The brake vacuum pump on the MK5 GTI (or any car with the TSI motor) is prone to failure. The main point of failure is a leaking gasket which causes a vacuum leak and directly affects braking performance. Luckily, replacement of the pump or just the seal is a straightforward process that anyone can tackle. Charles (HumbleMechanic) Sanville explains how the system works and demonstrates just how easy it is to do yourself.
Tools needed to replace or reseal your Brake Vacuum Pump:
Parts needed to replace or reseal your Brake Vacuum Pump:
Steps to replace or reseal your Brake Vacuum Pump:
Step 1: Remove Screws from Vacuum Pump
The brake vacuum pump is held in place by three T30 Torx screws. Two on the top side of the pump, and one on the underside. The one located on the underside also fastens a bracket to the pump. Use caution working around the coolant hose just forward of the pump. It's fragile, and if the car is warm, you can end up being scalded by hot coolant.
Step 2: Disconnect Brake Booster Hose
The brake vacuum pump has only one hose connected to it. This hose is what supplies the vacuum for your brake booster. It is easily removed by gripping at the elbow and pulling it straight out. There is a separate rubber grommet that goes in the end of the fitting. This grommet has a tendency to stay connected to the vacuum pump. If that's the case, be sure to remove it - especially if you're replacing the entire pump.
Step 3: Remove Vacuum Pump and Gasket, Clean, and Install New Gasket
Now you can wiggle the vacuum pump right off the timing cover. Once you have it off, you can go ahead and either install your new unit or clean your old one and install a new gasket. To clean the pump, use brake clean or a mild degreaser with a soft brush. Once it's all clean, you can install the new gasket. Be sure to lubricate the new gasket with a small amount of clean engine oil. Make sure the new gasket is free of defects and that it sits properly inside the groove. The smallest discrepancies will result in another leak.
Step 4: Reassembly!
Installing your new (or newly sealed) pump is an easy process; there are only a couple of things to note. First, it's important to make sure mating surfaces are clean. You have to align the pump to the channel in the camshaft. If it isn't aligned, it's impossible to install. Once aligned, you can wiggle the pump into place and thread the screws by hand. A touch of clean motor oil for lubrication can't hurt during this process.
Don't forget that the bottom screw also retains a bracket. Be sure that this bracket is sitting flat/flush against the pump before tightening the screw. Failure to do so can result in a cracked pump. Torque spec on these screws is 4Nm. Reattach the brake booster hose and you're in business!
Just like that, after a few simple steps you have a clean, leak free, brake vacuum pump.
Be sure to check the video below on HumbleMechanic's YouTube page, and don't forget to subscribe to get all new videos pushed right to your inbox.
Writer/Editor at FCP Euro and owner of a daily R53 MINI Cooper, a track-built R53 MINI, and a 1997 Dakar Yellow E36 M3 Sedan. ••• Instagram: @evan.madore