Are there any problems with a Mercedes vacuum pump?
Typical Mercedes diesel vacuum pump. They are very reliable and easy to rebuild if need be. The most common failure is the check valve and internal diaphragm. The very first thing I do is make sure we have a constant supply of vacuum.
How to tell if your Mercedes W123 vacuum lock is leaking?
Connect your vacuum gauge to the line just disconnected from the first “Y” 3-way connector inside the car. Pump a vacuum of 10 to 15Hg. If this line shows a leak, it means this line is cracked, likely where it passes between the body of the car and the door. If it does not, the line is OK. Make note of the results and continue.
Where is the vacuum tank in a Mercedes?
Vacuum tank is pictured, in trunk, under hat shelf. Move your vacuum pump to the yellow solid line with no stripes for the next step. With your hand vacuum pump connected to the solid yellow line, with no stripes, you can continue. Make sure the driver’s side door is closed, and turn the key to the lock position.
How can I lock my Mercedes W123 door?
Pull this line from the “Y” connector, attach your vacuum pump and draw a vacuum of 10 to 15Hg on this side of the system. If the rear driver’s side door is unlocked, doing this should lock it. Watch the gauge for a short time and look for vacuum leaking off.
How to test a Mercedes W123 vacuum lock system?
Pull all three lines from the check valve and test it. Use your mouth to suck and blow in to the single connection side of the check valve. If you can suck AND blow, the valve is bad and will need to be replaced. If air will only travel one way, the valve is OK. Connect your hand vacuum gauge to the yellow line with the grey stripe.
Vacuum tank is pictured, in trunk, under hat shelf. Move your vacuum pump to the yellow solid line with no stripes for the next step. With your hand vacuum pump connected to the solid yellow line, with no stripes, you can continue. Make sure the driver’s side door is closed, and turn the key to the lock position.
Where is the check valve on a Mercedes W123?
Begin under the hood of the car, on the driver’s side, back near the large round brake booster. You will see a yellow check valve with two connections coming from it. One connection is a 3-way “Y” connection with two yellow lines coming out of it.
How to fix a Mercedes W123 door lock leak?
Note – if you find that part of your leak is due to old and cracked diaphragms on your early style door lock vacuum actuators, see the repair guide under the Mercedes W123 repair section to learn how to fix these without replacing the entire assembly. Begin under the hood of the car, on the driver’s side, back near the large round brake booster.