L400 Repairing leaks in sliding doors and rear gate

The stains on the inside interior of the sliding doors had been bothering me for quite some time, so I decided to repair the caulking around the sliding doors and the heavily damaged rear hatch glass.

Water seeping into the car through the sliding door?

While I was washing my car in my neighbor’s GS, I heard a clattering sound coming from the sliding door area, so I moved to the back seat and saw that water was coming from the middle of the upper part of the glass of the sliding door!

I’ve known for some time that water was leaking from somewhere in the sliding door, but this time I decided to take the plunge and caulk the gap between the glass and the door at the top of the sliding door because it was soaked to the lining of the sliding door.

Weatherstripping may not be the cause of the leak

At first, is it the rubber (weatherstripping) lining the sliding door opening? I ordered a part, but it is quite expensive.

The one at the top of the opening is $30 for the real one, the one that goes all the way around costs $100, and the two that go all the way around costs about $150.

It seems to be a standard problem that has a pretty good chance of occurring. So I cancelled my order the first thing in the morning of the next day to avoid the possibility of wasting the parts I just ordered.

Materials for repairing a leak are about $15.

I’m going to use about $5 of caulk, about $3 of gun, about $2 of spatula, about $1 of masking tape, and about $4 of backup material. All in all, about $15. It’s about 1/10th the cost of weatherstripping.

The choice of caulking material was any kind of material, but the color of the caulking material was black, so the choice was naturally limited. At first, I was going to use some spatulas (such as ice cream sticks) instead, but they were inexpensive and close to the caulking material, so I bought them in spite of myself. The masking tape is 15m long, but it is just the right length because I was going to re-caulk the edge of the glass of the rear gate as well as the sliding door.

Other sites don’t seem to use back-up material, but I decided to use it because it seemed to be bottomless when I looked into it from above.

Sliding doors are easier than you think.

Wipe the area for caulking at the top of the sliding door with a rag to make the bottom of 10mm. After masking, cut the tip of the caulking tube diagonally and attach it to the gun.

Grab the gun and extract the caulking material while moving it so that the caulking material is slightly higher than the door steel plate. When you finish, scoop it up with a spatula and take off the masking tape.

As a point of caution, you should not get the caulking material on your clothes or car body when you remove the masking tape. Caulking material on your hands is easy to remove, but caulking material on your clothes will not come off.

Rear gate glass edges can be a bit tricky.

Now that the sliding door repairs went well, we can start the repairs of the back hatch.

First of all, we have to remove the old sealant. But it’s hard to remove it even if you poke at it or pull at it, so if you put a utility knife along the glass, it will come out in interesting ways.

Once the old sealant is removed, clean out the grooves to be sealed with Wes and other materials. It’s still dirty because it’s deteriorated and rainwater is getting into the gap. If you install it as dirty, the sealant will not adhere properly, so it should be cleaned in moderation. However, I don’t think it’s necessary to degrease and remove water stains.

Next, masking. Four corners of the glass are rounded. The inner glass is easy to be masked, but the outer glass is very hard to be masked.

Since the masking tape is not so elastic, you may choose a narrower tape .

If you have to use the wide type, you might want to use scissors or something similar to cut into it as you bend it.

I didn’t take any precautions and the masking tape at the four corners stood up.

Be careful not to apply too much sealant.

Unlike the horizontal part of the sliding door, the glass edge of the rear hatch needs to be careful not to overfill the sealant.

If you overfill the rear hatch, you will have a lot of work to do with the spatula. If you remove the excess sealant after filling the rear hatch with too much sealant, it can spill out of the spatula and stain the body and floor of the car.

The sealant should be just enough.

You should be especially careful with the bent part of the four corners where I had a hard time with the masking this time.
When I caulked, I wish I had cut into the standing part of the masking tape at the four corners and knocked the tape down a little.

I knew the four corners weren’t working.

I just did it and removed the masking tape immediately.
The straight lines are better than I imagined, but the four corners are not as good as I expected…not so good.

The part where the cork protruded or became uneven can be cleaned up the next day if you spit on it and rub it with your finger, and the part that stuck out like a burr can be cut off after it hardens completely, so I left it alone for now.

I’m just trying to prevent water from getting in, so I don’t care how good the finish is!
And if you look at it in a brighter place, it looks surprisingly good…doesn’t it?

After Coking

The day after I caulked the door, it rained for about 3 days but the leak stopped immediately.
I knew the leak was caused by a gap in the glass of the sliding door. There was no water dripping on the inside of the glass and the inside lining of the sliding door didn’t get wet, so the leak stopped completely.

I wanted to wash the car once at GS, but it was raining very dirty this time, and there were many cars waiting to be washed at GS car wash after rain, so I couldn’t do the test.

After 3 days, I opened the sliding door to check the caulking, and to my surprise, I found a “bump” on the door.

I don’t know what caused it…I don’t know. Wind? Bubbles?

Well, if it bothers you, you can cut it off with a razor or something, but I don’t have any problems with the current situation, so I’m leaving it alone. I still think it’s best not to drive for at least 24 hours after caulking to prevent this kind of thing from happening. That’s what I thought.