What is the consensus on sealant for roof racks?

[LeesWagon]

So i see a LOT of people mention they used run of the mill, get at any hardware store silicone sealant for roof racks..

I also saw a nightmare of a thread where the guys roof was just rotting away from rust.

So what do y'all think about a more stable product like polyurethane? like what is used for windshields, something like this: Amazon.com: 3M 08609 Window-Weld Super Fast Urethane Black Cartridge - 10.5 fl oz. : Automotive

I see people using butyl tape also, and while may be less of a mess. is kind of an older method to the above.

I should have my roof rack this weekend. So wanted to try and be prepared, but ive never installed a rack before, and after reading all the threads about leaks. has me nervous to say the least. lol.

 

[91foxbody]

+1 for butyl tape and some additional silicone on the bolt threads.

 

[spartacus]

So i see a LOT of people mention they used run of the mill, get at any hardware store silicone sealant for roof racks..

I also saw a nightmare of a thread where the guys roof was just rotting away from rust.

So what do y'all think about a more stable product like polyurethane? like what is used for windshields, something like this: Amazon.com: 3M 08609 Window-Weld Super Fast Urethane Black Cartridge - 10.5 fl oz. : Automotive

I see people using butyl tape also, and while may be less of a mess. is kind of an older method to the above.

I should have my roof rack this weekend. So wanted to try and be prepared, but ive never installed a rack before, and after reading all the threads about leaks. has me nervous to say the least. lol.

That should work. Butyl tape or 3M Ultrapro Autobody Sealant, 08302 is recommended by toyota according to [MENTION=151619]TRD88[/MENTION]

 

[LeesWagon]

That should work. Butyl tape or 3M Ultrapro Autobody Sealant, 08302 is recommended by toyota according to [MENTION=151619]TRD88[/MENTION]

oooo this looks like a good product, looks to be clear, so thats a plus!

I think i will pick up a couple of tubes this week.

Fingers crossed! lol.

 

[Sully888]

I used a mixture of butyl tape (around the top of the bolt and under the rack) and then i used this between the roof and the spacer.

McMaster-Carr

 

[Ryance39]

I did not use anything additional on my LFD rack and have been parking outside in the PNW for more than a year without any issues.

 

[BlackWorksInc]

So if you're using the factory mounting holes to install your rack I'd say get something like butyl tape or the body sealer that was mentioned above me. Both have worked great for me in the past when fixing water leaks on customer's vehicles because of bad roof rack installs.

What I will point out is that it is important to try and get as flat a mounting surface as you can for the feet of the rack to the roof channel, so don't be afraid to trim some excess body sealer to get it fairly flat. You want to minimize the gap the liquid or butyl tape has to take up so it's less likely to vibrate/wiggle and break the seal.

Something else I have seen that proved to be an annoying challenge was that apparently some roof racks use like a hollow tube stand-off to get the rack to sit clear of the sheet metal. Well they don't cap or seal the top of them where the bolt goes through so if you don't do both where it mounts to the body and where it goes through the stand-off, you're just making little cups for the water to collect and drain through the threads/where ever else it finds a way.

I have also had good luck with that thick, closed cell foam strip you get for sealing camper shells onto truck beds. I had a customer who's Tacoma had a rack installed with no sealant what so ever and the inside was soaked and moldy. The stuff is very squishy and seals well, similar to some of the waterproof foam Toyota uses to weather seal some exterior parts. Something like this stuff:

 

[Humble Leader]

the best way to seal a roof rack is to use stainless steel - EPDM bonded sealed washers. butyl tape is an option but bonded sealed washers are specifically made for sealing around threads and preventing moisture from traveling up or down the threads of the screw/bolt

I have used those EPDM washers to mount my pelican boxes (2 of them) to my crossbars (so 8 washers in total I used). had them through multiple freeze/thaw cycles up here in canada and throughout the winter months. I have had zero water intrusion into the boxes. with the heavy salting of the roads up here in the winter, even if moisture /spray got in while driving and dried up, I'd have salt stains in the boxes so from experience I can say those washers work

for those of you that have sherpa racks, they use EPDM washers to secure them as well. silicone does not last long term (depending on climate it can last a long time but freeze and thaw cycles will take its toll)

 

[LeesWagon]

I did not use anything additional on my LFD rack and have been parking outside in the PNW for more than a year without any issues.

nothing at all? this seems pretty risky to me!

