The piston pin (depending on the design of the crank mechanism) either moves freely or is firmly fixed in the upper head of the connecting rod. In the case of a floating pin fit, the upper connecting rod head is made with a bushing.

1. E-CLASS T-Model (S210)
2. E-CLASS Break (S210)
3. E-CLASS (W210)
4. E-CLASS Saloon (W210)
5. C-CLASS (W202)
6. C-CLASS Saloon (W202)
7. C-CLASS T-Model (S202)
8. C-CLASS Break (S202)
9. E-CLASS T-Model (S211)
10. E-CLASS (W211)
11. E-CLASS Saloon (W211)
12. V-CLASS (638/2)
13. VITO Bus (638)
14. M-CLASS (W163)
15. M-CLASS SUV (W163)
16. VITO Van (638)
17. S-CLASS (W220)
18. S-CLASS Saloon (W220)
19. C-CLASS (W203)
20. C-CLASS Saloon (W203)
21. See more in applications

The operation of the connecting rod bush

The connecting rod bushing is a part made of bronze or other metal / alloy, which is inserted into the piston head of the connecting rod (it is also called the upper one), the one that is smaller in diameter. This bushing is a ring that acts as a circular bearing for the piston pin. It has a hole through which oil is supplied, which can enter there in two ways: either through the lower head of the connecting rod and the inner channel in the rod, or directly into the upper head.

Since the MAHLE ORIGINAL brand Small End Bushes, connecting rod is a replaceable part, naturally, it must be worn out and replaced, like any consumable. The reasons for the failure of the bushing can be:

1. mechanical wear;
2. malfunction of the connecting rod bearing or its rod and, as a result, deformation of its heads and bushings;
3. lack of oil or its excessive thickness (oil rarely changes);
4. incorrect thermal mode of the motor (frequent temperature rises due to long operation, etc.).