Type Three Tuning Page -- Disk brakes
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>Are there different years of disc brake stuff?
There are three:
'66 to mid '68 -- small caliper, small spindle diameter
Mid '68 to late '71 -- small caliper, large spindle diameter
Late '71 to '73 -- large caliper, large spindle diameter.
There is a 4th caliper (rare, option M594), the giant 4-pot caliper found on
72-73 Variant II Squarebacks sold in Sweden.
The pad for the normal 72-73 Variant and 411 caliper is the same as rear pads on
all 75-90 Volvo 240s.
Cross-drilling and slotting help in releasing gas build-up between the pad and
disc during hot-n-heavy breaking. They also allow water to be channeled away
more quickly. The vented ones can also help in the cooling of the disc during
No, cross-drilling a disc will not crack it unless you use your T3 to race and
brake a LOT, constantly!
Vented discs help in cooling the disc but nobody makes such a disc for our cars.
I would believe the reason is the small thickness of our discs, and thus
calipres, when compared to vented discs which, overall, are much thicker.
Is it worth it? Well, I know that disc pads can come with a slot in the middle
of the pad and this helps with gassing and water dispersion. For the stock T3 a
slotted pad and the stock brakes are very good. My discs are cross-drilled to
help cool them but since I have done no formal testing I cannot say whether this
has helped or not. I do know that my wet weather braking is better. As a custom
modification, cool looks and inexpensive cost all factored together I think it
was worth it.
I had mine done by C.H.Topping & Co. located in California. At the time
it was $35/rotor. They do chamfer the holes. Give them a ring at
C.H.Topping & Co.
520 West Esther
Long Beach, CA 90813