Cohline Vacuum Line
Vacuum lines are small parts that do a lot of work. They carry vacuum to brake boosters, HVAC flaps, central locking actuators, distributor advance units and emissions components. When one cracks or hardens, the symptoms can be puzzling: rough idle, a hissing sound, doors that won't lock, or climate flaps that stop responding. Cohline's vacuum line range is built around replacing those aging lines with material close to what the car left the factory with.
A German Fluid-Line Specialist
Cohline traces its roots to 1932 in Germany. The company grew from early engine repair work into a maker of media-carrying lines, and it is known as an original equipment supplier of tube and hose systems to European automakers. That background matters for vacuum hose. Dimensions, wall thickness and material have to match what the vehicle expects, and a supplier used to meeting automaker specifications tends to get those details right. Cohline holds IATF 16949, ISO 14001 and ISO 45001 certifications.
Product Types in Cohline's Vacuum Line Range
Cohline's vacuum line offerings are mostly sold as bulk tubing by the meter, so you can cut the length your repair needs. Common examples include:
- Black rubber vacuum hose, 3.5 x 7.5 mm: A flexible line that is widely used on Mercedes-Benz models from the 1960s through the 2010s, including 190, 300D, 380SL, E320 and C300 applications.
- Rubber vacuum hose, 3.5 x 9 mm: A slightly heavier-walled size listed for a long run of W124, W126 and W201-era models.
- Hard white plastic vacuum line, 1 mm ID x 4 mm OD: A rigid tubing used to carry vacuum from central locking and comfort system pumps to their actuators. Brittle or cracked sections of this line are a common cause of leaks.
Cohline's nitrile rubber vacuum and vent hose is made to DIN 73379 and is rated for roughly -30 to +80 degrees Celsius. That range suits typical under-hood vacuum duty, and the small-bore sizes are a good fit for distributor vacuum advance units and gauge connections.
Choosing the Right Line
Match the inside and outside diameter to the original line, since a loose fit leaks and an overly tight one can crack a nipple. Check whether the original is soft rubber or rigid plastic, because the two are not interchangeable. Because the tubing is sold by length, measure the run, including bends, and leave a little extra for trimming. Replacing a whole brittle section is usually better than patching one split.
Explore More
These vacuum lines are part of a wider lineup of precision fluid-transfer components, which you can see on the Cohline brand page. If you want to compare vacuum hose and tubing from other makers, browse the full Vacuum Line category.