Specialists in Brake Lining
After an intensive and long period of development the new generation of asbestos free materials of brake lining is now widely available. There was considerable difficulty in finding materials to replace asbestos - without huge price penalties. The materials now developed are technically superior to most asbestos based materials. Asbestos free materials of brake lining can now give better wear along with improved stability at high temperature. The benefits gained however, depends on the temperature bands, which are used during the operation of the vehicles brakes. A typical comparison of asbestos based and asbestos free material for brake lining on the following graph shows the degree of improved wear experienced.
Comparison of Lining Wear Rates
Correct fitting for Brake Lining
Rivets should be fitted and clenched in a planned sequence, commencing at the centre of the shoe and working to a pattern towards the ends of the shoe.
When using a riveting machine, the actual air pressures used have to be adjusted in the light of experience to accommodate variation of rivet diameter and materials, but will typically be between 4 and 6.2 bar (45 - 90 p.s.i).
Once fitted, the rivet shank should have expanded to fill the hole in the shoe platform. The rivet hole drilling in the lining however is designed to be slightly oversize in order to avoid this expansion of rivet shank stressing the lining, the clamping of the lining being achieved by trapping it between the shoe and the rivet head. To this end a final inspection should be carried out to ensure that not only are the rivet ends rolled over correctly and neatly without cracking but that the whole clamped assembly is tight and without any significant gaps between shoe and lining. (Rivet tightness can be assessed by lightly tapping the installed rivets with an inspection hammer and the gaps by feeler gauge: These gaps should be zero around the rivets between lining and shoe and no more than 0.015mm (0.006") elsewhere.