Pay in installments of $8.00 with
,
and
Shipping Estimate
USA
- USA
- CAN
- USA
- CAN
Ships within 48 hours · Estimated delivery Aug 12 - Aug 17
Promo Codes Available:
For Your Every Summer RSVP, with Code: SUMMER15
Description
86840A05 U-Joint Bellow for Mercruiser Bravo I II III Blackhawk | JLM MarineU Joint Bellow for Mercruiser Bravo I II III Blackhawk OEM 86840A05 Replacement This U Joint bellow is designed as a direct replacement for Mercruiser Bravo I, II, III, and Blackhawk sterndrive models from 1988 and up. Engineered to protect the universal joint from water intrusion and contamination, this bellow ensures reliable performance and extends the service life of your engine bell housing assembly. Replaces OEM part numbers 86840A3, 86840A05,
U-Joint Bellow for Mercruiser Bravo I II III Blackhawk – OEM 86840A05 Replacement
This U-Joint bellow is designed as a direct replacement for Mercruiser Bravo I, II, III, and Blackhawk sterndrive models from 1988 and up. Engineered to protect the universal joint from water intrusion and contamination, this bellow ensures reliable performance and extends the service life of your engine bell housing assembly.
Replaces OEM part numbers 86840A3, 86840A05, and 8M0062406, as well as aftermarket equivalents including Sierra 18-2756 and Mallory 89140. This kit includes all necessary installation components for a complete repair.
- Complete kit with bellow, clamps, clips, and sleeve
- Features bellow with ridge for improved durability
- Fits Mercruiser Bravo and Blackhawk sterndrive systems
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| Brand | Part Number |
|---|---|
| Mercruiser (OEM) | 86840A3 |
| Mercruiser (OEM) | 86840A05 |
| Mercruiser (OEM) | 8M0062406 |
| Sierra | 18-2756 |
| Mallory | 89140 |
Compatible Engine Models
Confirm your engine model/year in the table below.
| Brand | Model | Years | Serial No. Range |
|---|---|---|---|
| Mercruiser | Bravo I / II / III | 1988 & Up | 0B664190 & Up |
| Mercruiser | Blackhawk | 1994-1995 | 0F186717 & Up |
Technical Specifications
| Specification | Value |
|---|---|
| OEM Number | 86840A05 |
| Application | U-Joint Bellow for Engine Bell Housing |
| Bellow Type | With Ridge |
| Compatible Systems | Mercruiser Bravo I, II, III & Blackhawk |
Package Contents
This complete kit includes:
- 1 × U-Joint Bellow (with ridge)
- 1 × Clamps
- 1 × Clips
- 1 × Sleeve
Installation Guide
- Preparation: Disconnect the battery and raise the sterndrive to access the gimbal housing area. Remove the drive unit according to your service manual.
- Remove Old Bellow: Cut off the old U-joint bellow and remove the retaining clamps and clips from the gimbal housing and bell housing.
- Clean Surfaces: Thoroughly clean the bell housing and gimbal housing surfaces where the new bellow will seat. Remove all debris, corrosion, and old adhesive.
- Install Sleeve: Slide the provided sleeve onto the U-joint shaft at the correct position as indicated in your service manual.
- Position New Bellow: Carefully slide the new U-joint bellow over the shaft and align it with the bell housing groove, ensuring the ridge faces the correct direction.
- Secure with Clamps: Install the provided clamps at both ends of the bellow and tighten evenly to the recommended torque specification. Attach clips to secure the bellow in place.
- Inspect Installation: Verify that the bellow is seated properly without twists or kinks and that all clamps are secure.
- Reassemble Drive: Reinstall the sterndrive unit following your service manual procedures. Reconnect the battery and test for leaks by running the engine in a test tank or on the water.
Troubleshooting & FAQ
Q: How do I confirm this U-joint bellow fits my Mercruiser engine?
A: Check the compatibility table above for your model and year, then verify your serial number falls within the specified range (0B664190 & Up for Bravo models, 0F186717 & Up for Blackhawk). Cross-reference your current bellow's OEM number with the part numbers listed.
Q: How often should I replace the U-joint bellow?
