What You're Looking At
This is an outboard-mount drum, 18x7 size, 10 bolt pattern, 11.25" diameter. That combo tells you it's a heavy front or drive axle application, not a trailer piece. ConMet stamps this casting as CV70773 — that's the number you'll usually find on the drum itself if it's already on the truck.
Volvo runs the same drum under their own part numbers — 3915901, 8098794, 8180825, 8180826. Different Volvo/Mack VDS trucks and build years pulled from different suffix runs of that casting, which is why you see four Volvo numbers instead of one. Same drum, same tooling, different label on the box.
Why These Numbers Cross
ConMet supplies drums to Volvo/Mack as an OE vendor, so the CV70773 casting shows up under both brand names. The Volvo numbers aren't a coincidence — they're the same physical drum, just sold through the Volvo parts channel with a Volvo part tag on it.
What to actually check before you order: outboard vs inboard mount (don't mix them up, they don't interchange), bolt pattern count and spacing, and drum width matching your brake shoe width. 18x7 is common but there are 18x8.625 and other widths floating around on similar-looking castings — measure or pull the old drum's stamped number before you commit.
If your old drum has any of the numbers in the chart, this cross-references. If it's stamped something else entirely, call us with the number off the drum or give us the VIN and we'll run it before you buy.
Ordering From PartStop
We stock this drum in Tacoma for will-call or same-day pickup if you're local, and we ship nationwide for fleets that need it faster than a dealer counter can turn it around.
This is an aftermarket drum, not a Volvo-branded part, but it's built to the same casting specs and comes with our standard 6+ month warranty. Price is $179.99 each — check if your application needs one or a pair before you order, some setups run drums in matched sets.
66665B Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to 66665B. Use them to identify the part — then confirm the exact fit by VIN or the number stamped on your old unit before you order. An interchange is a starting point, not a fitment guarantee.
| Brand / Line | Cross-Reference Numbers |
|---|---|
| ConMet | CV70773 |
| Volvo | 3915901, 8098794, 8180825, 8180826 |
Frequently asked questions
Does 66665B fit my Volvo VNL?
Depends on the axle and build year — Volvo used this casting across several VNL configurations under four different part numbers. Give us the number stamped on your old drum or your VIN and we'll confirm before you buy.
Is this the same as the Volvo 8180825 drum?
Same casting, yes — ConMet builds this drum for Volvo under their own numbers too. This is the aftermarket version of that same 11.25" outboard drum, not a Volvo-branded part, but it's built to the same dimensions.
How do I know if I need outboard or inboard mount?
Pull the old drum and check where the mounting flange sits relative to the wheel hub — outboard sits toward the wheel side. Mixing them up means the drum won't seat right. If you're not sure, snap a photo of the old drum or bring it to the counter and we'll match it up.
Not sure it fits? We check before you pay.
Run your VIN and we’ll match parts to your exact truck, or call the counter — a person who knows trucks verifies fitment by OEM number before the order ships. No wrong-box returns.
More cross-reference guides
Need the part, not just the reading?
Every part below is a Premium Quality aftermarket Direct Replacement with published OEM cross-reference numbers, a 6+ month warranty and same-business-day shipping from Tacoma, WA. Not sure it fits? Run your VIN — or call and a person who knows trucks will verify fitment before you pay.