 

[rageandlove]

So i see a LOT of people mention they used run of the mill, get at any hardware store silicone sealant for roof racks..

I also saw a nightmare of a thread where the guys roof was just rotting away from rust.

So what do y'all think about a more stable product like polyurethane? like what is used for windshields, something like this: Amazon.com: 3M 08609 Window-Weld Super Fast Urethane Black Cartridge - 10.5 fl oz. : Automotive

I see people using butyl tape also, and while may be less of a mess. is kind of an older method to the above.

I should have my roof rack this weekend. So wanted to try and be prepared, but ive never installed a rack before, and after reading all the threads about leaks. has me nervous to say the least. lol.

Buy a Sherpa rack that doesn't need sealant.

 

[LeesWagon]

So if you're using the factory mounting holes to install your rack I'd say get something like butyl tape or the body sealer that was mentioned above me. Both have worked great for me in the past when fixing water leaks on customer's vehicles because of bad roof rack installs.

What I will point out is that it is important to try and get as flat a mounting surface as you can for the feet of the rack to the roof channel, so don't be afraid to trim some excess body sealer to get it fairly flat. You want to minimize the gap the liquid or butyl tape has to take up so it's less likely to vibrate/wiggle and break the seal.

Something else I have seen that proved to be an annoying challenge was that apparently some roof racks use like a hollow tube stand-off to get the rack to sit clear of the sheet metal. Well they don't cap or seal the top of them where the bolt goes through so if you don't do both where it mounts to the body and where it goes through the stand-off, you're just making little cups for the water to collect and drain through the threads/where ever else it finds a way.

I have also had good luck with that thick, closed cell foam strip you get for sealing camper shells onto truck beds. I had a customer who's Tacoma had a rack installed with no sealant what so ever and the inside was soaked and moldy. The stuff is very squishy and seals well, similar to some of the waterproof foam Toyota uses to weather seal some exterior parts. Something like this stuff:

Thanks for the tips! the LFD roof rack doesnt have those stupid tube spacers. There is an actual block that is used to fill the gap between the weather stripping, and provide a solid mount for the rack. So hoping with the sealer we mentioned should provide a nice even surface to seal everything.

 

[LeesWagon]

the best way to seal a roof rack is to use stainless steel - EPDM bonded sealed washers. butyl tape is an option but bonded sealed washers are specifically made for sealing around threads and preventing moisture from traveling up or down the threads of the screw/bolt

I have used those EPDM washers to mount my pelican boxes (2 of them) to my crossbars (so 8 washers in total I used). had them through multiple freeze/thaw cycles up here in canada and throughout the winter months. I have had zero water intrusion into the boxes. with the heavy salting of the roads up here in the winter, even if moisture /spray got in while driving and dried up, I'd have salt stains in the boxes so from experience I can say those washers work

for those of you that have sherpa racks, they use EPDM washers to secure them as well. silicone does not last long term (depending on climate it can last a long time but freeze and thaw cycles will take its toll)

I agree with this, and did see a thread where someone had used some sort of silicone rubber washers.

However, using these washers does not guarantee water will seep in around the block which the rack mounts to.

So what do you think about using the body sealer around the tubes in the roof, and to fill the gap in the rain channel. place the metal block which the roof rack mounts to. then add a couple of these bonded washers to the FACTORY bolts?

This rack uses the factory bolts, and im pretty sure they already have some sort of washer on there. like a SEMS screw. so adding one of these bonded washers wont affect anything?

 

[Humble Leader]

Buy a Sherpa rack that doesn't need sealant.

