an apparatus is provided for installing a faucet or end body valve assembly on a top side of a deck . the apparatus includes a threaded member engaged with the faucet or end body and extending through the mounting hole to be rotated from above the deck . a wedge nut is threadedly connected to the threaded member to pass through the mounting hole to the underside of the deck . a second member associated with and parallel to the threaded member engages the nut to prevent rotation thereof during rotation of the threaded member whereby the nut will be shifted up or down along the length of the threaded member responsive to the direction of rotation of the threaded member . a retainer member is disposed around the threaded member and includes a plurality of legs which each include a foot portion at an end thereof . upon rotation of the threaded member to raise the nut in the direction of the deck , the wedge nut engages the retainer member and causes the foot portions of each leg to engage the underside of the deck to clamp the faucet or end body to the deck .