A: Inspect the U-joint bellow annually or every 100 hours of operation for cracks, tears, or deterioration. Replace immediately if you notice any damage, as a failed bellow can allow water into the gimbal bearing and cause serious damage.
Q: What are the signs that my U-joint bellow is failing?
A: Common symptoms include visible cracks or splits in the rubber, water in the bilge near the transom assembly, corrosion on the U-joint or gimbal bearing, and excessive play or noise during engine operation.
Q: Does this kit include all the parts I need for installation?
A: Yes, this kit includes the U-joint bellow with ridge, clamps, clips, and sleeve—everything needed for a complete installation. You may want to apply marine grease to the U-joint during reassembly (sold separately).
Q: What's the difference between OEM and aftermarket U-joint bellows?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.
Important Notes
- Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
- This product is an aftermarket replacement part and is not an OEM component.
- Professional installation is recommended to ensure safety and optimal performance.
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- Standard Shipping : 3-10 business days
- If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
- We offer a 30-day return/exchange service after receiving.
- Final sale items are not eligible for returns or exchanges.
- To process your return/exchange, please contact us at [email protected]
- Please click here for more details>>> Return & Exchange Policy
4.4 ★★★★★
Based on 15 reviews
Sort
Product Reviews
★★★★★ 4
Easy to assemble, does the job, material is shiny nylon and shows creases, minor defects, sloppy
Size: 3 Panel 12FT W, Size: 3 Panel 12FT W
The Siebwin room divider is a good idea, and for the price, it mostly delivers on the intended functionality. I ordered the 12 foot, 3-panel version mainly to hide an unfinished basement storage area that had become an eyesore. It works well for that purpose and gives the space a cleaner appearance without spending the kind of money that more decorative dividers or custom partitions cost. If you need something temporary, portable, or mainly functional, this is a viable option.
There are a few limitations that became obvious during setup and use. The first thing I noticed was that the weld quality on some of the metal poles is fairly sloppy. Once the cover is installed, you do not really see it, but up close, it does not look especially refined or professional. The blackout material also is not a matte canvas style fabric as I expected. It has more of a shiny nylon appearance, and the creases are fairly visible. Being that it’s more of a nylon, I’d be hesitant to try steaming it to remove the creases. However, the creases do not matter if you are using it in a basement, dorm, or shared room, but for photography, video work, or a professional office setting, the appearance could be disappointing. The fabric is thick enough, though. It blocks visibility well enough, but strong light behind it still shows through to some extent, nothing deal-breaking. Also, my fabric appeared to be slightly defective. The hook and loop strip on one of the bottom sections was off-center and couldn't be totally attached because it was lined up with one of the legs. I originally hoped to use this as a video backdrop, but I will probably end up replacing the fabric with a proper green screen or canvas material while continuing to use the frame itself. For now, it does a good job of covering my basement junk.
Assembly was actually easier than I expected and took roughly 15 to 20 minutes. The longer vertical poles are tethered together similarly to tent poles, which made setup straightforward and fairly intuitive. The shorter horizontal pieces slide and snap together to the top and bottom of the vertical assembly. After each section is assembled, the divider panels connect together with metal plates and two knurled screws (at the top and bottom), so no tools are really required. A few screws were difficult to start because paint had gotten into the threads, but once they caught, they tightened down normally. The feet install with similar knurled fasteners and help keep the divider reasonably stable. One thing to watch for during setup is the fabric orientation. There is one arrow indicator in the middle of the fabric to indicate up. However, if you need another indicator, the smaller hook and loop strip goes on the bottom while the longer strip goes on top. I realized mine was upside down right before finishing and had to redo it. I wasn't difficult to redo, despite the defect in mine.
The overall design is practical and easy to move around. I do like that the panels can fold and bend into different shapes depending on the space. The widened feet help stability, although when trying to stretch the fabric tight, I noticed the poles sometimes wanted to overlap slightly at the joints. Tightening everything helped somewhat, but it still happened occasionally. The divider feels adequate for normal indoor use, though I would not expect premium durability or luxury-level fit and finish at this price point. The entire device can also be easily disabled and stored in a tote if you need it completely out of the way. It comes with assembly instructions, but even if you didn’t have them, it’s easy to build without them (save a mistake or two).
