How to: - How to install leak proof magnetic drain plugs. | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

How to: How to install leak proof magnetic drain plugs.

Prefix for threads which are instructional.


Moderator & long time member.
Staff member
Elite Explorer
November 11, 2005
Reaction score
City, State
Brooklyn, NY
Year, Model & Trim Level
88 89 93 95 96 Aerostars
Most transmission pans, and metal differential covers don't come with drain plugs. There are companies that sell universal drain plugs which are good, but sometimes tend to leak if they get loose. They have multiple parts, and only have a small opening for the fluid to drain which makes it not the ideal choice if you want to drain your fluid rapidly. This article explains how to install a 1/2" X 20 magnetic drain plug into a 31/64" hole on a two wheel drive A4LD transmission pan.

To get started, there are two types of drain plugs, the regular size, and the oversize which is a little longer.

The black package on the left is the oversize type, and the red package on the right is the regular type.

These are the supplies which are needed to solder the 1/2" X 20 nut into the pan:

This is a two wheel drive A4LD transmission pan:

This is the pan lined up in a drill press before it was drilled. Take note of the mark where the bit is going to make the hole:

The bit is about to go into the pan. It's pressing against the pan:

The drill bit made the 31/64" hole in the pan:

The hole has to be cleaned with an abrasive pad:

The part of the nut which comes into contact with the pan has to be cleaned:

The inside of the pan has to primed with soldering flux paste:

The back of the 1/2" X 20 nut has to be primed with soldering flux paste:

Now it's time to solder the nut to the pan:

This is the inside of the pan with the bolt, and the nut removed. The picture has the magnetic drain plug installed:

This is the bottom of the pan with the drain plug installed:

Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!

For clarification, please elaborate a little bit more on this "paste" you're using -- thanks! Like is it soldering flux?

I didn't want to have the plug as the lowest spot facing the road just in case there is something on the ground as I'm driving. This area was the recessed point of the pan, and is in the rear. When you drive up on ramps, it will tilt the fluid back into that area. I guess it's a safe spot to put it, but it could be placed in the center too.

Does the solder stick good?

I tried this on a piece of scrap metal and I had trouble getting the nut to 'weld"... Are you using any specific kind of solder and paste?
I want to do this, but I am concerned about my soldering ability..

Since you covered my first question which JT asked, why not weld the nut on the outside of the pan? Would seem like mounted with the nut inside it wouldn't allow for draining of all the debris that might be in the fluid.

You have a good point about welding it to the outside. Maybe I'll try this by soldering it to the outside, and use the oversize drain plug to go a little deeper into the pan. Thanks for the tip! To answer the other question, it's the same flux which is used by plumbers or electronic service technicians.

I know nothing about soldering so I just didn't know if it's not something that would be really strong enough to hold the weight of the fluid and bolt, granted the bolt weighs like nothing, but on the outside. I have a drain like this on the very most bottom point on my 5r33E but it's a simple like double bolt setup with a drain plug that goes in the middle...hard to explain I'll see if I can find pictures of it. Anyways, it leaks.

It's like one of those but instead of the wing nut thing on the end the whole bolt comes out.

The nut on the outside would bother me a bit. I think it would be significantly weaker and could get "knocked" off with a good hit. At least on the inside, you have the sandwich effect with the pan in the middle. The nut on inside makes sense to me, but I just can't solder good enough , I guess.

usefull thread
Instead of soldering it you can also use JB weld or another form of epoxy thats what I used.
good stuff and cheap and easy.

wait a minute.......I'm a hvac tech and you can not solder steel to steel using regular lead free plumbing can use silver solder but that takes more heat than propane. I'd like to see that picture up close.

Transmission drain plug

I used my mig welder to install my drain plug! I ground the inside of my pan with a 4" grinder to smooth out the weld and remove any flux or "bugs". And I installed it on the rear of the pan and in the lowest spot so all the fluid will drain out. :)




AKA Magick_Man

post pics

Thanks, it worked...sorry about the resolution. I used my cell phone's camera, I left my digital at work..


Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!