Replacing sheet metal screws on the tralier

[billtebbutt]

All,

Well, the Haulmark trailer is becoming about as *vintage* as I am - its seen almost 25 years of racing use, and I am finding a number of long delayed maintenance jobs are in my future.

One of the ugly jobs is to methodically remove and replace all of the #10 self drilling screws that were used to mount the ally sheet walls to the frame of the trailer - after all these years they have rusted badly and are beginning to stain the aluminum. They are barely 5/8" long when you include the drilling tip in the length.

My thought is to use the exact same, pan headed fastener except in stainless. Surely there are other, better ideas amongst the group (or I thought I would at least ask before installing literally 1,000 of these!)?

cheers,
BT

[EYERACE]

stainless for sure.
as to being #10 (grip width/diameter/whatever it's called) old rusty screws were - maybe try a tiny tiny bit wider in a metric for enhanced grip on both pieces of metal

[Purple Frog]

One possible problem: If you remove a #10 old screw and insert a new #10 you may find that it doesn't tighten. You may have to use #8 to get proper grip. Or, possibly insert a dap of sealant/adhesive in each hole before inserting the new #10.

[Craig71188]

Have done this exercise twice (two different trailers)...

Yes, stainless screws bought in bulk online (forgot who I used)
Square drive head is much easier to use
Pan head is not a bad idea if available in the correct drive.

I used the same size as I took out, did have a couple strip. I suppose one number size larger is an option.

[romoman]

Lots of places probably have them. These guys are racers and sell to a lot of trailer companies. It might be worth talking to them. I have no idea on the price https://www.engcomponents.com/fasteners

[Joefisherff]

BT,

I need to complete the same exercise on my Haulmark trailer, please keep us posted on what path you head down and any best practices you learn from the process.

Thank you,

Joe

[Rick Kirchner]

rivets

[Onebadbug]

My trailer used "double square", which it seems only trailer guys use.

https://www.tacomascrew.com/Product/083-502-1



https://a.co/d/gmwd18Q

[tlracer]

Bill - stainless steel should not be used directly with aluminium as it will result in galvanic corrosion of the aluminum, especially on something like a trailer that will get wet:

https://www.albanycountyfasteners.co...-and-aluminum/

Either using a non-metallic washer or a corrosion inhibitor such as Duralac will help to minimise later problems.

[Rick Iverson]

rivets

Yep

[Rick Kirchner]

After spending a month replacing all the fasteners and sealants under my RV's top edge seal/gutters, I can confirm that SS in contact with AL will make a mess.

They used self-drilling screws, and everywhere a screw went through the gutter the powdercoat just de-laminated.

I did replace them with more stainless (because rust is just as bad) but I dipped each screw in paint as I put it in (we used to do this to rivets on missiles).

[billtebbutt]

Bill - stainless steel should not be used directly with aluminium as it will result in galvanic corrosion of the aluminum, especially on something like a trailer that will get wet:

https://www.albanycountyfasteners.co...-and-aluminum/

Either using a non-metallic washer or a corrosion inhibitor such as Duralac will help to minimise later problems.

Didn't think of that - thank you!

bt

[tlracer]

Happy to help, Bill...we limeys have our uses

Link below for Duralac, if needed:

https://www.silmid.com/us/sealants/j...various-sizes/

[jrh3]

After spending a month replacing all the fasteners and sealants under my RV's top edge seal/gutters, I can confirm that SS in contact with AL will make a mess.

They used self-drilling screws, and everywhere a screw went through the gutter the powdercoat just de-laminated.

I did replace them with more stainless (because rust is just as bad) but I dipped each screw in paint as I put it in (we used to do this to rivets on missiles).

Zinc chromate if you’re an old aircraft guy.

[evildky]

One possible problem: If you remove a #10 old screw and insert a new #10 you may find that it doesn't tighten. You may have to use #8 to get proper grip. Or, possibly insert a dap of sealant/adhesive in each hole before inserting the new #10.

Screws don't work that way. Wire and nails yes, but screws go the other way. A #8 screw is smaller than a #10.

[EYERACE]

Learn something every day......that's part of why ApexSpeed is great.........SS vs. Alum. I have not much experience in such work but at first thought the SS sounded good.

I forget if my bolts were SS or Alum but.........
When I installed large bolts through the side of the alum box trailer for the tire rack install, I at least isolated them from the outside surface with thick rubber gromets under the heads for waterproofing before putting sealer over and around the heads. All has been well for about 8+ years since.
Now I need to break out the magnet tool to check, SS?

[DanW]

Now I need to break out the magnet tool to check, SS?

It depends on the grade of stainless. Most fasteners for marine use are 300 series and non magnetic, or if work hardened, very slightly magnetic.