1. Padlocks
  2. Master Lock
  3. Universal Application Padlock
  4. 3/8 Inch Diameter
  5. Keyed Alike
  6. Stainless Steel
Master Lock Stainless Steel Padlock with Shielded Shackle - 3/8" Diameter Shackle

Master Lock Stainless Steel Padlock with Shielded Shackle - 3/8" Diameter Shackle

Item # ML40D
lowest price pledge
Our Price: $23.83
Padlocks
Shipping Weight: 1.25 lbs
Quantity: 
In Stock
Master Lock Stainless Steel Padlock with Shielded Shackle - 3/8" Diameter Shackle 3/8 Inch Diameter ML40D
zoom in icon
slider vertical icon
zoom out icon
Comment field cannot be left empty.
Name field cannot be left empty.

Thank you! Your comment has been submitted successfully. You should be able to view your question/comment here within a few days.

Error submitting comment. Please try again momentarily.

Product Images

In Use/Installed

Customer Photos

Lowest Prices for the best padlocks from Master Lock. Master Lock Stainless Steel Padlock with Shielded Shackle - 3/8" Diameter Shackle part number ML40D can be ordered online at etrailer.com or call 800-298-8924 for expert service.
  • All Info
  • Reviews (61)
  • Q & A (39)
  • Videos (2)
  • Photos
  • Why etrailer?

Master Lock Padlocks - ML40D

  • Master Lock
  • Universal Application Padlock
  • 3/8 Inch Diameter
  • Keyed Alike
  • Stainless Steel


Features:

  • Shielded padlock protects shackle and your gear
  • Hardened steel shackle for extra protection
  • 4-Pin lock cylinder is pick resistant
  • Key can not be removed unless the padlock is locked
  • Stainless steel body resists corrosion
  • Can order multiple ML40D locks keyed alike - select option from the drop down menu

Specs:

  • Overall width: 2-3/4"
  • Shackle diameter: 3/8"
  • Shackle length: 3/4"
  • Opening with shackle closed: 5/8" tall x 3/4" wide


40D - Kit Master Lock Stainless Steel Padlock with Shielded Shackle - 3/8" Diameter Shackle





Video of Master Lock Stainless Steel Padlock with Shielded Shackle - 3/8" Diameter Shackle

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.




Video Transcript for Master Lock Stainless Steel Padlock with Shielded Shackle Review

Rob: Hey, everybody. Rob here at etrailer.com. Today, we'll be taking a look the Master Lock stainless steel padlock. Now, having a padlock on just about anything makes sure that people can't tamper with it. Here we have our padlock on one of our coupler locks, but there is a lot of different uses for this style of padlock. You can use it to lock the door on your trailer.

And you can see versus our old lock, our new locks can give us a lot more security. Even if this we're in the locked position, it's not that difficult to break these. You need a pair of bolt cutters, cut that right there or even possibly just get a piece of metal in there and wedge it apart and break the lock.But as you can see with our Master Lock, there's not really anywhere to get any bolt cutters in there to cut the lock off. And the body of the lock itself is going to be stainless steel, so it is going to resist all that rust and corrosion. Little minor things that I really like about it is that the key will only come out when it's in the locked position.

And the lock cylinder on here has a four pin design so it is going to be pick resistant.Now a few measurements to make sure this lock is going to fit your application. The shank diameter, which is the part that's going to go through the lock, that's three eighths of an inch. The opening here is going to be three quarters of an inch wide and the depth of it when it's closed is five eighths of an inch. You can use it on the toolbox in your trailer or anywhere that you need to lock something up that has a three eighths hole. So here we got our lock on the back of the trailer on the back door so nobody can get inside.

And having a couple of these lashes really nice. We had one on the front of the coupler, the one on the side door and we got the one back here.But I know a lot of you are going to say, "Well, that is nice to have all that security, but I don't want to have to worry about having three different sets of keys." Well, the nice thing about these Master Locks is you can get several of these, get multiple of them, get all the same key so they're keyed alike. That way we can just have one set of keys for one trailer and lock everything up.With all that being said, I'm Rob here at etrailer.com. And that'll finish up your look at the Master Lock stainless steel padlock.


