We have had a few DBA 048 rotors returned for warranty recently due to brake shudder problems. We have discovered what appears to be common practice in workshops for the HSV pads DB7599 (C5 Corvette caliper) to be exchanged for the less expensive DB1331 standard Commodore pad.
The DB1331 pad will fit in this caliper with a little force but the end result can cause a lot of damage to the disc rotors. The C5 caliper has a built in tension spring to assist in pad retraction and reduce noise.
The spring is clearly shown in the picture above.
The DB1331 standard Commodore brakes also have a tension spring but they are riveted onto the pad backing plate.
When a DB1331 pad is forced into the C5 caliper the pad spring sits on top of the caliper tension spring which generates a great deal of pressure subsequently binding up the floating system of the caliper. The caliper can no longer retract the pad off the disc.
In one case we have found so far the pad kicked over on an angle due to the pressure from both springs causing severe pad taper and irregular rotor wear.
In addition to these problems the pad backing plate is smaller than the DB7599 pad which allows the pad to move around in the pad retainer frame (bracket). If the brake fitter uses an aftermarket pad without the tension spring they will experience severe brake noise due to the clearance in the frame.
The easiest method to detect the incorrect fitting of the DB1331 pads in a C5 HSV caliper is the depth of the rubbing surface created by the pad. A DB1331 pad is approximately 44mm deep whereas the DB7599 pad is 49mm deep.
The result from this setup is that the pad is unable to retract from the disc and continues to rub on the disc. Depending on the pad material either the disc will generate shudder from a material build up or in the case of an aggressive pad it will wear DTV into the disc in a short period of time.
The shudder will increase with speed or driving time as the pads and discs will be constantly accumulating heat.
From now on any DBA 048 disc rotor warranty claims will not be granted if the DB1331 pad is substituted for the correct DB7599.
The first thing to be checked when out on the field is the depth of the rubbing surface on the disc. If it does not equal approximately 49mm then the fitter should be questioned as to the pads being used immediately.
Disc Brakes Australia