So what do you think about using the body sealer around the tubes in the roof, and to fill the gap in the rain channel. place the metal block which the roof rack mounts to. then add a couple of these bonded washers to the FACTORY bolts?

this is probably the best way to handle this. you could use butyl tape as well. you live in texas where you don't have very cold winters and then pretty hot summers so freeze and thaw is not a big concern. but sealant is not permanent and you should inspect annually to make sure it's holding up

my concern would always be water in that channel hanging out near the block spacer that is used and getting past the sealant

rageandlove basically has the best way to avoid this but not everyone wants a sherpa rack which is understandable. when you apply the silicone or tape don't overdo it. you don't want the spacer to be resting on a thick layer of silicone

if the SEMS screw has a removable washer then just remove it and use the EPDM washer. if the washer is fixed to the screw you can still use an EPDM. EPDM will help stop vibration due to the rubber component so you don't need to have an anti vibration or lock washer on top of the EPDM one

I would like to make one edit: EPDM washers are only effective when used correctly. over or under tightening will result in poor waterproofing. the washer is convex and needs to be tightened until completely flat, no more, no less. this may conflict with torque specs

 

[BlakeA]

I installed my Gobi Stealth rack in October according to the instructions which do not call for sealant. No leaks so far. Curious if any other Gobi rack owners have had leaks if they followed Gobi’s instructions?

 

[cbaty08]

I used black RTV when installing my Westcott Designs rack. No leaks after 7-8 months.

 

[LeesWagon]

this is probably the best way to handle this. you could use butyl tape as well. you live in texas where you don't have very cold winters and then pretty hot summers so freeze and thaw is not a big concern. but sealant is not permanent and you should inspect annually to make sure it's holding up

my concern would always be water in that channel hanging out near the block spacer that is used and getting past the sealant

rageandlove basically has the best way to avoid this but not everyone wants a sherpa rack which is understandable. when you apply the silicone or tape don't overdo it. you don't want the spacer to be resting on a thick layer of silicone

if the SEMS screw has a removable washer then just remove it and use the EPDM washer. if the washer is fixed to the screw you can still use an EPDM. EPDM will help stop vibration due to the rubber component so you don't need to have an anti vibration or lock washer on top of the EPDM one

I would like to make one edit: EPDM washers are only effective when used correctly. over or under tightening will result in poor waterproofing. the washer is convex and needs to be tightened until completely flat, no more, no less. this may conflict with torque specs

Thanks for your help bud. i got the 3M stuff on order, along with some bonded washers from McMaster-Carr. hopefully should have everything arriving Sunday for the install!

 

[Humble Leader]

Thanks for your help bud. i got the 3M stuff on order, along with some bonded washers from McMaster-Carr. hopefully should have everything arriving Sunday for the install!

which rack did you get? I have been thinking of a rack system. I like LFD because of how clean it looks and installs. I don't have any plans for a roof top tent so weight is not an issue (just 2 pelican boxes). anything steel though my concern is rust up here in Canada

 

[johnnygraphic]

When I finally do get around to getting a rack, leak problems are one reason why I am going to get the LFD cross bars that fit to the factory rack. I won’t have to mess with any of that. I don’t have any need for a full roof rack. We just need a little extra room for our occasional camp trips.


Sent from my iPhone using Tapatalk

 

[LeesWagon]

which rack did you get? I have been thinking of a rack system. I like LFD because of how clean it looks and installs. I don't have any plans for a roof top tent so weight is not an issue (just 2 pelican boxes). anything steel though my concern is rust up here in Canada

I got the LFD 3/4 rack. Looks like it is about 3-4" shorter than my tent, but should be ok.

If rust is an issue they do offer stainless steel versions of their racks. They also have a forum discount if you mention it when ordering.

 

[Humble Leader]

I got the LFD 3/4 rack. Looks like it is about 3-4" shorter than my tent, but should be ok.

If rust is an issue they do offer stainless steel versions of their racks. They also have a forum discount if you mention it when ordering.

oh nice, I was looking at the LFD cross bars. was going to pickup a couple of them in stainless