159601-6620 ZEXEL 9 421 621 288 BOSCH ADJUSTING DEVICE 9421621288 1596016620 227102010a

Introduction
The problem that is identified below does not have a known permanent solution. Until a permanent solution is known, use the solution that is identified below.Problem
Premature wear of 162-2220 Check Valve in the 217-7455 Fuel Filter Base can cause low fuel pressure or injector malfunction.Solution
There are two solutions that can deal with the problem stated above and are listed below :
Replace the 162-2220 Check Valve with a new part.
Install an external check valve on the high-pressure outlet of the 217-7455 Fuel Filter Base .The procedure that follows below covers the process of installing an external check valve on the outlet of the pump. Table 1 lists the parts needed to install the external check valve.
Table 1
Item    Qty    New Part Number    Part Description    
1     1     238-5080     O-Ring Seal    
2     1     238-5081     O-Ring Seal    
3     1     305-6991     Elbow    
4     1     420-1796     Check Valve    
Illustration 1 g03420967
Install elbow (3) with o-ring seal (2) into the outlet of the fuel filter base.
Install check valve (4) with o-ring seal (1) into elbow (3) .
Illustration 2 g03421982
Install the fuel hose back onto check valve (4). Check for any leaks after installation.