Antenna Leak Repair

I am having water leak in from the antenna mount on the top of my van. Rather than by a new seal I'm thinking I'll take it off, clean it, then apply some sort of sealant to the base and reinstall. After looking through the forums it sounds like this has been done before but I'm not clear what sealant to use. I know silicone can result in some resting does anyone have a recommendation on what type of sealant to use for this repair seeing as it will be on the roof and sealing to the paint. I was thinking of using a urethane windshield adhesive but seems like a bit of overkill for a small job.

CDubz said:

I am having water leak in from the antenna mount on the top of my van. Rather than by a new seal I'm thinking I'll take it off, clean it, then apply some sort of sealant to the base and reinstall. After looking through the forums it sounds like this has been done before but I'm not clear what sealant to use. I know silicone can result in some resting does anyone have a recommendation on what type of sealant to use for this repair seeing as it will be on the roof and sealing to the paint. I was thinking of using a urethane windshield adhesive but seems like a bit of overkill for a small job.

Click to expand...

I like using urethane, I say go ahead with overkill! LoL!

Butyl sealant is the best. You will find it on amazon or HD.
I use it on sailboat. Totally waterproof and does not stick permanently as with urethane. Keep it at room temperature before applying under the antenna base. Tighten and remove the excess with your finger.
-JF

Dicor Lap Sealant is the one most commonly used on RV roofs.

I personally would use 3M windo-weld urethane if available to you. Might be a bit expensive to buy a whole tube just for that small job. But that would be the best to use in my opinion.

Also when you save a partially used tube, seal it real good and put it in the fridge. Hein gave me that tip and it worked well to come back and use the rest of the tube later.

I had the same problem a year ago on my '14 4 cyl... rainwater got in through the disintegrated gasket and fried the circuit board in the antenna. I noticed it when water was dripping down the headliner by the rear-view mirror and the NAV stopped working. When I removed the antenna (simple to remove the dome light configuration - 2 "press-tabs" on the right (passenger) side, and the dome light drops down), the circuit board was totally crusted with corrosion. The gasket had obviously been leaking for a long time. CRAPPY gasket... BAD job MB!

I got a replacement antenna from Eroparts, and it was easily replaced. I used black Butyl sealant on both sides of the new gasket. Time will tell if the fix is permanent. It's obvious that if any water enters the antenna housing through the gasket, it will collect on the circuit board and destroy it.

I'm now thinking that every Sprinter owner might retroactively smear some type of black "goop" on the outside antenna housing as an attempt to alleviate this problem, as the original gasket was very thin and cracked after 4 years of ownership.

One man's opinion that may help others!

Mine was also leaking. MB is using two-side tape to seal the antenna housing. Amazing up to where they can go to save some pennies... I agree with JJolls: resealing the antenna mount should be part of normal maintenance (one time job if using the good product!)
-JF

and here is one more leak. Had the same a few years back, Van was 3 years old. Water came in around the back-view mirror. Complained and dealer ship fixed it. Didn't expect to come from the antenna seal. I will take a look in spring to check again when sealing the clips from the plastic side panels.

Question is, could someone of you give a short desrciption how to access the antenna from the inside, what and how to remove ? Would help me alot.

Thank you.
Johannes

Thanks for everyone's replies seems like butyl is the recommended fix, I have used the tape before but not the sealant. Any tricks to application or links. Amazon comes up with Red Devil 0697GI Rd Pro Butyl Rubber Sealant, not sure I need that much if anyone has a link to something else I'd appreciate it. I think the idea that butyl is not as permanent as urethane is a good thought, in case I need to get back in there and fix something else. I noticed the leak camping as I must have had a slight slope towards the front of the car. Started driving the next morning and notice water coming out of the upper console/dome light. Went up and looked and the seal is trashed. I'd agree that all sprinter owners should put something on it as a preventative measure, seems to be a weak point. Between this roof leak and the one with my AC I can't say any of the Sprinters water seals have been impressive.

Got my butyl tape and technical details from this great sailboat technical site by Rod Collins. Many good info for marine toys but also for van life!

https://marinehowto.com
https://pbase.com/mainecruising/rebedding_hardware

You can buy the butyl tape (good quality) directly from his site.
-JF

CanSprinter11"
Removing the antenna is fairly easy: Always a good idea to unplug the master electric connector by the accelerator pedal before unplugging anything in the Sprinter.

1. To remove the overhead console/light - there are two invisible stainless steel "spring tabs" on the right (passenger) side of the console - use a small and thin screwdriver or putty knife and insert it here in the joint between headliner and console plastic. Once you separate the console from headliner a bit, you can pull it downward SLIGHTLY to see where the tabs are. Press the tabs inward toward the center of the van and the console will drop down. I put 2 small Sharpie marks on the headliner where the tabs are so future disassembly is easier.

2. Unclip the wires from the dangling console. The plugs are color-coded so you can't make a mistake in reassembly. You can now easily see the nut that needs removing here to loosen the antenna.

3. After you seal and install the new antenna, the Console snaps back into place - insert left side of console into headliner and push up on the right side.