Customer Reviews

Master Lock Stainless Steel Padlock with Shielded Shackle - 3/8" Diameter Shackle - ML40D

Average Customer Rating:  4.6 out of 5 stars   (61 Customer Reviews)


- ML40D
by:

Excellent trailer coupler lock! Rounded design makes attachment quick, easy and tamper resistant. 923657



- ML40D
by:

921169



- ML40D
by:

920065



- ML40D
by:

We travel to several states for horse shows. We purchased this padlock to use with our E Z 5th Wheel Lock. These items sure provide an added sense of security. 871413



- ML40D
by:

I have used these locks before and have been very happy. Fast delivery. 846205



- ML40D
by:

Nice locks. I bought three keyed alike. 794566



- ML40D
by:

REally like these locks which I have now used for a year. I cannot see how anyone ( normal demented crook) could break this lock. My trailer is super safe with this lock securing the coupler. Highly recommend. 792308



- ML40D
by:

I am using during winter and they freeze up. 739757



- ML40D
by:

sturdy lock, smooth operation 733696



- ML40D
by:

This trailer tongue lock is easy to use and it is just grand that the same key works on the tongue lock and ball latch!! I have been buying all of my trailering accessories from these folks for years and I will continue to do so since they have a great products, are knowledgeable, and provide great customer service! D. Link 699247



- ML40D
by:

Very satisfied. Would recommend. 694079



- ML40D
by:

I had my multiple locks keyed the same and it works as described. 654625



- ML40D
by:

Works Great 623207



- ML40D
by:

I received the product as described and at the time stated. Will definitely use them again for future needs. 594687



- ML40D
by:

Fit my enclosed car trailer rear door perfect and matching keys a plus for sure :) 594413



- ML40D
by:

The lock has to hang sideways. Because of this it fills with water and freezes in winter. I had to cut reliefs to drain water. Poor. 566646



- ML40D
by:

I will be towing an enclosed trailer loaded with some rather valuable items on board. These locks fit the trailer hasp's perfectly I am totally confident in their ability to keep my goods on board and safe! Thank You etrailer again! 548133



- ML40D
by:

Great customer service! My order arrived quicker than promised & that’s always a nice surprise. I would recommend etrailer for all RV needs. Thank you. 483396



- ML40D
by:

As per selection offered by etrailer.com of three discus Master padlocks with 3/8" shanks keyed alike, we are very pleased with the quality of the product received, as well as the fact that no hardware stores in the Reno/Sparks NV area carried a three pack of these types of locks keyed alike. This makes for very simple ease of use in our situation as well as having the security of discus locks in our application. Also, no hassles or issues in ordering these locks on line. Delivery info on web site was straight forward, accurate and timely. Will considering using etrailer.com again in the future. 477363


Comments
Fine. Thanks for your concern! Good product!
Sue - 02/20/2019

49708

- ML40D
by:

Good good 468762



- ML40D
by:

Very professional 445771



- ML40D
by:

These locks have worked exactly as anticipated. One of them out of 5 is corroding and is a little hard to open & close, but still works. Still a good product and is nice to only need one key. 444777



- ML40D
by:

Has it really been a year? I bought those products for my wife, she is very happy with all. And if she is happy I'm happy. All work and fit like they are suppose to. 439327



- ML40D
by:

Very good quality at its price! 418407



- ML40D
by:

