Note: If the water pump is faulty, it is best to replace it entirely. However, you can limit yourself to replacing the seal and shaft with bearing.
Cross section of water pump
- a = 25,8 - 26,2 (22,8 - 23,2) mm
- b = 2.0 mm
1 - shaft and bearings (in the figure the pump is shown with an electromagnetic fan); shaft with fan with viscous coupling is longer); 2 - hub; 3 - casing; 4 - sliding ring seals; 5 - sealing ring; 6 - retaining ring; 7 - impeller
1. Secure the water pump to a section of metal pipe with the impeller facing upwards; then, using a soft metal punch, press the shaft through the impeller, and the shaft with bearings through the pump body. Remove the impeller.
2. Press out the sliding ring seal using a drift directed from the outer end of the pump.
3. Remove the center and spacer rings from the impeller.
4. Clean the pump body and impeller with kerosene and wipe dry. Keep in mind that the shaft and bearings together with the fan hub and sealing parts must be replaced with new ones.
5. Fix the pump body with the impeller facing downwards, then install the mandrel (piece of metal pipe) onto the outer raceway of the bearing and press in the new shaft and bearing so that the raceway is flush with the end of the housing.
6. Place the pump body with the impeller facing upwards and lubricate the O-ring seat in the body with sealing paste.
7. Using a mandrel (metal tube) press the O-ring into the housing at a right angle.
8. Place a new sealing ring on the thrust ring. Then lubricate the sealing ring with brake cylinder paste and press the ring into the impeller with the beveled side first.
9. Clean the shaft, impeller seat and sealing surfaces, then place the shaft on the support and press the impeller flush with the end of the shaft. Check the dimension "a" (see illustration Cross section of water pump).
10. Heat the new fan hub until it turns blue (approximately 300°C). Clean the shaft and install the hub using a 2mm metal spacer. Place the hub on the mandrel (metal tube), insert the shaft and press it down to the adjusting shim. Wait until the hub grips the shaft tightly, then dip it into the bottom and remove the spacer.
Article borrowed from the web portal MERCEDESMAN