Best faucet cartridge replacements

Match the model and retaining hardware before ordering.

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Quick answer

Choose Delta RP50587 when your parts drawing lists it; some two-handle Delta models specify RP25513. Pfister 974-0740 matches Pasadena F-529-7PD. Check your model’s parts drawing first.

Delta RP50587$45.03 at AmazonPrice as of Oct 24, 2026, 5:30 AM EDT

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For confirmed Delta DST valves

Delta RP50587

$45.03 at Amazon

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Price as of Oct 24, 2026, 5:30 AM EDT

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For matching two-handle Delta faucets

Delta RP25513

$16.69 at Amazon

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Price as of Oct 24, 2026, 5:30 AM EDT

Read the fit details

For confirmed Pasadena F-529-7PD fit

Pfister 974-0740

$14.13 at Amazon

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Price as of Oct 24, 2026, 5:30 AM EDT

Read the fit details

Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product.

Delta RP50587 fits DIAMOND Seal Technology kitchen and lavatory models that use the 36 mm Delta-motion cartridge. That full description matters. “Delta single handle” is a broader category than the application in Delta’s instruction insert, so the faucet’s model record must confirm the part.

The useful installation clues are at the bottom: a seal and guide pins that align with openings in the faucet body. Compare those features with the maker’s diagram. A similar stem above the handle opening does not establish that the lower locating features match your valve.

The retainer is a bonnet nut. Delta’s insert requires wrench tightening and warns of water damage when the bonnet is inadequately secured. Use the applicable instructions rather than a tightening rule borrowed from a Moen retainer. Keep the water supplies off while removing or assembling the cartridge.

For repair planning, Delta says the cartridge has no repairable internal parts. A generic seat-resurfacing instruction therefore does not describe service inside RP50587. If another guide tells you to dismantle the cartridge itself, check that it is addressing the same part and the same faucet system.

RP50587 also has an optional handle limit stop. Delta warns that it does not compensate for incoming pressure changes or sudden water-temperature changes. Do not treat that stop as a guarantee against scalding, and ask a plumber to resolve unsafe or unpredictable hot-water delivery.

Keep the complete model match ahead of the listing’s size label. Words such as “Small” do not replace the specified 36 mm application or the locating-pin drawing. Record the cartridge number beside the faucet model so a later repair does not start from the listing title alone.

For a two-handle Delta sink, use that model’s stem and seal diagram instead of assuming this DST cartridge applies. RP25513 is a different repair subject. A shared maker name is useful for finding documents, but it does not make those two assemblies interchangeable in an unidentified faucet.

Delta RP25513 is a two-handle stem assembly. The Cassidy 3595LF parts drawing identifies it separately from the bonnet nuts and the seats and springs. That exploded view is the right starting point for deciding what is being replaced and what remains inside the faucet.

A persistent spout drip after stem replacement does not prove that RP25513 is defective. The stem assembly and the faucet’s sealing parts have different entries in the exploded view. Check the model’s troubleshooting instructions for the observed leak rather than assuming the stem alone accounts for every possible fault.

The quarter-turn stop is part of the RP25513 assembly’s identity. Delta’s support answer distinguishes this stem from a similar version without that stop. That relationship does not prove that an Amazon package includes every separate seal elsewhere in the faucet’s parts drawing. Compare the exact branded assembly with the model record.

Keep the old stop arrangement in the repair photograph. The handle’s closing action depends on the correct assembly, and the model’s instructions are more useful than a generic instruction to rotate the cartridge. If the stop position is uncertain, ask Delta to confirm it before the water supplies are reopened.

The 3595LF diagram lists the seats and springs separately even though a marketplace title may describe a large repair kit. Separate the genuine stem’s identity from the contents of an unrelated bundle. A compatible-brand kit with several recognizable RP numbers is not automatically a genuine Delta package.

Use the symptom record alongside the parts diagram. A leak at the handle and a drip from the spout may require different checks within the same two-handle assembly. The new stem does not establish the condition of the separate seat, spring or other seals that the drawing identifies.