Quick delivery on a great product...... Thank you 405409


25
62
Show More Reviews

Ask the Experts about this Master Lock Padlocks

  • Can Specific Key Numbers be Ordered for Master Lock Padlocks
    Specific key numbers for the Master Lock Stainless Steel Padlock with Shielded Shackle # ML40D can unfortunately not be ordered; you can still order these padlocks keyed alike by selecting that option from the drop-down menu on the product page but they would not match what you currently have so you would need to use two different keys.
    view full answer...
  • Availability of Disc-Style Padlocks that Can be Keyed Alike
    I recommend Master Lock padlock # ML40D. You can get as many of these keyed the same as you want. Just select the keyed alike option from the drop down menu near the add to cart button. Select the amount you want in the quantity box and all of the locks will be keyed the same.
    view full answer...
  • Availability of 4 Puck Style Padlocks than Can be Keyed Alike
    I recommend Master Lock padlock # ML40D. You can get as many of these keyed the same as you want. Just select the keyed alike option from the drop down menu near the add to cart button. Select the amount you want in the quantity box and all of the locks will be keyed the same.
    view full answer...
  • Replacement Cargo Door Latch Locks and 30 Amp Male to 50 Amp Female
    Sounds like you are looking for a new lock setup for your cargo trailer door latch. The Master Lock Stainless Steel Padlock part # ML40D would be a great option that can be keyed alike. Check out the review video I attached for more info as well. The part number # CAM55185 has a 50 amp female side and a 30 amp male side that should work well for you.
    view full answer...
  • Parts Needed for Keyed Alike Lunette Ring, Gooseneck Coupler, and Hitch Ball Coupler Locks
    To add locks to your trailers that have the Lunette Ring Couplers (which connect to pintle hitch receivers) you will want to use 2 of part # BLTL-60. For your gooseneck hitches you will want to use 2 of part # BLTL-50 for Bulldog/Stallion/Superior/T.E.M. Gooseneck Couplers or part # BLTL-55 for RAM Gooseneck Couplers. To lock the set screw you will want the Blaylock EZ Lock Set Screw Lock on Gooseneck Coupler # BLTL-51. For the traditional trailer hitch ball couplers you will want...
    view full answer...
  • Would MasterLock Padlock Part # ML40D fit in a Hasp with a 7/16 inch Diameter
    The Master Lock Stainless Steel Padlock # ML40D that you referenced has a shackle that is 3/8 inches in diameter. It would fit in a hasp that is 7/16 inches in diameter. It would be tight, but the shackle is small enough in diameter that it would fit.
    view full answer...
  • Can Puck Lock Be Used with Blaylock EZ Lock Trailer Coupler Lock # BLTL-33
    The Blaylock EZ Lock Trailer Coupler Lock # BLTL-33 is designed to work perfectly with a standard padlock, but I think the typical opening size on the back of a puck lock will be a bit too small to fit over the end of its pin/shank. The pin/shank on this lock has a 3/4" diameter, while for example the opening on the Master Lock Puck Lock # ML6271 we have available has a height of just 19/32", which wouldn't allow it to mount over the pin. Your best option is going to be with something...
    view full answer...
  • Can Blaylock EZ Lock Trailer Coupler Lock Fit Demco Channel Style Coupler # DM13203-95
    Yes, the Blaylock EZ Lock Trailer Coupler Lock # BLTL-33 that you referenced does fit the Demco Channel Tongue Trailer Coupler # DM13203-95 that you referenced. The max diameter shackle you could fit through the hole on the 3/4 inch long pin is 3/8 of an inch like what the Master Lock Stainless Steel Padlock # ML40D has.
    view full answer...
  • Can Multiple Master Lock Hidden Padlocks Be Ordered With the Same Keys
    The Master Lock Hidden Padlock part # ML6271 does not come keyed alike if multiple locks are ordered. We do have pad locks with a 3/8" shackle that can be keyed alike, the Master Lock Stainless Steel Padlock part # ML40D but none of them have the same hidden design as the above.
    view full answer...
  • Will the Replacement Handle Latch for Cam-Door Lock Part 158-102 Work With a Puck Style Padlock
    Yes, the Replacement Handle Latch for Cam-Door Lock part # 158-102 will work with a puck style lock like the Master Lock Stainless Steel Padlock part # ML40D so long as the shackle does not exceed 1/2" diameter. I have attached a photo of this for you.
    view full answer...
  • How To Determine Fit of the Lippert Underchassis Double Bin Storage Unit
    In order to determine fit of the Lippert Underchassis Double Bin Storage Unit you need to measure the distance between the two spring seats on the axle. If this distance is 68-1/2" wide then you can use part # LC175180 or if this distance is around 72" wide then you can use part # LC236558. If you have a different distance then modifications would need to be made in order to fit. The Lippert Underchassis Double Bin Storage Unit does not have locks but since the bins install under the...
    view full answer...
  • TL 33 and TL 45 Blaylock Trailer Coupler Locks
    I believe what you're looking for is the Blaylock EZ Lock Trailer Coupler Lock for 1-7/8", 2", and 2-5/16" Couplers # BLTL-33-40D. This has the TL 33 and then what I could find on the TL 45 is that it's the same part as the circular padlock on this coupler lock. This has an aluminum construction so it will hold up really well to the elements and it fits a wide variety of couplers on the market. Attached is a sample installation video for you to check out.
    view full answer...
  • Tow Smart Trailer Coupler Lock Place of Manufacture
    The Tow Smart # 3481213 is manufactured in China. If you're looking for a similar lock that's manufactured here in the US, I'd recommend theBlaylock # BLTL-33. For a compatible padlock, I'd recommend the # ML40D from Master Lock. I've linked to a product demonstration video featuring the Blalock EZ Lock Coupler Lock.
    view full answer...
  • Recommended Trailer Coupler Lock for a 2-5/16
    I want to start off by saying that any trailer lock that you purchase will never be able to fully secure your trailer from a thief. If they are determined enough to bring equipment with them to remove a lock then given enough time they will be able to remove a lock. This will be the case no matter what you what you are looking to put a lock on. With that being said, the Blaylock EZ Lock Trailer Coupler Lock # BLTL-33 that you referenced is a great lock that has received many great reviews...