The hardest part of the job is figuring out a way to get access to the antenna from the outside of the van - it's hard to reach without stepping on the hood. Some type of "skyhook" or Spiderman would be helpful here!

I had a couple of big drops fall from the eye glass flip down compartment the other day. Today I found and followed JFM’s instructions and easily dropped the console.
Surprise - all was clean and dry even as its been raining all day ? No sign of moisture seeping from anywhere. I wonder if the water drips were from condensation ?
Regardless, thanks for instructions of how to remove the console.

CDubz said:

Thanks for everyone's replies seems like butyl is the recommended fix, I have used the tape before but not the sealant. Any tricks to application or links. Amazon comes up with Red Devil 0697GI Rd Pro Butyl Rubber Sealant, not sure I need that much if anyone has a link to something else I'd appreciate it. I think the idea that butyl is not as permanent as urethane is a good thought, in case I need to get back in there and fix something else. I noticed the leak camping as I must have had a slight slope towards the front of the car. Started driving the next morning and notice water coming out of the upper console/dome light. Went up and looked and the seal is trashed. I'd agree that all sprinter owners should put something on it as a preventative measure, seems to be a weak point. Between this roof leak and the one with my AC I can't say any of the Sprinters water seals have been impressive.

Click to expand...

CDubz:
I've got the same issue in our '08. I'm wondering how the repair went. Did you opt to use the Red Devil 0697GI Rd Pro Butyl Rubber Sealant? Seems like a large tube for a small job. Any other suggestions would be appreciated...

Has anyone had any luck with a shark fin style antenna? Can't seem to find any definitive answers.

As above, I resealed my antenna with butyl rubber purchased from auto supply. A year later its working well. Yes, I too had to buy much more than needed but much cheaper than replacing the expensive electronic control box as well as the butyl rubber cost.

Aggie said:

As above, I resealed my antenna with butyl rubber purchased from auto supply. A year later its working well. Yes, I too had to buy much more than needed but much cheaper than replacing the expensive electronic control box as well as the butyl rubber cost.

Click to expand...

Just pulled the leaking antenna off my 07' and resealed with butyl tape. I had water inside the antenna that was leaking into my dome light.

I'm really not feeling great about the way that the antenna attaches given that the nut you tighten down doesn't actually apply any pressure to the antenna helping to seat the butyl tape.

Is everyone here that resealed with butyl tape still holding solid?

There's no other pieces than what's shown in the photo below, correct? It just seems like a poor design to me that the antenna is essentially just "stuck" on there by the tape.

Thanks!

The nut absolutely pulls the antenna down and helps the seal, the nut has standoffs that contact the roof sheet metal outside the square hole the locator on the antenna goes through, then as you tighten the nut it pulls the antenna onto the roof because the nut is spaced off the sheet metal. If you look when the antenna is out you'll see the small indentions in the sheet metal where the standoffs on the nut grabbed. Unless maybe somehow somebody installed the incorrect nut on your van.

Greta_Van_Gogh said:

Just pulled the leaking antenna off my 07' and resealed with butyl tape. I had water inside the antenna that was leaking into my dome light.

I'm really not feeling great about the way that the antenna attaches given that the nut you tighten down doesn't actually apply any pressure to the antenna helping to seat the butyl tape.

Is everyone here that resealed with butyl tape still holding solid?

There's no other pieces than what's shown in the photo below, correct? It just seems like a poor design to me that the antenna is essentially just "stuck" on there by the tape.

Thanks!

Click to expand...

Do not use butyl tape! It will squeeze out when you tighten or overtighten the nut and with vibrations! Only use double-sided adhesive VHB tape, with an adequate thickness, like the original installation. Then, and as by design, the nut isn't involved in the sealing. Go to Mcmaster-carr and get some.

Repaired my leaking antenna today using 1/8” thick Dicor butyl seal tape. I tried some VHB tape but no success as the thin tape would not fill the gap resulting from the slight roof curvature. Probably why Mercedes uses a thick foam tape. 1/8 thick VHB tape might work. The butyl tape does ooze out the sides as you tighten the retaining nut but a plastic trim tool removes the excess butyl tape. The hardest part is removing all the old seal and glue. Goo Gone worked well to dissolve the final layer of glue.

Dicor BT-1834-1 1/8" x 3/4" x 30' Butyl Seal Tape https://a.co/d/iB6Pqga

gltrimble said:

Repaired my leaking antenna today using 1/8” thick Dicor butyl seal tape. I tried some VHB tape but no success as the thin tape would not fill the gap resulting from the slight roof curvature. Probably why Mercedes uses a thick foam tape. 1/8 thick VHB tape might work. The butyl tape does ooze out the sides as you tighten the retaining nut but a plastic trim tool removes the excess butyl tape. The hardest part is removing all the old seal and glue. Goo Gone worked well to dissolve the final layer of glue.

Dicor BT-1834-1 1/8" x 3/4" x 30' Butyl Seal Tape https://a.co/d/iB6Pqga

View attachment 252770View attachment 252771View attachment 252772

Click to expand...

McMasterCarr has VBH tape in the requisite thickness.

Or, thinner tape can be layered......