2008 GL550 power steering reservoir replacement

[teb1015]

When reinstalling the reservoir to the power steering pump is it absolutely necessary to install the c-clip in the back or are the 3 bolts sufficient to hold the unit and prevent it from leaking? It is extremely difficult to access the tube that the c-clip snaps onto.

[Paulwho]

it is absolutely necessary to install the c-clip or it will leak