Bleeding the Brakes

If you have tried to bleed the system and failed to get a hard brake pedal then follow this procedure. Put a clamp on all 3 flexible brake hoses. These should really be professional round edged brake clamps so as not to damage the interior or exterior of the hoses. In the absense of these then two halves of a round steel rod cut lengthwise can be clamped in mole grips or small G clamps over the brake hose.

With all 3 hoses clamped a hard brake pedal indicates that there is a problem at one of the wheels. Release each clamp in turn until the wheel is located where the fault is. Bleed the system from that wheel with the other hoses still clamped. If there is still no improvement then check if the wheel cylinder is seized or the brake shoes are located and adjusted correctly.
If the problem is located on the back axle then also check if there is a highspot in the brake line that has air trapped in it. You may have to temporarily remove the highsopt by bending the brake pipe to test if this is the cause. This is a rare problem though.

If the brake pedal is still spongy with all hoses clamped then the fault is probably at the master cylinder. Try bleeding from the front offside wheel with the other hoses clamped. Check that the movement of the pushrod is sufficient and that the rubber seals in the master cylinder are intact. In the CB type master cylinder there have been some cases where air has been trapped in the barrel of the cylinder and it has been necessary to raise the front of the vehicle sufficiently to bring the angle of the master cylinder at least horizontal before bleeding from the nearest wheel.

Go to Homepage  Aus   UK  USA