Handbrake & Clutch Cables

TRW’s research suggests that only 2 per cent (4.2 million) of the European car parc changes parts such as handbrake cables on an annual basis. This figure could be higher if workshops were encouraged to check cables more regularly.

TRW Handbrake and Clutch cables are tailor-made for each car and the specific needs of each braking system.

Types of Cable

Braided wires building a rope - Braided ropes building together the cable: high flexibility	Braided wires building the cable: high strength
Grease (MoS2) between the ropes and wires: low friction OE dictates which design to use depending on flexibility requirements

Handbrake Cables - Key Facts

• 674 references covering 61% of the European car parc
• Aiming to be Number 1 in parc coverage with aggressive range extension plans
• 130 new references released in 2011 and over 130 being launched in 2012
• All references are in stock with market leading availability
• Maintenance-free
• Steel wires form a multiple strand rope resulting in enhanced flexibility as the wires can slide over each other
• Coated with molybdenum disulphide (MoS2) to lower friction and improve sliding
• High-quality surface treatment to withstand hard corrosive actions
• Using a multiple smaller wires to make thicker ropes, combined with MoS2, increases cable strength, flexibility and the degree of sliding within the sheath

Clutch Cables - Key Facts

• 254 references
• Aiming to be Number 1 in parc coverage with aggressive range extension plans
• 37 new references released in 2011 and over 55 being launched in 2012
• All references are in stock with market leading availability
• Mirroring OE, a large part of the range have automatic adjusters meaning they can be fitted by one person rather than two 
• Standard cables need re-adjustment from time to time, in order to compensate the wear of the clutch
• TRW cables with automatic adjustment are self-adjusting and maintenance-free
• Spiral rope covered with nylon and molybdenum disulphide (MoS2) as self lubricant
• Trapezoidal sheath for good flexibility and an inner plastic pipe to improve smoothness and protect the rope from rubbing against the metal sheath

Why cables need to be changed

It starts with a little crack: The image above shows that the polyamide cover has been destroyed. Water and dirt have caused corrosion and the outer diameter is expanding. This means that the cable cannot slide freely anymore.

Most common failure:
The parking brake cannot be fully released which can lead to:

1. Overheating brakes
2. Grinding noise (high wear and tear)
3. And in the worst case the car won't move

Less common failure:
The hand brake lever cannot be moved by driver
No hand/parking brake available

How to test handbrake and clutch cables

Test on a rolling road test bench

• No significant dragging should occur
• If a lot of dragging occurs the handbrake cable could be one of the reasons

Remove the drums

• Actuate the hand brake lever and check whether the hand brake mechanism is working properly
• Release the hand brake lever – the shoes have to go completely back to their rest position
• If in doubt disconnect the cables and check the cables only

Always do these tests before mounting new parts