Camshaft Repair Kits

Cam kits will generally include the following components:

• Support brackets – Support brackets sit inboard of the wheel end and bolt to the axle housing. The support bracket contains a bushing which supports the inboard section of the cam near the splines that the slack adjuster will be installed on. Support brackets are included if the bushing is not replaceable, so not all cam kits will include the support bracket as part of the maintenance kit. The bushing will be captured within the new bracket.
• Support bushings – For brake systems with replaceable support bushings, cam kits will include the replacements instead of the entire bracket assembly. These bushings may be a nylon plastic or a brass type depending on what the brake design specifies.
• Spider bushings – The bracket in the wheel end that holds the brake rollers and supports the cam is known as the spider. There will be a section that is meant to support the wheel end of the cam shaft near the “S” head of the brake camshaft. Spider bushings will be included and may be a nylon plastic or brass depending on manufacturer specs.
• Bolt in spider support – Like the support brackets, some brake designs will have a bolt in spider support and bushing. This allows the complete replacement of the wheel end support structure for the camshaft. This support area can sometimes be damaged by severe neglect and require the replacement of the entire brake spider.
• Spacer washers – Washers of varying thicknesses will be included in brake cam maintenance kits. The washers are used as spacers to help position the cam and the slack adjuster. There will normally be room for adjustment at the snap ring areas of the cam to shift the cam and the slack adjuster slightly, so everything lines up correctly.
• Seals – Seals are used in the brake spider to keep grease contained in the brake cam bushing. Grease seals function as a one-way valve and they must be installed correctly to retain the grease. Incorrectly installed seals may allow the grease to enter the wheel end and foul the brake shoes.
• Shield washers – Most kits will include a washer with a large outside diameter or shape. These washers are used inside the spider between the camshaft “S” head and the spider. This washer protects the cam from wearing on the spider or damaging the seal.
• Snap rings – The snap rings are used to secure the cams at certain locations along their length. One snap ring is normally used at the back of the spider to hold the brake camshaft in the wheel end and hold the position of the seals, bushing, and washers. Another snap ring is used on the splines of the cam to hold the slack adjuster in position against the support bracket and bushings.

Cam tubes are another option for some vehicles. Cam tubes contain support bushings and seals in a pre-assembled tube that can make the job of changing cams faster and easier. Instead of spending time pushing bushings in and out and installing seals the cam tube can be unbolted and a new assembly bolted in. Replacement cam tubes will only be available for some OEM applications although there are aftermarket replacement options than can allow you to convert most trucks and trailers to cam tubes. Not all cam maintenance kits will have the same components or number of components. This is decided by the brake system designer when the system was built. Cam kits matched with their cams will contain the parts that are necessary to correctly replace the cams and return the brakes to their original operating conditions. Some knowledge of the system you are working on will be helpful as some cams will have multiple maintenance kit options depending on the setup of the axle. If you are having trouble finding the correct cam kit for your application, please reach out to us at TruckSpring.com or give us a call at 1-800-358-4751. We will be glad to help you find that parts that you need.