1969 Master Cylinder - Part III / 105 Dual Booster Brakes

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Mitch Wolberg is having trouble with his front brakes locking up on his
'69 Berlina after rebuilding his (I assume) dual master brake cylinder.

Stefan Romiti (from Australia) is having trouble with the brakes not
releasing immediately after stopping on his dual brake booster  '74 2000
105 GTV.

*********

Okay, I know nothing about Berlinas in particular and certainly nothing
about Australian '74 GTV's.

Once again this is not stopping me from commenting because I'm assuming
(yet again) both systems are similar to the US '69 dual brake boostered
Round-Tail Spider.

I certainly hope it might be as simple as the hose between boosters, but
suspect that might not work for everyone.

For Stephan's car I can only assume he has the same type of boosters and
MC as the US Alfas used only in '69 and '70.

Stephan, drive the car hard using the brakes a lot. Then pull over and
diligently use a finger to test the temperature of each of the brake
calipers. If only the two in the front or the two in the back are
sticking, I guess it's that particular booster causing the problem.
(More anon).

However, if say the left rear and right front are warmer to a lot hotter
than the others, I guess the (hotter) calipers are sticking and need
rebuilding. However, that doesn't mean if you rebuild say two of them,
the other two won't then become a problem.

In Mitch's situation, I'd carefully get under the car (again) and see if
there is some play in the MC arm to pedal. Be careful here because it
might move slightly, but only because the clevis pin / pins / holes are
worn.

Assuming you're sure there is at least some play, And you're absolutely
sure the MC was rebuilt correctly, I'm guessing it is either your front
booster or your left front caliper is sticking.

I'd give it another spin and check if both front calipers are sticking
or just the left one. If both are sticking And you've replaced the
booster hoses (as previously mentioned by others), remove and rebuild
the front booster.

Pay especial attention to the small steel plunger valve and seal which
operates the diaphragm and spindle beneath the booster housing. The
plunger valve / seal should move freely in their housing.

Lots and lots of luck to the both of you,

Biba
Irwindale, CA USA

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