Brake booster to suit 01 V70XC

Looking for a brake booster for a 2001 V70XC, I've been told it's the single sensor type.

Are they rebuildable? Is your one failing?

Sandwood trading used to keep them in stock 03 9898 0314

I'm guessing yours is hissing under the dash?

Big job to replace though...

Thanks for the replies. Not sure if it's rebuildable, also not sure on the failure mode as it's for a mate who is a mechanic.