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First Line says Disc Thickness Variation (DTV ) can easily develop as a result of minor oversights during the installation process or not taking care during the bedding in process. Follow the correct procedures and you’ll significantly reduce complaints of judder – saving time and inconvenience for technicians and customers.
Excessive use of copper grease on the back of brake pads can lead to serious risk of contamination and before any brake discs are installed, it’s vital the mounting surface of the disc and the vehicle’s hub are clean; free of rust and debris. The hub should be cleaned using a soft wire brush or emery paper, then wiped with a cloth and solvent. The smallest piece of dirt or rust can, over time, can affect the disc and induce Disc Thickness Variation (DTV ), which leads to complaints of judder. This will drastically reduce the life of the discs and void any warranties.
Once installed, the disc run out should be measured before re-assembly of the caliper and associated components. If the run out exceeds 0.08mm, the disc must be removed and the hub cleaned again. If this has no effect, the hub should be measured for run out as well. Hub run out in excess of 0.04mm is likely to cause a problem and should be investigated.
New pads and discs installed together must be bedded in properly to ensure a great pedal feel and promote longevity of the components. When done correctly, associated issues relating to brake squeal and complaints of judder are unlikely.
Borg & Beck BECKTEC coated brake discs have a water based coating using Zinc-Aluminium flakes, which protects the disc inside and out against rust and corrosion. This needs to be removed by performing a few very light braking applications – cleaning off the surfaces without building up too much heat in the discs. Sufficient bedding in then needs to be carried out, to gradually
build-up heat in the discs and pad compound to a point where a thin layer of transfer film is laid
down smoothly and evenly onto the disc surface, minimising the chance of judder.
The bedding in period lasts about 400 miles, advise customers to avoid heavy braking, unless an
emergency, as rapid heat build-up can create thermal shocks, causing surface cracks. When bedding in new pads and discs, it is also important to avoid sitting stationary with the brakes
firmly applied – this can create hotspots, especially if the braking system hasn’t had sufficient time to cool. The hot spots can create an uneven surface, resulting in DTV.
First Line’s Borg & Beck brake kits provide all the relevant components needed, preventing potential issues that can arise from mixing and matching and re-using worn parts.
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