Characteristics:

Model Years: 1964-1965.  ***Note*** some of the first 901 (911) cars came equipped with 356 calipers.

Material: Very high Grade Cast Iron. 

Casting Method: Sand

Finish: Yellow Zinc Dichromate

Fasteners: M8x1.25x50 Cap Head Standard Hex. Grade 10.9.  Rare 14mm diameter nuts with lock washers. Oiled Black Oxide.

Pistons: 48mm. Should have numbers cast into the top of the pistons for originality.  Pistons are hard chrome/nickel plated.  Many are finally showing signs of age and should be replaced with stainless steel versions if rusted. Link to stainless steel pistons.

Knockback Mechanism (to maintain a high pedal on non-booster circuit cars): Yes. Internal c-clip. Removable.

Compensating Lines: Yes. No internal fluid passages.  Also commonly called “bridge pipes” or “crossover tubes”.

Bleeder Valves: M10x1 short.  2 bleeders per caliper. Should have pointed end to seat properly.

Fluid Inlet Style: Banjo.  Must have proprietary angled banjo to seat properly.

Mounting: Behind axle.  Notch in caliper pistons should be facing the compensating line inlet by 20˚

Pads: FMSI D31 Pad Size.

Other Identifying Factors: ***IMPORTANT*** If your calipers do not have the following design characteristics (as seen in the photo above), your original 356 calipers have been replaced with a later L or M-Caliper.  If you are sending core calipers back to us for credit, please make sure they are actual 356 calipers.  This is a very common scenario; Owner 1 takes the 65 356C into Dealership A complaining about a sticking caliper.  Dealership A replaces defective caliper with a superseded L-Caliper or M-Caliper of just a couple years later design. 

356 calipers will have a Dunlop license marking by the fluid inlet. The surface will be rough sand cast finish.  They all have deep fins cast through both sections.   They will have a 4801 marking cast into one ½ and a 4802 marking cast into the other.  This simply denotes back ½ (with the mounting ears) and, nose section. 356 calipers usually plate up well due to the extremely high quality cast iron used at the time.