Black & Decker Replacement spool cap

Why I needed a new spool cap

A small plastic tab was all it took to sideline my trimmer. On my GrassHog, a cracked spool cap meant the auto-feed stopped working, the line slipped out, and the spool chattered around in the head. I picked up this OEM spool cap as a direct replacement, mounted it on my dual 0.065-inch AFS setup, and put it straight to work on routine edging and cleanup around fences and beds.

What you’re getting

This is a straightforward part: a replacement cap that locks over the trimmer spool and keeps the AFS (Automatic Feed System) behaving as designed. It’s an OEM piece, which matters here because the tolerances on the bayonet tabs and the profile that captures the spool lip are what determine whether the auto-feed works consistently. The cap is light—about a tenth of a pound—and feels like a rigid, glass-filled plastic rather than a soft, brittle resin. You don’t get extras in the bag; it’s the cap only. The internal spring that helps tension the spool stays with the trimmer head, and the line/spool are separate consumables.

The cap is designed for dual 0.065-inch line heads and is compatible with GrassHog models including GH700, GH710, GH750, and the 74547 variant. The part number is RC-065-P. If your trimmer uses a single-line head, a thicker line (like 0.080), or a different cap style, this isn’t the right match.

Fit and compatibility

Fit is everything with these parts. On the GH710 and GH750 I tried, the cap seated neatly without play and locked with an audible click. There’s just enough compression on the spool to prevent rattle while still allowing the AFS to advance line when the motor cycles. The cap’s tabs engage cleanly and don’t require excessive force to close—if you’re straining, you’re probably misaligned or on the wrong model.

My advice before you buy:
- Confirm your exact model number (it’s usually etched on the motor housing or near the handle).
- Verify that your head uses dual 0.065-inch line and an AFS spool.
- Match the part number (RC-065-P) to your manual’s exploded parts diagram.

It’s easy to assume these caps are universal. They’re not. Small differences in tab geometry and inner lip height will cause misfeeds or a cap that simply won’t lock.

Installation and setup

Swapping the cap takes a minute:
1. Unplug or remove the battery.
2. Turn the trimmer upside down and clean any packed grass around the head.
3. Press in the old cap’s tabs and pull it off.
4. Confirm the spool is seated flat with the line exiting through the eyelets.
5. Align the new cap’s tabs to the slots and press until it clicks.

Two tips that help:
- If the cap won’t click with firm thumb pressure, don’t force it—realign and try again.
- Make sure the line isn’t trapped under the cap’s lip; feed it out the eyelets before closing.

Performance in use

With the new cap on, my AFS immediately returned to normal. The line advanced predictably, keeping a consistent cut length without the stuttering I saw with the cracked cap. On a typical 30–40 minute trim of edging stones, chain-link fence, and lawn borders, the cap stayed put, the spool didn’t chatter, and I didn’t have to pop the head open mid-job.

Auto-feed systems can be finicky if anything is off—line wound too tight, debris under the spool, or a cap that doesn’t hold the spool at the right height. After installing this cap, I intentionally ran different line brands to see if the cap masked any minor inconsistencies. It didn’t correct poor winding (nothing will), but it also didn’t introduce any new issues. That’s what I want from an OEM cover: neutrality and reliable tolerances.

Build quality and durability

The latch tabs are the usual failure points on caps like this. After several weeks of use and a few intentional on-off cycles to test fatigue, the tabs still feel crisp. I dropped the cap on a concrete garage floor and didn’t see any cracking or whitening at stress points. That said, UV exposure and heat cycles will eventually age any plastic—if you store your trimmer in full sun, every cap becomes consumable. Keep it in a shed or garage and expect a long service life.

One note on technique: you don’t need to squeeze the tabs like a clamp to remove it. Press at the molded grip areas and the cap releases cleanly. Forcing it off at an angle is the fastest way to fatigue or snap a tab.

Maintenance and usability notes

• Keep the head cavity clean. Caked mud and grass under the spool can lift it just enough to interfere with feeding.
• Replace your line when it’s near the arbor; low line can cause rapid tap-advance cycles and hammer the cap.
• If your auto-feed still misbehaves after installing a new cap, check the spool spring and eyelets for damage. The cap isn’t a cure-all for every feed issue, but it’s foundational.

Value

This is a modest, inexpensive part with an outsized effect on whether your trimmer feels “right.” Replacing a broken cap restores function without replacing the entire head or the tool. The 2-year limited warranty is a nice backstop for a small item. You can find aftermarket options for a few dollars less, but in my experience, non-OEM caps are hit-or-miss on tab fit and inner height. Given the low price difference and the headache of returns, I lean OEM for this specific piece.

Where it falls short

• It’s not universal. If your trimmer isn’t one of the supported GrassHog models or if it uses a different line size, this cap won’t fit.
• Packaging is minimalist—cap only. If your trimmer’s internal spring or spool is damaged, you’ll need those parts separately.
• Like all plastic caps, the tabs will eventually age. That’s more a reality of the category than a flaw with this one.

Who it’s for

• Owners of compatible GrassHog trimmers (GH700, GH710, GH750, 74547) who need to restore AFS performance.
• DIYers who prefer predictable, OEM fitment over experimenting with aftermarket caps.
• Anyone dealing with a cracked or missing cap, spool rattle, or inconsistent line advance.

Quick pros and cons

Pros:
- Precise OEM fit on compatible dual 0.065-inch AFS heads
- Restores reliable auto-feed and eliminates spool chatter
- Light, rigid construction with tabs that latch securely
- Inexpensive fix with a 2-year limited warranty

Cons:
- Not compatible with non-listed models or different line sizes
- Cap only; doesn’t solve issues caused by a worn spring or damaged spool
- Plastic tabs, while solid, are still a long-term wear item

The bottom line

The spool cap is a simple part that either works perfectly or becomes the source of constant frustration. On the compatible GrassHog models I tested, this one works the way it should—secure fit, proper spool tension, and consistent auto-feed with dual 0.065-inch line. Installation is quick, the material feels up to the abuse of routine trimming, and I haven’t seen the tab fatigue that plagues cheaper caps.

Recommendation: I recommend this cap for anyone with a compatible dual 0.065-inch GrassHog trimmer who needs a reliable OEM replacement. It restores the tool’s intended behavior at minimal cost, and the correct fit avoids the misfeed headaches that come with look-alike alternatives. Verify your model number and line size before purchasing, and it’s an easy yes.