Having already reviewed the Milwaukee M18 Surge impact driver, seeing the new Milwaukee 2551-20 M12 Fuel Surge hydraulic impact driver at the 2019 NPS media event gave us a pleasant surprise. The new impact driver is the first 12V subcompact hydraulic driver on the market.
Check out our best hydraulic impact driver article for how these tools stack up.
How It Works
The Milwaukee M12 Fuel Surge impact driver uses a hydraulic powertrain instead of a metal-to-metal impact mechanism. More traditionally, we call this oil impulse technology, and the tools deliver much less noise and vibration than traditional impact drivers using anvils. They also maintain their peak torque longer than standard impact drivers due to a longer strike duration. They tend to hit slower, but harder, to deliver a more even, and often faster, driving speed over traditional impacts.
The M12 Fuel Surge hydraulic impact driver works well for driving small to medium diameter fasteners. It also seems like a great MRO tool to handle a variety of tasks. This tool makes a lot of sense for anyone already on the Milwaukee M12 platform. Anyone looking for the power and flexibility of an impact driver, but with less noise should also take a close look at this tool.
Since the Milwaukee M12 Fuel Surge runs quieter than standard impact drivers, it works really well indoors. It seems particularly well-suited for any work done in an occupied building or for close-quarters work. It’s only too bad it wasn’t around in time for our best impact driver review article.
First of Its Kind?
While this tool certainly isn’t the first cordless hydraulic impact driver on the market, it is the first 12V tool using this technology. We already prefer 12V or subcompact tools over 18V for MRO work or anything that doesn’t require the bulk or premium power of 18V tools.
The Nitty Gritty
This tool can drive fasters at higher setting speeds over a standard impact—in many applications. And with 450 in/lbs of sustained torque, the new tool delivers unmatched performance.
|M12 FUEL Surge||M12 FUEL Impact|
|Speed (RPM)||0–1100/2200/3200 RPM||0–1300/2400/3300|
|Price (bare tool)||$149||$129|
Milwaukee 2551-20 Performance
Let’s just start by saying the Milwaukee 2551-20 M12 Fuel Surge is an incredibly impressive tool. Starting with power, we’re seeing fastening torque that’s not too far from the M18 Fuel Surge.
The M18 Fuel version took 1241 in-lbs to break and the M12 Fuel averaged 1026 in-lbs. Against standard 12V impact drivers, it is significantly higher torque than any other model—including the M12 Fuel Surge 2553.
*Note – we measure fastening torque by the amount of torque it takes to break a fastened nut on our rig. The result is not intended to replace manufacturer’s specifications. Check out our best impact driver article for more info.
In terms of nut-busting torque, the Milwaukee 2551 Surge consistently broke 2400 in-lbs (200 ft-lbs). Like its fastening torque, it’s stronger than any of the 12V impact drivers we’ve tested.
Milwaukee 2551-20 Speed
The compact Surge’s speed is solid, too. In our 1/4″ ledger screw test, it averaged 346 RPM. That’s well under what the 18V hydraulic drivers did, but only its M12 Fuel impact driver cousin had the speed to outperform it among 12V impact drivers.
At 87 decibels, the Milwaukee M12 Fuel Surge is 7–13 decibels quieter than any of our 12V impact drivers. That may not seem like a huge difference, but it actually is.
Splitting the difference in that range, the Surge sounds half as loud as a regular 12V impact driver. And when it comes to sound pressure level, it’s actually 10X softer.
Milwaukee M12 Fuel Surge Hydraulic Impact Driver Price
The price is roughly a $30 premium over the most current M12 Fuel impact driver.
The Bottom Line
18V hydraulic impact drivers force you to trade off performance or bulk to get their quieter, less violent operation. But that’s not the case here. The Milwaukee M12 Fuel Surge hydraulic impact driver is a no-compromise 12V impact driver replacement. Aside from Milwaukee’s M12 Fuel impact driver, it outperforms all of its 12V competition handily.
There’s a slight weight penalty and premium on the price for its convenience, but we think it’s well worth it for MRO in occupied spaces.