Best practise riveting sequence for CV brake platforms
The integrity of a commercial vehicle’s (CV) braking system depends heavily on the correct attachment of friction material to the brake shoe platform for the drum brake. Riveting remains the most reliable method for securing brake linings, especially in heavy-duty applications. Improper riveting can lead to premature wear, reduced braking efficiency, and safety hazards.
In this article, Scott Irwin, head of technical training at TMD Friction – the manufacturer behind premium brake brand Textar – explains the correct riveting sequence and essential inspection steps for brake platforms, how to perform such tasks and why it’s safety critical to follow this process.Brake fluid: a vehicle’s lifeline
Preparation is Key
Before starting any work on the brakes, it is important to wear the correct workwear. A dust coat or full overall is advisable and will protect clothes; safety boots are essential and should always be worn. Rigger gloves, or other suitable types, are also recommended and have become standard practice in the workshop.
After removing the linings, it is very important to inspect the brake shoe platform. Typical problems to look for when examining the old, used brake shoe include:
• Punch damage holes
• A heavily rusted platform
• Bent or deformed platform
• Corroded welds
• Split welds
• Worn cam roller location
• Worn anchor pin location
You should identify any of these issues, where possible, before carrying out any work. Some may be more obvious, such as excessive corrosion. In the case of bent or distorted brake shoes that are un-serviceable, these must not be relined and should be scrapped using the correct methods.
Check the Brake Shoe for Concavity
It is unlikely the shoe platform will be perfectly flat, and it is accepted there may be hollows or a continuous hollow down the centre where the platform is joined to the web or webs. However, excessive concavity, in which the lining is forced to conform, will cause problems, including longer bedding-in time (due to limited initial lining to drum contact), and the need for extra force to clamp the linings down – resulting in the lining cracking.
You should check for concavity with a straight edge and feeler gauges. The exact limits on concavity should be observed. Below is Textar’s guide, but you should always check the manufacturer’s data:
When the old lining has been removed, the shoe must be cleaned to ensure a thorough inspection can be carried out. The inspection should check for:
• Unevenness due to rusting/corrosion, which could reduce the strength of the shoe.
• Physical damage/warping, which could result in an uneven braking surface.
• Damage on any of the anchor points or webbing, which could result in a reduction in strength.
• Rivet holes for damage and wear.
Preparation Before Riveting
While the inspection will confirm the shoe is suitable for relining, it may still be necessary to prepare the lining platform to ensure maximum contact between the platform and lining.
Often, ‘shoe preparation’ is carried out to provide a cosmetically pleasing shoe, for example it is cleaned and painted. Although this is highly desirable in the overall process, the fundamental purpose of shoe preparation is to enable the correct fitting of the mating parts e.g. the shoe and lining. This can be achieved by using a cleaning agent, de-greasing or shotblasting.
The most efficient method of dressing the platform is by using a sander or a linishing machine of the belt or disc type to ensure all the high spots are removed.
Paint Protection
Once the shoe has been both visually and dimensionally examined, and is judged to be serviceable, it can now be painted. This is an essential process to prolong the life of the brake shoe in service and is typically carried out by either paint dipping or spray painted.
The paint must not be too thick on the area for relining, and the shoe platforms should be cool before painting.
Correct Brake Lining Selection
It is very important you fit the correct brake lining or linings to the brake shoe, as in some cases it is possible to fit the linings either the wrong way round or in the wrong position on the shoe. Check the edge of the old brake linings to see if the part number you require is indicated.
If you are new to relining, sketch the position of the lining on the shoe beforehand. Shoes from the same wheel set may have different lining lengths; one may cover the entire shoe, while another is shorter with two unused holes. Make sure to reinstall each shoe with its original lining configuration.
If fitted incorrectly, it will dramatically affect their performance when fitted to the vehicle. With experience, this becomes more obvious, but if in doubt, always take advice or visit Textar Brakebook.
Textar Brakebook has detailed information on the correct linings, showing simplified pictures to help make the correct choice. It also has several technical tips to help with the relining process. If in doubt, call the technical helpline for further advice from the brake lining manufacturer.
Rivet Types and Selection
Select rivets that meet standards such as BS3575 (semi-tubular copper/steel) or DIN 7338C (fully tubular ways). The rivet material should be copper, brass or steel for durability. Details of the different rivets can also be found on Textar Brakebook.
Correct Riveting Sequence
The correct riveting sequence must be followed to ensure the lining is secured correctly on the shoe platform. It is vital the correct lining(s) for the shoe is used and the right length of rivet to suit is inserted, as outlined at earlier stages of the process.
While it would be ideal if shoes were always the correct thickness and the suggested rivet fit perfectly, this isn’t always the case. Variations in shoe platform thickness, caused by corrosion or inconsistencies in the casting process, means you may need to adjust rivet selection. The castings on some older shoes can result in having to use several rivets.
There are various ways to put the rivets into the brake shoe, and some reliners prefer to put them in one by one. However, the best method is to put all the rivets in place and then tape over the holes with masking tape.
Again, some reliners fully tape over the holes, and some half-tape them, which is a better option as this allows the weight of the shoe to push past the tape more easily.
Whichever method is used, the next stage is to successfully reline the brake shoe using the correct riveting tools, and using the correct amount of rivet force.
Recommended Sequence for Riveting
When relining brake shoes, it is important to start in the centre of the brake shoe and work diagonally outward as shown below. The procedure prevents excessive lining/shoe gaps and friction material fractures.
Final Inspection
Lining/shoe gaps should not exceed 0.006” (0.15mm) beyond the first brow of rivet holes. Gaps more than this can result in security and/or brake noise.
Make sure that no friction material cracks are visible. This could indicate excessive riveting force and/or brake shoe condition. Finally, you can give a visual check that the rivets are secure and their rollover is neat, without splits.
Check the lining is in securely by lightly tapping the friction material with a metallic instrument, such as a small hammer. A high-pitched response indicates an insecure lining, whereas a dull thud would suggest a secure lining. Although, if the brake linings have been relined and checked as per our best practice procedure outline, then these issues will not occur.
Why it Matters?
Correct riveting and thorough inspection guarantee brake reliability under extreme loads, reducing downtime and enhancing fleet safety. Following these best practices aligns with OEM standards and regulatory compliance. More detailed CV relining training is available from the Textar Virtual Academy.
