jwb (02/05/83)
On Datsuns (1978 at least) the rear brakes are adjusted when the handbrake
is applied. You can also tell if they are adjusted by the number of
clicks the handbrake makes. It works too as my wife never applies the
handbrake. I was able to engage and disengage the handbrake about 10
times and go from a condition of handbrake not holding (and probably
no rear braking in normal driving) to the nu mber of clicks specified
by Datsun. I think this method is as valid as the American one and
may save backing into trees, ditches, etc. Obviously applying the
handbrake while moving is the equivalent to "evening" the brakes
Jack Buchanan
University of National Champions
Chapel Hill NCpal (02/05/83)
I may be wrong about this, but I think my Honda Accord has self-adjusting front DISK brakes, whereas the rear drums are NOT self-adjusting. I took the car in to a mechanic once to look at squealy brakes, and he used the backward braking trick. I didn't notice any difference afterwards, but then the brakes have always been pretty good. Anil Pal pal@uwisc seismo!uwvax!pal
gary (02/07/83)
Disk brakes are self-adjusting by their nature: no "self-adjust" mechanism is needed.
wookie (02/08/83)
Most disc brakes are considered to be "self adjusting" since the designs did not include springs to return the pads whereas drum brakes use rather strong springs to return the shoes to their resting position. As the disc pads wear more fluid enters the system at the master cylinder to take up the slack and thus the "self adjusting" effect is evident. Drum shoes however have to have the slck taken out by mechanical means at the wheel. There are new designs coming out in disc brakes which are intended to retract the pads somewhat to prevent the drag that otherwise occurs. In the past the drag was considered insignificant and also helped to clean the disc but now of course we are concerned with every possible source of rolling resistance! Keith Bauer White Tiger Racing Bell Labs Murray Hill
dmmartindale (02/09/83)
As Keith Bauer explained, disk brakes are self-adjusting because as the pads wear, more fluid from the master cylinder reservoir takes up the extra volume in the wheel cylinder. Since the pressure on the pads is applied solely by the hydraulic cylinders, this is enough to handle all the wear that occurs. In drum brakes, the shoes are supported at two points - one at each end. One of these is the hydraulic cylinder, and the same sort of automatic adjustment takes place here as with the cylinder in disk brakes. The other end, though, is supported by a mechanical stop of some sort, and this also has to be adjusted to compensate for wear of the shoes. Various manufacturers do different things to provide this adjustment. Some cars have no automatic adjustment at all, so the adjustment is done manually from time to time. Many of the American cars use a mechanism where when you apply the brakes while backing up and the shoes move more than a certain amount, a cable tightens and rotates an adjusting nut a fraction of a turn. If you stop while backing up occasionally and the mechanism stays working, the brakes stay adjusted. The method that works on your car depends on how the manufacturer designed the brakes - there is nothing magic about backing up and applying the brakes. Dave Martindale