This is a model-specific stem route, not a universal bathroom faucet cartridge. If the confirmed faucet uses a DST cartridge or a different stem number, leave RP25513 out of that repair plan. Resolve the model before interpreting the shape of a loose brass part as proof of compatibility.

Pfister’s Pasadena F-529-7PD maintenance drawing identifies cartridge 974-074 beneath a separate retainer. That pairing gives you a specific faucet, a cartridge and the hardware that holds it. It is stronger evidence than choosing a part simply because its title mentions Pfister or a familiar collection name.

The SS-974-074 specification calls this a 25 mm ceramic-disc cartridge. The diameter describes the identified part; it is not a universal fit rule for every 25 mm valve. Keep the faucet-model drawing beside the specification so the size never becomes the only compatibility check.

You may encounter 974-0740 in a replacement listing while the Pasadena diagram prints 974-074. Pfister’s 974-0740 support record links to specification SS-974-074. That connects these two number formats. Still use the model’s parts drawing; an added suffix in an unrelated listing is not evidence of the same application.

Check the retainer independently. The F-529-7PD cartridge drawing does not establish that the installed retainer is undamaged or that an Amazon package includes one. Record what the faucet requires and compare that list with the actual package contents before the faucet is taken out of service.

Pfister’s maintenance guide requires the water supplies to be closed and pressure relieved before faucet work. If flow continues after isolation, leave the cartridge assembly intact and have a plumber address the shutoff problem. The fit check does not remove that basic safety requirement.

Finish care matters while the handle parts are off. The Pasadena guide specifies a soft damp cloth for decorative finishes and excludes acids, solvents and abrasive cleaners. A blanket vinegar-soak recommendation would conflict with that care instruction. Do not introduce chemical cleaning as a substitute for the proper service procedure.

Keep the Pasadena model as the boundary for this example. Another Pfister faucet may need another cartridge even if its handle looks similar. Use its own parts drawing and retainer details before carrying the 974-074 reference into a different kitchen or bathroom repair.

Part	Best for	Confirmed application	Hardware to check	Pro and limit	Amazon
Delta RP50587	For confirmed Delta DST valves	DST kitchen/lavatory models specifying RP50587	Bottom seal, guide pins and bonnet nut	Documented 36 mm Delta-motion application Does not replace a two-handle stem	Amazon
Delta RP25513	For matching two-handle Delta faucets	Two-handle models specifying RP25513; 3595LF example	Stem/stop assembly; separate seats and springs	Documented Cassidy 3595LF application Seats and springs are separate from the stem	Amazon
Pfister 974-0740	For confirmed Pasadena F-529-7PD fit	Confirmed Pasadena F-529-7PD; other models need their own drawing	974-074 cartridge beneath the separate retainer	25 mm ceramic-disc specification 25 mm alone does not establish fit	Amazon

For a kitchen faucet replacement cartridge, the brand name starts the search but does not finish it. A Moen logo does not distinguish a clip-retained cartridge from a nut-retained service kit. A Delta logo does not distinguish a DST cartridge from a two-handle stem assembly. Find the model’s parts drawing before comparing offers.

Bathroom faucet cartridge replacement needs the same care. Moen’s bathroom chart separates newer service-kit families from older cartridge designs. A short list of familiar numbers can miss the part already installed in your sink. Use the model record and the retaining hardware together, especially when the faucet’s age is uncertain.

Keep a simple record before opening an Amazon listing: faucet model, cartridge number and retainer number when the drawing gives one. Put the maker’s diagram beside the listing. A title that mentions your brand or several similar part numbers is weaker evidence than an exact match to the faucet’s own parts list.

For an unidentified sink faucet, keep the evidence you already have instead of filling the gaps with a guess. A photograph of the whole faucet preserves its handle and spout arrangement. A second photograph can show the model marking or the existing paperwork. Ask the maker to confirm the part when those clues do not settle it.

Read across one complete row. The Pasadena F-529-7PD drawing identifies the cartridge and retainer separately, while Moen’s Duralast chart distinguishes service kits by their nuts.

A stop condition is our conservative selection rule. It is not a claim that every faucet in the row has the same fault or needs a complete cartridge.

