals.
Both can be tested by pouring water in the appropriate area and looking for it appearing inside, be patient though, you will probably have to pour water for many minutes before it shows.
If you take trim off you will see it more quickly.
The hatch seal itself, you should be able to see if it is making contact everywhere, and very easy to test by pouring water into the gaps around the hatch

I can rule out the quarter-light window seals. I taped off the hatch first and only applied water to quarter window for several minutes at good pressure and there was no leaking. Then I taped off the quarter windows and applied water to the hatch area. That's when it started leaking as mentioned above.

The spoiler attachment screws are something to look into. Thanks

[worf]

This post is what happens when I post on an empty stomach: total crap.

See 87+-specific post down thread.

And - possibly - pass through for the tail light harness.

I write “possibly” because I’m not sure about pre’87.

On 87+ there’s a rubber plug/gasket/o-ring (it’s weird; don’t know what to call it) that seals around the tail light harnesses where they pass through from the interior of the unibody.

The “plug” is ‘gooped’ from the factory. If the plug’s not installed meticulously or the goop fails water will dribble into the interior.

To test: remove hatch carpets, spare, and tool panel. Hatch open, run water down the left-side rain gutter. If you see water dripping into the spare tire well then there’s your answer. Repeat for right side.

I just looked at the ‘86 parts diagram and it doesn’t have the same part as ‘87+. Nevertheless the test above is good because it may tell you if the problem is the hatch seal or hatch alignment or something else. If water pools then you know it isn’t the hatch.

[Zirconocene]

@worf : I started a whole thread over on TOS and this is the very first I've heard about this particular possibility as a pathway. Sweet. Given the season here I've been avoiding driving my car, due to this issue, so this is a great thing to look into, many thanks.

I'm very interested to see if there's a conclusion to the original question that started this thread, I started with the hatch seal and have been going through some of the other things slowly.

Cheers

[worf]

@Zirconocene , I’ve an ‘89 in the shop with the rear cover off. I’ll post a picture of the “area” ; very easy to see with the cover off, not so much with it on.

[WyattsRide]

And - possibly - pass through for the tail light harness.

I write “possibly” because I’m not sure about pre’87.

On 87+ there’s a rubber plug/gasket/o-ring (it’s weird; don’t know what to call it) that seals around the tail light harnesses where they pass through from the interior of the unibody.

The “plug” is ‘gooped’ from the factory. If the plug’s not installed meticulously or the goop fails water will dribble into the interior.

To test: remove hatch carpets, spare, and tool panel. Hatch open, run water down the left-side rain gutter. If you see water dripping into the spare tire well then there’s your answer. Repeat for right side.

I just looked at the ‘86 parts diagram and it doesn’t have the same part as ‘87+. Nevertheless the test above is good because it may tell you if the problem is the hatch seal or hatch alignment or something else. If water pools then you know it isn’t the hatch.

Dave, this is a very good possibility. I was talking with the previous owner (SteveG OTS) and he mentioned something to that effect when he owned the car. (almost 15 years ago) He said he thought he fixed it and I've never had the water problem until lately. So maybe that "fix" has failed!

I'm going to pursue this first, since it will be easy to try in my garage even in the winter.

I will get back with the results Zirconocene

Thank you again Dave!!

I still need to align the hatch though.

[worf]

For ‘87+ there is a unique failure mode that will allow water to drain into the interior hatch area.

There’s a rubber plug/gasket/o-ring (it’s weird; don’t know what to call it) that seals around the tail light enclosure’s retainer stud where it passes through from the interior of the unibody.

The “plug” is ‘gooped’ from the factory. If the plug’s not installed meticulously or the goop fails water will dribble into the interior.

To test: remove hatch carpets, spare, and tool panel. Hatch open, run water down the left-side rain gutter. If you see water dripping into the spare tire well then there’s your answer. Repeat for right side.

Below is a picture with the bumper cover removed. Arrows point to specific features, top right first and then clockwise:
- where water drains from the hatch rain gutter. You can see the seal and you can see that water will drain straight down
- to the sealing grommet for the taillight enclosure’s threaded retaining stud.
- harness pass through (well sealed.)

[worf]

Dave, this is a very good possibility…

Yeah, maybe not. Look up-thread and see what I did to my first post.

You may have something similar but it can’t be the same failure mode because the pre-87s don’t have the same holes since the taillights aren’t retained in similar fashion.

But, again, the open hatch test, done first, is a good way to split the failure mode search space in two.

[MFranke]

If your car has decorative outer trim around the rear hatch glass where the glass edge meets the hatch frame, the trim may be held on by numerous screws with sealing rings that come up from the inside (remove inner hatch trim to see the screw heads). The penetrations for these screws can be the source of leaks that will drain down toward the back of the hatch and exit near the tools.
The fix is to remove the screws, add some butyl or similar sealant, and screw them back in snug.

[Zirconocene]

@MFranke : You can also buy replacements from McMaster Carr that have new bonded rubber washers: https://www.mcmaster.com/94709A211/ (no affiliation).

Cheers

[Gary Knox]

@worf : I started a whole thread over on TOS and this is the very first I've heard about this particular possibility as a pathway. Sweet. Given the season here I've been avoiding driving my car, due to this issue, so this is a great thing to look into, many thanks.

I'm very interested to see if there's a conclusion to the original question that started this thread, I started with the hatch seal and have been going through some of the other things slowly.

Cheers

If water collects in the area of the rear bumper below the tail lights on the later models and makes a 'puddle', that can lead to water ingress as well. I always remove my tail lights, put some water on that flat section and see where it puddles on each side. I then drill a 3/8" or larger hole in the lowest of the depressed area (actually AREAS, as there is usually more than one low spot on each side) so in the future water will drain out. Mr. Merlin also suggests drilling holes at the rear outer corners, just below the tail lights so if there is water there, centrifugal force will move it to the outside and down the hole.
Gary

[sh944]

I'm pretty sure that "Rennlist" sticker causes leaks... lol

[jschiller]

You could try a light dusting of talcum powder, baby powder, chalk dust, even flour or cornstarch from the kitchen on any rubber that you think may be the culprit. Dust the hatch gasket thoroughly and wipe dry the metal sealing area the hatch should be hitting when closed. Then try the water spray again. The water will wash off the powder where the leak is and let you see exactly the problem area. The powder on the hatch seal will also transfer to the metal around the opening and show you any alignment problems where there is no transfer.

[WyattsRide]

I'm pretty sure that "Rennlist" sticker causes leaks... lol

I think you're on to something there!

Wasn't able to water test anything this past weekend. Thanks everyone for the suggestions.

[Andrew S]

FWIW, I had the same problem as MFranke, water leaking around the hatch glass trim attachment points. (mostly rivets rather than screws for 1980 MY) I was able to force some butyl from a caulking tube into the holes and have solved the leak problem so far.

Andrew