    view full answer...
  • Master Lock Padlock to Work With Blaylock EZ Lock Trailer Coupler
    The Master Lock 970DPF will not work with the Blaylock EZ Lock Trailer Coupler # BLTL-33; instead you would want to use the Master Lock Padlock # ML40D.
    view full answer...
  • Inner Dimensions of the Blaylock EZ Lock Coupler Lock # BLTL-33
    I pulled the Blaylock EZ Lock Coupler Lock, # BLTL-33, from our warehouse and took some measurements for you. The inside width of this coupler lock is 4-3/4 inches. From the base to the bottom of the pin, it measures 3-1/8 inches (see photo). If you do not have a padlock yet, I recommend looking at the Blaylock EZ Lock Coupler Lock with Padlock, # BLTL-33-40D. This is the same coupler lock, but it includes a stainless steel padlock. You could also just purchase the lock separately as...
    view full answer...
  • Recommended Trailer Coupler and Padlocks Keyed Alike
    For your coupler locks to enable you to get all your locks keyed alike, I recommend the Blaylock EZ Lock Trailer Coupler Lock for 1-7/8", 2", and 2-5/16" Couplers - Aluminum # BLTL-33-40D. This will use the 40D Master Lock Padlock and they can be keyed alike to each other by selecting that from the dropdown on the product page and adding the quantity desired. To get the locks all keyed alike you will do the same thing with # ML40D. The easiest option is to order the total number of...
    view full answer...
  • Recommended Trailer Coupler Locks for Wide Coupler Security
    For your Atwood Channel Tongue Trailer Coupler 80060, I recommend the Fastway Universal Trailer Coupler Lock for 1-7/8", 2" and 2-5/16" Couplers # DT25013KA or Master Lock Heavy-Duty Coupler and Latch Lock Combo for 1-7/8", 2", 2-5/16" Couplers # 3784DAT are both good options. The latter doesn't have any restrictions of the width of the coupler.
    view full answer...
  • Recommended Blaylock EZ Lock Trailer Coupler Lock Compatible with 4 Inch Wide Coupler
    For your 4 inch width coupler, we have the Blaylock EZ Lock Trailer Coupler Lock for 1-7/8", 2", and 2-5/16" Couplers - Aluminum # BLTL-33 which is 4-3/4 inches wide on the inside of the coupler lock. This can be used with the same locks as the Blaylock EZ lock # BLTL-20 that has a width of 3-3/16 inches on the inside. You can use the Master Lock Stainless Steel Padlock with Shielded Shackle - 3/8" Diameter Shackle # ML40D which can be keyed alike to get the desired number of locks.
    view full answer...
  • Replacement Lock for Sears Sport 20-SV Rooftop Cargo Box
    If the lock mechanism on your Sears Sport 20-SV cargo box still operates you may need only part # TH03808, the Lock Locator for the X-Cargo Sport 20 SV Box. Since you mention you do not have the hook type lock like # SR03807 then this is likely to be the part you need. According to my contact at Thule, who made the SV cargo boxes for Sears, the complete replacement lock assembly like yours is not available as a replacement part. You may be best served by installing an exterior lock...
    view full answer...
  • Inside Width of Blaylock Industries EZ Lock Trailer Coupler Lock # BLTL-20
    The EZ Lock Trailer Coupler Lock # BLTL-20 referenced in your question has an inside width of 3-3/16 inches. The overall dimensions on the unit are 2-1/2 inches long, 4-1/2 inches wide, and 5 inches tall. This is a really nice coupler lock that will help deter theft of your trailer. The heavy-duty brackets fit around the trailer's coupler and the raised ball on the platform sits inside the coupler. A steel pin slides through the bracket to secure the lock to your coupler. You can use...
    view full answer...
  • Padlock Size and Recommendation for Use with EZ Lock Trailer Coupler Lock # BLTL-20
    For a lock for the EZ Lock Trailer Coupler Lock # BLTL-20 we actually recommend disc-style padlock # ML40D both of which have a 3/8 inch diameter shackle. I have linked a video review of the EZ Lock coupler lock and in it our video team shows this style lock being used.
    view full answer...
  • Can Lippert # LC236558 Underchassis Double Bin Storage Unit Be Locked
    The bins don't include locks, so you would need to devise some way of locking them. A locking hasp like part # 720DPF with a padlock like # ML40D would be a good solution.
    view full answer...
  • Coupler Lock for Atwood 2-Inch A-Frame Coupler
    The Blaylock EZ Lock Trailer Coupler Lock # BLTL-20-40D is specifically meant for use with Bulldog Collar-Lok-style couplers such as # BD028381. For your Atwood 2-inch A-frame coupler you can instead use part # BLTL-33 and lock part # ML40D.
    view full answer...
  • Lock for Fulton/Bulldog Gooseneck Coupler BDGN240200
    With the Fulton weld-on gooseneck hitch coupler GN24, part # BDGN240200, you can use Blaylock coupler lock # BLTL-50 along with padlock # ML40D.
    view full answer...
  • Recommended Hitch and Trailer Couple Locks that Can be Keyed Alike
    We can get some of it keyed alike but not every piece. I recommend using our etrailer.com locking hitch pin, part # e98881, and coupler lock, part # e98888. These can both be ordered keyed alike to one another. We don't offer any padlocks. Instead I would get two Masterlocks using part # ML40D. They can be keyed alike to each other but not the same as the etrailer.com locks.
    view full answer...
  • Supplementary Lock for UWS 4.8-Cubic-Foot Locker Storage Box UWS01004
    The UWS 4.8-Cubic-Foot Locker Storage Box # UWS01004 has a shipping weight of 28-lbs and an actual net weight of 25-lbs. It cannot be ordered with different locks pre-installed but you absolutely can add supplementary hasps and padlocks to maintain security for the water-quality equipment you need to house within it. We do offer many such lock and hasp parts but the ones I suggest are the Master Lock Contractor Grade Double-Hinged Hasp # 722DPF because it will allow installation with...
    view full answer...
  • Replacement Lock Assembly for a Sears X-Cargo Sport 20 SV Box
    The replacement lock assembly for your Sears X-Cargo Sport 20 SV Box is no longer available. The only option I can think of to secure the cargo box is a universal option like part # ML702D with part # ML40D.
    view full answer...
  • Max Shackle Diameter for Locking the Blaylock EZ Lock Trailer Coupler Lock # BLTL-33
    That is correct. If you check out the attached picture of the Master Lock Stainless Steel Padlock # ML40D (3/8" shackle) installed on the Blaylock EZ Lock Trailer Coupler Lock # BLTL-33 you can see that there is no extra space for a larger size shackle.
    view full answer...