An identification chart needs an exit for parts it does not cover. Moen’s newer bathroom families include similar-looking retaining nuts on noninterchangeable service kits. An older clip-versus-nut identification shortcut cannot settle every newer faucet. Keep the model unresolved when the identification chart points to a different family.

Keep kitchen and bathroom evidence separate when the manufacturer does. The kitchen chart includes several distinct service kits in its Duralast group. The bathroom chart lists its own groups and newer families. A kit number from one chart is a prompt to check the exact model, not permission to expand the other chart’s coverage.

For a Kohler, Grohe, American Standard or unlisted faucet, the absence of a matching row is a reason to use that maker’s model lookup. Do not translate one of the Moen, Delta or Pfister examples by matching stem color. Keep the exact service part unresolved until its own documentation confirms it.

For a tub or shower control, move to the shower cartridge replacement guide. A sink cartridge number does not establish pressure-balance or thermostatic valve compatibility. Shower identification also involves temperature-control requirements that should not be inferred from a kitchen faucet repair.

Write down whether the problem is a spout drip with the handle closed, water near the handle, or water below the sink. Those are locations to investigate, not interchangeable diagnoses. The Delta RP25513 example shows why the distinction matters: the stem and separate seals have different entries in the parts drawing.

A wet cabinet does not prove the cartridge is the source. Record the first visible wet location and use the faucet’s troubleshooting sheet to distinguish the supply connections from the valve assembly. For the broader diagnosis, start with how to fix a dripping faucet before selecting a replacement cartridge.

For restricted flow, Moen warns that debris left in the valve body can obstruct water or damage a new cartridge. That is a reason to use its cleaning and controlled-flushing procedure, not evidence that every slow faucet has the same cause. Keep an aerator complaint separate until the model’s troubleshooting checks connect it to the valve.

An electronic or touchless faucet may also have controls outside the mechanical cartridge assembly. Use its exact service instructions for those faults. Do not disconnect wiring or improvise an electrical repair from a mechanical cartridge chart. If the symptom cannot be separated safely, have a plumber handle the diagnosis.

Do the model lookup while the faucet is still assembled whenever possible. Moen’s identification guides use handle operation and retaining hardware together, but handle removal must follow the applicable faucet instructions. A photographed cartridge is useful evidence only after the supplies have been isolated and the correct retaining parts have been released.

Before any handle, bonnet or cartridge removal, close both water supplies and open the faucet to confirm flow stops, following Moen’s shutoff instructions. Pfister likewise requires pressure relief before faucet work. Residual water is different from continuing flow. If you cannot confirm isolation, stop and have a plumber address it.

1. 1
   Save the model evidence

   Record the faucet model and the matching parts drawing. Keep the existing handle arrangement in a photograph.

2. 2
   Verify water isolation

   Follow the maker’s supply-shutoff and pressure-relief instructions. Do not loosen a retainer if water continues to flow.

3. 3
   Compare the retaining hardware

   With the maker’s specified handle parts removed safely, compare the clip, nut or bonnet with the illustration. Photograph the arrangement.

4. 4
   Resolve a mismatch before extraction

   An unexpected nut, missing clip or damaged valve body is a stop point. Ask the maker to identify the assembly or have a plumber take over.

Keep small pieces organized by assembly. On a two-handle faucet, the cartridge nut and stem extension have different positions in the assembly drawing. On a Delta RP25513 repair, the stop and seats/springs are separately identified. A loose group of parts without an orientation record makes it harder to tell what was damaged, omitted or incorrectly reassembled.

Do not use a seized cartridge as a reason to pry against the faucet body or invent a drilling method. The model’s cartridge instructions describe its ordinary removal sequence. If the shell breaks, the body moves or that method is unsuccessful, leave the supplies off and have a plumber assess extraction.

For the service sequence, follow the exact maker instructions alongside how to replace a faucet cartridge. RP50587 uses guide pins and a bonnet, while the F-529-7PD drawing identifies a different cartridge-and-retainer assembly. Keep supplies off and pressure relieved during disassembly; a matching part number does not make the retaining steps identical.

