GP77886 is Kohler's mixer cap for older style Coralais single-handle tub and shower valves. Its stem is square and brass, which Kohler's identification tool reads as a K-15700 or K-15701 valve. The 500520 pressure balancing unit behind it is a separate part.
The FourHome replacement for Kohler GP77886: mixer cap, square brass stem, retaining plate. Bench photo.
Specifications
OEM numbers
GP77886 (cap); 77886 on Kohler's Coralais parts sheets
Kohler's name
Mixer cap for older style Coralais (brass stem)
Type
Mixer cap, single-handle pressure-balancing tub and shower valve
Valves
Kohler Coralais K-15700 or K-15701 (K-15701-K, K-15701-KS)
Stem
Square, brass, no adaptor
Unit behind the cap
Kohler 500520 pressure balancing unit, a separate part
Kohler's mixer cap for older style Coralais trim, with a square brass stem. The cap only, no pressure balancing unit.
77886
Kohler
The same cap as numbered on Kohler's Coralais service parts sheets, drawn in front of the 500520 pressure balancing unit.
77885
Kohler
Kohler's Coralais-only repair kit: GP77886 plus the GP500520 unit. The cap alone covers the cap half of that kit.
Where it goes
Kohler's valve identification tool sends a square brass stem with no adaptor to the K-15700 or K-15701 Coralais valve, and its Mixer Cap button for those valves opens Kohler's GP77886 page.
Kohler's K-15701 specification sheet calls that valve the Coralais Rite-Temp pressure-balancing valve, sold as K-15701-K without screwdriver stops and K-15701-KS with them.
Kohler's 2011 service parts catalog prints GP77886 (brass stem) and GP71969 (plastic stem) on one row for Coralais bath and shower faucets, including K-15101 to K-15108, K-15110 to K-15112 and K-15120 to K-15129. The row does not split the two caps by model; the stem does.
Confirm it is your part
Back of the cap. Bench photo.
Pull the trim. If an adaptor sits on the stem, Kohler says to take out its screw if there is one and slide it off. Judge the bare stem.
The stem is square. A round splined stem belongs to the K-304, K-305 or K-11748 family, which takes the GP77759 cap or the GP876851 kit.
The square stem is brass colored. Black or gray sends Kohler's tool to the K-15877 and the GP71969 cap. Silver means K-15153 or K-15155, which take a cartridge, not a mixer cap.
Look along the stem for the limit stop and an O-ring in a groove. Kohler's kit sheet draws an upper and a lower limit stop; its parts sheets list 79489 Stop Limit.
Note the collar. Kohler's kit sheet shows this cap with either a flat collar or a flanged collar, and says the flanged collar is kept.
Behind the cap, Kohler's Coralais sheets show the 500520 pressure balancing unit as its own piece in the brass body. If the unit has failed, the cap alone does not replace it.
Look-alikes
Kohler GP77759 cap, or the GP876851 and GP76851 cap and unit kit
Why it gets confusedKohler mixer caps for the same layout, sitting over the same pressure balancing unit number.
How to tellRound splined stem, which catalogs list at 19 points. Kohler's tool sends a round stem under a black plastic cap with two screws to K-304, K-305 or K-11748. GP77886 has a square brass stem.
Kohler GP71969, square plastic stem
Why it gets confusedAnother square-stem Coralais cap, printed on the same row of Kohler's 2011 catalog.
How to tellThe stem is plastic, black or gray, not brass. Kohler's tool sends that stem to the K-15877 valve. Kohler's brochure says GP71969 is also used on Sterling shower units.
Kohler 77885 complete repair kit, Coralais only
Why it gets confusedSame square brass stem cap, and Kohler's kit sheet covers 77885 and 77886 together.
How to tell77885 adds the GP500520 unit. GP77886 is the cap alone. The cap looks the same either way; the box contents differ.
Kohler GP500520 or GP800820 pressure balancing unit
Why it gets confusedIt sits right behind this cap and comes out next to it.
How to tellNo stem and no collar. Kohler numbers it separately, 500520 Press. Bal. Unit on the Coralais sheet, and its brochure says GP800820 replaces GP500520.
Numbers other makers and sellers list against this part. The notes say how far each one goes.
Maker
Number
Note
Everbilt
71542
square broach
Grainger
493L22
genuine GP77886
Not printed on this page
Where the sources disagree, the figure is left off until it is settled.
Overall length. The index, Everbilt and the FourHome listing do not give one agreed figure with stated reference points, so none is printed.
Cap diameter. Retailer titles and the listing give different widths, so none is printed.
Size of the square on the stem. No public source gives it.
Kissler and other store-brand numbers. No page naming both numbers was opened.
K-15700 model suffixes. Kohler's tool names the K-15700, but no Kohler document opened lists its versions.
Field notes
Kohler Assist gives one pressure balancing unit procedure for the K-304 and the K-15701, and a separate one for the Coralais K-15877, which uses thick washers and a grey adapter plate.
FourHome replacement
The FourHome replacement for Kohler GP77886 ships as the mixer cap with its square brass stem and cap O-ring fitted, a retaining plate, two cap screws and a grease packet, without the pressure balancing unit.
FourHome replacement
Replacement for Kohler GP77886 Mixer Cap
For
older Coralais shower valves
Out of stock on Amazon when this page was built (October 13, 2026). The button comes back when it is restocked.
FourHome publishes this site. The button goes to our own listing on Amazon.
Catalogs disagree now and then, and makers revise parts without changing the number. Compare the old part before buying. Identify by measurement lists every indexed part near a given length and spline count.
