Bravo Bellow Kit Fits MerCruiser Bravo I II III & Blackhawk Sterndrives, U-Joint 86840A05 + Exhaust 18654A1 + Shift 74639A2

Three rubber boots, one box — for Compatible with MerCruiser Bravo I / II / III (and Blackhawk in that short mid-90s band). U-joint 86840A05, exhaust 18654A1 (8M0124227 family), shift 74639A2. Rubber only — not a bearing or gasket overhaul.

Why buy all three at once?

Pulling the drive is the hard part. Once it's off, you might as well replace aging rubber while you're in there. All three boots sit in the same heat, salt, and flex — if one's cracked or oily, the other two are usually cooking the same way.

This kit matches the Bravo OEM set (86840A05 + 18654A1 + 74639A2) so you're not guessing parts or pulling the drive again next year because you left old rubber behind.

Alpha Gen II guy? Wrong kit — you want 18BK003 (U-joint is 816431A1, not 86840A05). Only one boot failed? Exhaust is the usual leak → 17B1003. Just swapped the other two? Singles are fine.

What's in the box

Need just one boot? We sell each piece separately.

Component	OEM	Cross-ref	GH single SKU	Qty
U-joint bellow	86840A05	18-2756 / 89140 / 64840P	17B1006	1
Exhaust bellow	18654A1 → 8M0124227	18-2750 / 89100	17B1003	1
Shift cable bellow	74639A2	18-2753-2 / 89080	17B1005	1

 

Which kit is this?

Bravo / Blackhawk three-bellow rubber kit — the set you want when the outdrive's off for transom service on a Bravo-family drive.

Titles sometimes flash 74639Q02 — that's a two-pack catalog number. You get one shift boot (74639A2). Singles: 17B1006 / 17B1003 / 17B1005.

Kit or singles?

Get this kit if:

·       Drive's already off — don't leave two old boots hanging

·       Annual look-see shows two or more boots cracked, soft, or oily

·       Bilge water after a run and you're not sure which boot — plan for all three

·       You want the three Bravo numbers in one shipment

Get a single instead if:

·       Only one boot failed — exhaust is the common one → 17B1003

·       You swapped the other two recently

·       You're just filling one hole from shop stock

Sold separately either way: marine bellows adhesive · expander 22ET001 · sleeve driver 21B1001

Signs you're due for all three

·       Water in the bilge after a run — any of the three boots could be the leak.

·       Drive pulled for another job and the boots look tired — soft, cracked, or shiny with oil.

·       Annual haul-out: more than one boot looking sketchy — swap the set before you splash.

Will it fit my drive?

Read the drive tag / serial — boat year alone lies. Catalog bands:

Brand	Model / Drive	Rated HP	Type	Years	Serial note
MerCruiser	Bravo One / Two / Three	260–430+	Sterndrive	1988+	S/N 0B664190 & Up
MerCruiser	Blackhawk	High-perf band	Sterndrive	1994–1995	S/N 0F186717 & Up

 

Wrong kit? Read before you order

·       NOT for Alpha One Gen II three-bellow kit — that drive boot is 816431A1 → GHMarine 18BK003 / 17B1007.

·       NOT for Alpha Gen I / R / MR rubber kit — ridge U-joint 60932A4 → GHMarine 17B3001 / 17B1004.

·       NOT for full Bravo transom repair with gimbal bearing + gaskets + hoses → GHMarine 18B5001. This box is rubber only.

·       NOT for gasket-only pack 27-94996Q2 — different job.

·       NOT for dual shift pack 74639Q02 as two boots — this kit ships one shift bellow (74639A2).

What ships

·       1 × U-joint bellow (86840A05) with clamps

·       1 × exhaust bellow (18654A1 / 8M0124227 family) with clamps

·       1 × shift cable bellow (74639A2) with clamps

·       Not included: bearing, gasket kit, glue, expander 22ET001, driver 21B1001

Photos should show three rubber boots — skip supplier shots of a full gimbal bearing / gasket overhaul kit.

One boot instead?

·       17B1006 — U-joint Bravo (86840A05)

·       17B1003 — exhaust only (18654A1 / 8M0124227)

·       17B1005 — shift only, one piece (74639A2)

·       Alpha Gen II U-joint → 17B1007 (816431A1), not in this kit

Usually ordered with

·       Bellows expander — 22ET001 (tight exhaust)

·       Sleeve install driver — 21B1001 (U-joint ring)

·       Marine bellows adhesive — sold separately

Install order

1. Pull the whole sterndrive — you're working the transom / bell-housing side, not the engine bay.

2. Shift boot, then U-joint, then exhaust last — exhaust is the tight one; use expander 22ET001.

3. Adhesive both ends; let it tack before final clamp torque.

4. U-joint retainer sleeve → driver 21B1001 per the service steps.

5. Drive back on, muffs, check the bilge for water.

FAQ

What's in the box?

Three rubber boots — U-joint 86840A05, exhaust 18654A1 (8M0124227 family), shift 74639A2. Clamps on the boots. No bearing, no gasket kit, no glue, no tools.

Why buy the kit instead of three singles?

Pulling the drive is the hard part. Once it's off, check all three boots — they live in the same hot, salty mess. One cracked or oily boot usually means the other two aren't far behind. This kit puts the three Bravo numbers in one box so you're not yanking the drive again next season.

Will this fit my Bravo?

Bravo I / II / III from about 1988 up — catalog serials often start at 0B664190 and up. Blackhawk is a short band (about 1994–1995, 0F186717 and up). Read the drive tag. Not Alpha Gen II (816431A1) and not Gen I (60932A4).

Does this include the gimbal bearing?

Nope — rubber only. Want the big overhaul box with bearing and gaskets? That's a different SKU (18B5001 context), not this kit.

I already have an Alpha Gen II — is this the same as 18BK003?

No. Exhaust and shift numbers look familiar, but the U-joint boot is different — Bravo uses 86840A05, Gen II uses 816431A1. Wrong boot = leak. Gen II guys want 18BK003.

Do I need the expander and sleeve driver?

For a proper install, yeah — marine bellows adhesive, expander 22ET001 on the tight exhaust, sleeve driver 21B1001 on the U-joint step. Not in this box.

Please note

Aftermarket replacement kit. Confirm Bravo / Blackhawk drive serial before you order. Not affiliated with engine manufacturers referenced above.