2012 Volvo S60 & XC60 Brake Vacuum Pump: Diagnosing and Fixing the Common Oil Leak

The #1 Problem: A Major Oil Leak

The most common failure for the vacuum pump on the 2012 Volvo S60 and XC60 isn't a loss of braking power, but a significant engine oil leak. The seals and O-rings inside the pump assembly become hard and brittle from heat and age. This allows engine oil to seep out, typically from the seal between the pump and the engine, or the seal between the two halves of the pump body.

This leak can be severe. Owners often find oil dripping onto the top of the transmission case, the driver's side control arm, and eventually onto the ground. Because of its location, the leak is frequently misdiagnosed as a leaking transmission seal or a rear main seal, which are much more expensive repairs. If you see oil on the driver's side of your engine bay, the vacuum pump is the first place you should inspect.

Symptoms of a Failing Vacuum Pump

While an oil leak is the most prominent sign, other symptoms can also point to a failing vacuum pump.

• Obvious Oil Leak: This is the primary symptom. Look for fresh, dark oil coating the top of the transmission, behind the engine on the driver's side.
• Stiff or Hard Brake Pedal: If the pump fails internally and can no longer create a vacuum, you will lose power brake assist. The brake pedal will become very difficult to press, and stopping distances will increase significantly.
• Hissing or Whistling Noises: A hissing sound from the engine bay could indicate a vacuum leak from the pump's hoses or the pump body itself.
• Check Engine Light: In some cases, a malfunctioning vacuum system can trigger diagnostic trouble codes (DTCs) related to vacuum-dependent components, illuminating the check engine light.

Known Issues, TSBs, and Recalls

As of early 2026, there are no specific recalls or Technical Service Bulletins (TSBs) from Volvo or the NHTSA for this mechanical vacuum pump on the 2012 S60 and XC60. The issue of leaking seals is a widely known problem in owner and mechanic communities but has not been addressed with a formal campaign. Recent NHTSA warnings about Volvo brake issues apply to much newer hybrid and electric models with software-related problems and are not relevant to this mechanical pump.

Repair Option 1: Resealing the Pump

Because the pump itself is a simple and durable mechanical part, the internal components rarely fail. The problem is almost always the rubber seals. For this reason, many owners choose to reseal the original pump instead of replacing it. Aftermarket seal kits are available that often use Viton rubber, which is more resistant to heat and oil than the original seal material.

A reseal kit typically includes:

• The main O-ring that seals the pump to the engine block.
• A square-profiled gasket that seals the two halves of the pump body.
• A new check valve and its small O-ring.
• New Torx screws for the pump body, as the old ones can be greasy and easily stripped.

Resealing is a cost-effective option for DIY mechanics comfortable with disassembling the pump.

Repair Option 2: Replacing the Pump Assembly

Replacing the entire pump is a more straightforward, though more expensive, option. You can choose between a new OEM pump, a new aftermarket pump, or a used OEM pump.

Buying a Used Vacuum Pump: What to Check

A used OEM vacuum pump is an excellent value, as the pump mechanism is very reliable. When buying a used unit, you are primarily getting a good core to either install directly or reseal with an upgraded kit for maximum longevity.

• Verify Part Numbers: Match the part number on the listing to your old part. Known compatible numbers include 31329920, 31340067, and 313400673.
• Inspect the Housing: Check photos for any cracks or significant damage to the aluminum body.
• Check the Drive Tang: Ensure the metal tang that engages with the camshaft is not bent, cracked, or excessively worn.
• Consider Mileage: A pump from a lower-mileage vehicle is preferable, as its seals may have more life left. However, given the high failure rate of the seals, it's wise to plan on resealing any used pump before installation.
• Why Used OEM is a Good Choice: The original Volvo/Pierburg pump body is a high-quality casting. A used OEM part, especially when fitted with a new, upgraded seal kit, can be more reliable than a cheap, new aftermarket unit of unknown quality.

Cost Comparison

Installation Guide & Difficulty

Replacing the vacuum pump is a moderately easy job for a DIYer with basic tools. The main challenge is accessing the pump, which is tucked behind the engine.

• Difficulty: 2/5
• Estimated Time: 1.5 - 2.5 hours

Step-by-Step Overview:

1. Disconnect the Battery: Always disconnect the negative battery terminal before starting work.
2. Remove Airbox and Battery: To access the pump, you will need to remove the engine air filter box and the battery, along with the battery tray. This will clear the space needed to work behind the engine.
3. Disconnect Hoses: Unplug the quick-disconnect vacuum hose from the pump. It may be stiff, but it pulls straight off after squeezing the release tabs.
4. Remove Mounting Bolts: The pump is held to the engine by two bolts. Remove them.
5. Remove the Pump: Wiggle the pump and pull it straight out from the engine. Be prepared for some oil to spill out.
6. Installation: Before installing the new or resealed pump, clean the mounting surface on the engine. Lubricate the new O-ring with clean engine oil. Note the orientation of the slot in the camshaft and align the drive tang on the pump to match it. Slide the pump into place, reinstall the bolts, reconnect the hose, and reassemble the battery and airbox.

Frequently Asked Questions (FAQ)