How to Install Weld Rings

Weld rings are an important part of axle brakes. In this guide, you’ll learn what they are, why they’re important, and how to install them.

Outline of Topics:

• What is a weld ring?
• Where do you install weld rings?
• How do you install them on an axle?

This is part of the Couplemate™ Technical Hub unit on Hardware.

What is a Weld Ring?

Weld rings are used on trailer and caravan axles to install drum brakes. Whether you have mechanical, hydraulic, or electric brakes, most modern trailer axles will have weld rings fitted if they use backing plates.

Backing plates typically feature 4 or 5 mounting holes. Bolts pass through the holes on the backing plate and weld ring, fastened with nuts, which attaches your brakes to your axle. Given the different styles of axles and brake available, there are a handful of different weld rings for different applications.

In other words, if you have 45mm square axle with 10-inch electric brakes, you’ll need a different weld ring than someone with a 39mm round axle with 9-inch hydraulic.

So, what type do you need?

Specifically, the axle weld ring you need depends on your:

1. Axle profile (i.e. round or square)
2. Axle size (i.e. 40mm, 45mm, 50mm, etc.)
3. Axle turn (i.e. electric or marine)
4. Brake type (i.e. electric, mechanical, hydraulic)
5. Brake size (i.e. 9-inch, 10-inch, or 12-inch)

Browse all Couplemate™ weld rings here.

Where do you install Weld Rings?

These mount plates are positioned relative to your axle bearing combination. You can use Figure 1 to see where our team welds these plates on an electric turn axle on Holden, Ford, Parallel, and 2T bearings.

Tip: Using a paint marker or etching device, mark where your weld rings are to be mounted. Repeat each side of the axle.

Figure 1. Weld ring locations relative to common bearing profiles (electric turn).

How do you install Weld Rings on an axle?

This is a critical step. Weld rings that are mounted incorrectly will result in consistent braking issues. Refer the job to a qualified boilermaker if required.

Proceed with one of the installation methods below.

Method One: Workshop Installation

1. Trial fit the mount plates onto your axle at the appropriate measurement.
2. Using magnetic clamps, ensure the plates are perfectly square and aligned at 90 degrees.
3. Tac weld onto the axle. Ensure you tac at the four corners of the weld ring
4. Check alignment to ensure the it is in the correct position.
   1. If correct, weld the remaining internal lengths around the axle.
   2. If not, cut your tac welds to remove the weld ring, realign, and repeat until correct. 

Method Two: Field Installation

1. Using the supplied studs and nuts, bolt your weld ring to the backing plate. Bolt securely but not firmly.
2. Slide the bolted backing plate assembly onto the axle, stopping when the weld ring contacts the axle shoulder.
3. Install the drum onto the axle, aligning the bearings on the journal, and tighten.
   1. Greased bearings not required at this stage.
4. Adjust the backing plate so it is concentric with the drum.
   1. There should be about 5mm between the drum and the backing plate edge. 
5. Tighten the brake shoes so they press firmly against the inside drum surface. Tac weld the plate on the four corners
6. Remove the drum, and weld the remaining internal lengths of the weld rings around the axle.