For a retaining clip that will not seat, check cartridge seating and tab alignment in the model’s instructions. Bending the clip to make it enter changes the safety question instead of resolving the fit. Keep the faucet isolated and get the alignment or damaged hardware checked before restoring water.

For a replacement that feels wrong at the handle, return to the assembly drawing. The stem extension, cartridge location and retaining components must agree with that model. Do not correct a mechanical mismatch by forcing the handle down or tightening unrelated parts beyond the maker’s procedure.

After a correctly retained assembly is complete, use the model’s startup checks and observe the faucet and cabinet as supplies are restored. If water appears at a retainer or connection, shut the supplies again. A dry-looking spout alone does not establish that the whole assembly is leak-free.

Hot/cold checks also depend on the cartridge. Some Moen instructions address reversed water by changing stem position; other cartridges have keyed ribs and grooves. Do not rotate an unfamiliar cartridge body because a different faucet’s repair video used that method.

Moen’s flushing article warns that water can leave an open valve body with considerable force. Its deckmount procedure controls that discharge with a bowl and coordinated supply operation. Read the complete procedure before attempting it. If the discharge cannot be controlled safely, leave the supplies off and use a plumber.

Avoid adding a cleaning chemical to solve an assembly problem. Pfister’s Pasadena care sheet restricts decorative-finish cleaning to a soft damp cloth. That instruction conflicts with casual advice to soak every faucet component in vinegar. Follow the exact part’s care instructions rather than treating all finishes and seals alike.

Ask the maker about the confirmed faucet and its symptom before assuming the cartridge must be purchased. Moen’s warranty-parts FAQ asks for the model, proof of purchase, faucet age and repair history. Those questions support a case-specific decision, not a promise that every caller receives a free replacement.

For a Pfister Pasadena example, use that faucet’s own warranty and care guide. Warranty terms and eligibility are different evidence from cartridge fit. Keep the proof of purchase and model information together, and ask which part resolves the documented fault. Do not assume a replacement-part decision includes installation labor.

Separate the identification question from the fulfillment question. First ask which exact cartridge and retaining hardware the faucet needs. Then ask whether the maker’s warranty applies to that repair. A clear part number remains useful even if support needs more ownership information or reaches a different warranty decision.

A previously replaced cartridge can complicate the evidence record. Tell support what changed and whether the current symptom began before or after that work. Keep the old and replacement part numbers separate so the last installed cartridge is not silently treated as proof of what the faucet originally required.

Sources

• Moen Faucet Cartridges: Kitchen, article 82667, single- and two-handle identification tables, checked October 20, 2026.
• Moen Faucet Cartridges: Bathroom, article 82666, Duralast, newer single-handle and two-handle identification tables, checked October 20, 2026.
• Moen kitchen cartridge service instructions, article 82581, retaining-clip FAQ.
• Moen Muirfield CA84000SP, Rev. 3/09, page 1; Moen 8798 SPC11479SP, Rev. 03/24, page 1; M•Dura 9419F12SP, 1/16, page 1.
• Delta RP50587 instruction insert, 64211 Rev. A, page 1, application, seal, pins, bonnet and limit-stop warning.
• Delta Cassidy 3595LF parts drawing, DPD-L-3595LF-LHP, September 2, 2015, page 1.
• Delta RP25513 official support page, manufacturer answers about separate seats/springs and the quarter-turn stop, checked October 20, 2026.
• Pfister Pasadena F-529-7PD Maintenance & Care Guide, 40436-0700, April 9, 2021, parts diagram page 2 and safety/finish care page 3.
• Pfister 25 mm Cartridge Specifications, SS-974-074, July 23, 2018, page 1; Pfister 974-0740 support record, model field and linked specification.
• Moen How To Turn Off The Water Supply To The Faucet; Valve Body Cleaning and Flushing; warranty-parts questions FAQ, checked October 20, 2026.
• Amazon Creators API offer records, Oct 22, 2026, 8:12 AM EDT: B00263BYSQ and B001D0N63Y (brand Delta), B002J3SH8I (brand Pfister); all new and in stock. Availability can change.