#yourProject – Puch Brakes – Group 7

Who doesn’t know? Poor braking effect, grinding noise, long pedal path

What does the brake anchor plate and the setting eccentric have to do with it? The anchor plate is rarely straight and the eccentrics do not always perform their function. Our thanks for the impulse for this project goes to an experienced “bunny” in the Ruhr area.

Work effort: 2-3 hours
Material: 0-50 Euro
Tool: standard plus self-construction test facility


Brake anchor plates

The anchor plates are tested in this project. This concerns the system points of the brake pads, rectangle blue and the eccentrics, circle red. If necessary, the eccentrics must be replaced. In the meantime, they are available as spare parts from the relevant dealers.


Anchor plates

Most of the time, the anchor plates are rusty, some are already powder-coated. But are they still straight? Mostly not. In addition to a suitable support pattern of the brake pads to the drum diameter, however, the alignment or centering of the brake anchor plate to the drum is very important for an optimal braking effect.

Some may be familiar with temporary grinding noises in certain driving situations. One possibility is the installation position of the fastening clamp of the rod. Depending on the steering impact and suspension, the rim can be touched here.
Another option is to touch the brake drum on the brake anchor plate. The gap between the anchor plate should be sufficient and even. Blank spots on the outer envelope of the anchor plate and grooves in the brake drum indicate an improved condition. The condition of a brake anchor plate shall be assessed definitively only in the built-in state. “Beautifully painted” does not mean “beautiful straight” at the same time.

The tool

Uses were found in the arms of an old measuring tripod as an adjustable thorn, which in this case was welded with an old drilled nut.

Centering

The tool is mounted on the wheel axis without playing. Thus, the orientation of the brake anchor plate and thus the brake pads can be easily assessed. In addition to the all-round cover, the system points of the brake pads are particularly important. In the case of the front plate, the attachment to the axle leg is considered a reference point for the other systems. With the help of suitable tools such as montiereisen or plastic hammers, the deformation takes place in the desired direction. 

Measurement edge

  • Front axle outer edge top
  • Delay below

Measurement brake pad

  • Plant surface Brake pad

Eccentric

The eccentric places the topping as close as possible to the drum. This should result in the lowest possible pedal path.

Basically, the eccentric pen should still be straight and the pad wearer should be adjusted with it. The eccentrics used at the time were pressed with the anchor plate and have an adjustment square with a key width of 9 mm. They should be turned tightly, which the square with the small key width has often already suffered from. In many cases, nuts with the key width 17 (19) have already been welded on. If this adjustment mechanism rotates too easily, there is a risk of braking in driving mode with the corresponding risks. Experts also manage to adjust the old, original eccentrics on a suitable pressing device again. Another option is to replace new parts available today. The removal of the old part is best achieved by drilling out (drill diameter 13mm, better 12.5mm), or carefully with the separating grinder. After that, the anchor plate in this area is usually to be straightened, as some old eccentrics were forcibly turned over and the sheet metal in the area of the eccentric has warped. The fastening of the new eccentric is optionally done by means of nut fixation by means of screw securing, welding, or blocking by means of a maggot screw.

Setting

By lifting the wheel, the eccentric is adjusted. Turn down from the outside of the wheel=firm. Both pads are easily sanded to the drum by emotionally twisting the eccentric. A short tap of the brake pedal confirms the result. If necessary correct the setting. The brake can NOT be adjusted to a strong effect left/right.


Incidentally

Brake drums have wear limits, see repair instructions. Brake drums can break, especially at the rear with wide and modern tyres.

Brake pads should have the same radius as the drum for optimal effect. For this purpose, there are specialist companies that occupy old brake jaws with the desired radius. If it has to be, each drum with its own measure.

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