  • Why etrailer.com?

    At etrailer.com we guarantee:
  • Highest quality padlocks for the best price.

    Our Lowest Price Pledge ensures you will never overpay for the parts you need.
  • Real product know-how.

    We make sure that the products we sell are what we say they are, and that they work the way they are supposed to work. Get real advice from a real person who has the knowledge and expertise needed to solve your problem.
  • Most detailed, accurate padlock information available.

    Because we take providing accurate product information seriously, we take our own detailed product photos, demo videos and installation videos, as well as verify measurements, instructions, and vehicle fit information.
  • Installations, made easy.

    We love helping people and have the most highly-trained customer service, hands-on experience, step by step videos and installation instructions.
  • Fast shipping.

    Your order is automatically routed to get out of our warehouse and to your door as quickly as possible. Receive free shipping on orders over $99.
  • Personalized service for life.

    We provide one-on-one, personalized service from the ordering process through the life of your product.
  • Trusted since 1946.

    We've been serving customers since our parts store first opened in 1946 and continue to be recognized by our customers, our vendors and third parties for exceptional service.
  • Returns Policy

    Need to return an item? No problem. Please read our Returns Policy for more information.

Info for this part was:

Video Edited:
Zack K
Video Edited:
Zach D
Installed by:
Jeff D
Installed by:
Robert C
Expert Research:
Jameson C
Video by:
Dustin K
Updated by:
Sarah W

At etrailer.com we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time.