In terms of value, I think the Siebwin divider mostly matches its price. Around $100 gets you a large freestanding partition with decent usability and easy assembly, but there are compromises in materials, appearance, and refinement. The defects are also off-putting, but hopefully you won't have them. Higher-end room dividers can easily cost two or three times more, so some of the tradeoffs are expected. I also noticed cheaper alternatives online, but based on the quality here, I suspect those would probably have even more issues. For practical home use, temporary privacy, hiding storage areas, or separating shared spaces, this is a good option as long as expectations stay realistic.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 18, 2026
★★★★★ 3
Works well but takes up more space than expected
Size: 2 Panel 8FT W, Size: 2 Panel 8FT W
This room divider does the job for creating a little extra privacy and was easy enough to set up. The panels feel decent quality and the wider feet help keep it more stable than some cheaper screens I’ve tried. My only issue is that it takes up a bit more room than I expected, especially with the feet sticking out. It’s still portable and folds away nicely, but definitely measure your space first. Overall it works well for separating a room or blocking off an area temporarily. i wish it came in other colors
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 26, 2026
★★★★★ 5
Nice divider, serves it's purpose well!
Size: 3 Panel 12FT W
This room divider worked out very well for what I needed. I wanted a simple way to create a little more privacy and separation in a larger room without doing anything permanent, and this divider was an easy solution. The panels provide good coverage, and the black color gives it a clean, modern appearance that blends in nicely with different décor styles.
Assembly was fairly straightforward, and once set up, the wider feet helped keep the divider stable on the floor. I was especially happy with how flexible the panels are to arrange. You can keep it mostly straight, angle it around furniture, or create a more enclosed private space depending on the layout you need.
The material allows light to filter through slightly while still offering a noticeable sense of privacy. I’ve used it for separating a workspace area, but it would also work well in bedrooms, apartments, dorms, studios, or shared living spaces. Another plus is that it can be folded and moved without too much effort when you want to change the setup.
Overall, this divider delivers a good balance of functionality, portability, and appearance. It’s a practical option for anyone needing temporary room separation without installing permanent walls or curtains.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 26, 2026
★★★★★ 5
Perfect for Adding Privacy to a Piano Studio
Size: 2 Panel 8FT W, Size: 2 Panel 8FT W
I Ordered the 2 Panel version which is way too big for my needs... that's on me. So keep in mind that the picture shows a fabric made for two panels only being used on one and hence it is not pulled tight; it would pull tight and not be so wrinkly if it was set up properly as two panels. The metal pools that make up the panels seem to be well made, stable, and of good quality. They were very easy to put together and they stand up tall with plenty of height. The appearance of it with the fabric on it isn't as elegant as it could be, but it still looks good enough. The material is plenty solid, not allowing light through it, and thereby making a solid barrier. I am using it to block the view out the studio door when a student is sitting at the piano to avoid distractions from the hallway. It will allow a student to enter the studio with our distracting the student who is at the piano.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 18, 2026
★★★★★ 5
Room Divider That Gives Instant “This Is a Separate Space Now” Energy
Size: 3 Panel 12FT W
The Siebwin 3 Panel Folding Privacy Screen is surprisingly effective at changing the feel of a room without requiring construction, commitment, or somebody yelling about load bearing walls. The 12 foot width gives a substantial amount of coverage, making it useful for creating privacy, dividing open areas, blocking visual clutter, or setting up temporary sections within larger rooms. This saved us a ton of time and money in our new studio and enabled us to create a kitchen and office in one room.
The wider feet make a huge difference because flimsy room dividers that collapse every time someone exhales too aggressively are deeply annoying. This one feels more stable and grounded once positioned. The folding design makes it easy to move around or adjust depending on the space, and it folds down relatively compactly when not in use. It is basically the introvert curtain wall of dreams.
The material has a clean, neutral look that blends well into different room styles without screaming “temporary office cubicle panic.” It works well for apartments, studios, shared spaces, dressing areas, or simply hiding the mountain of chaos you swear you are going to organize tomorrow. Practical, portable, and refreshingly easy to use without turning setup into a three hour emotional event.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 16, 2026