Mark Anderson

I only have one 9" but my local rebuilder has been pretty quick

Kiwi928S4

Hi Mark, Are the 10 inch RHD ones the same as the LHD (1991 S4)?

Cheers

ken

Adamant1971

I will take one for the 78, assuming it’s a 9”

The Forgotten On

78 and 79 use the 9 inch, you're good.

Mrmerlin

Note the 9 inch booster was superseded to 10 inch,
because it did not provide enough braking force.

NOTE if you remove the 9inch booster replace it with a 10 inch,

NOTE this upgrade also means you need a new clevis to screw onto the booster piston inside the car,
the 9in clevis is shorter than the 10 inch ,
This was done to make RnR easier to do,
Also minor metal modifications needed to the inner fender well to make the 10in. fit ,
usually 3 hammer blows does the trick

Petza914

I have a 10" I removed from an 81 if someone needs it cheap for a rebuild or core. Don't know if it is good or bad. As luck would have it I had ordered a brand new one for under $300 for the job a few months ago, right before they seemed to go NLA.

Mark Anderson

maybe so but for those restoring early cars the original parts are a plus. Like original radios, its not because they sound better.

Adamant1971

For this 78 we want to stay original. Mark I will shoot you an email. Adam

Mrmerlin

Well I guess its good that we have the choice of 9 and 10 inch booster,
BUT I doubt someones gonna be measuring a brake booster for originality,
its really a difficult part to measure while its in the car,
as first you might want to remove the air cleaner so you can see it.

But you never know ,
maybe someone that rebuilds these parts might be a judge on a concourse 928 panel,
and recognize the smaller/ larger diameter booster, and gig you for it.

Just tossing out the info about the upgraded part.
Carry on !

Mark Anderson

yes they are the same

Guy

Not to mention the 9 inch booster makes clutch master replacement slightly easier

Thanks for offering this, Mark. Much needed service