ACHY LEAKY PUMP

In­stalling seals on a VW in­jec­tion pump— in the drive­way

Ultimate Diesel Builder's Guide - - Contents -

Not long af­ter he pur­chased a low-mileage non-cheater 2002 VW Jetta TDI, my son Kyle Tobin (a reg­u­lar UDBG con­tribut­ing ed­i­tor and pho­tog­ra­pher—ed.) be­gan to no­tice that he was get­ting re­duced fuel mileage as well as a diesel fuel smell at times. Af­ter in­ves­ti­gat­ing, we found that the in­jec­tion pump seals were be­gin­ning to leak, which is a com­mon prob­lem for the ALH en­gines. Since the pump seemed to be de­liv­er­ing fuel to the cylin­ders just fine and was not spray­ing fuel out from the high-pres­sure side we de­ter­mined it was leak­ing on the low-pres­sure side.

Rather than re­plac­ing the 11mm In­jec­tion pump with a ques­tion­able used pump or ex­pen­sive re­man­u­fac­tured or new pump we spoke with our friend Kraig Keith at Kraiger Automotive Ser­vice in Lima, Ohio, about send­ing the pump up to him for new seals. He let us know that the low-pres­sure seals can be re­placed while the pump is on the car and he would be in the area and was able to help us out. So we took Keith up on the of­fer and sched­uled an af­ter­noon to get to­gether and wrench on the Jetta.

Keith re­placed the seals in the ALH in­jec­tion pump in about two hours, in­clud­ing time for our pho­tog­ra­phy slow­downs, while work­ing in the drive­way. To seal the pump, he in­stalled a Vi­ton pump head O-ring kit from Diesel­geek along with a Quan­tity Ad­juster seal and Pump Top seal from ID Parts. Be sure to thor­oughly clean the pump and fuel lines be­fore start­ing to work to pre­vent dirt and de­bris from con­tam­i­nat­ing the fuel in­jec­tion sys­tem. Spray brake cleaner will typ­i­cally work well un­less your pump is ex­tremely dirty.

Re­plac­ing the pump head O-ring seal re­quired re­mov­ing the fuel lines and then loosen-

ing the pump head and cut­ting the old O-ring to re­move it, then care­fully slid­ing the new O-ring over the head and into po­si­tion. The kit in­cludes two O-rings in case one gets messed up dur­ing the in­stal­la­tion. The Quan­tity Ad­juster and Pump Top seals were also re­placed as a pre­cau­tion while Keith was ser­vic­ing the pump. He used VAGCOM or VCDS to ad­just the pump IQ to his pref­er­ence of 3.0 to com­plete the re­pair.

Fol­low along over the next sev­eral pages for an over­view of the process, tak­ing no­tice that we don’t have the space avail­able to show ev­ery step—but you will get the gen­eral idea. The Diesel­geek web­site fea­tures a thor­ough set of in­struc­tions for the pro­ce­dure if you need ad­di­tional ref­er­ences. If you plan to re­pair a leaky in­jec­tion pump on your ALH TDI your­self, plan to set aside an af­ter­noon or evening and be sure to prac­tice safe shop tech­niques and if any­thing you see here seems be­yond your me­chan­i­cal skills and abilities have your lo­cal per­for­mance diesel spe­cial­ist han­dle the re­pair work for you. Just be sure to tell them your friends at Ul­ti­mate Diesel Builder’s Guide sent you. UDBG

Kyle Tobin’s lit­tle 2002 Jetta TDI is a fun daily driver that’s great for week­end blasts down the track in bracket races, but its leaky fuel pump seals needed to be re­paired.

1 The 1.9L ALH TDI en­gine from VW is a hearty en­gine, but this one was a lit­tle sick with leaky in­jec­tion pump seals (which can’t be seen with the en­gine cover in place).

4 Here is the Bosch in­jec­tion pump for the ALH, since Tobin’s car is an au­to­matic (but will soon re­ceive a 6-speed man­ual trans­mis­sion swap) it has the de­sir­able high-out­put 11mm pump so it was much bet­ter to re­seal than to re­place.

3 Keith starts by dis­con­nect­ing the neg­a­tive ter­mi­nal on the bat­tery.

5 Keith re­moved the up­per half of the tim­ing belt cover to ac­cess the pump pul­ley to be able to man­u­ally crank it into po­si­tion later on dur­ing the in­stall.

6 He starts get­ting into the pump by re­mov­ing the low-pres­sure feed and re­turn lines from the fuel fil­ter to the pump as well as the in­jec­tor re­turn line.

2 The seal kits from Diesel­geek and ID Parts in­clude the seals Kraig Keith needs to do the mi­nor pump on-the-car re­seal as well as other seals for a com­plete off-the-car re­build. Note that the Bosch seal kit uses a Buna rub­ber seal (large green O-ring) that does not re­turn to its shape very well af­ter be­ing stretched over the pump head, so Keith and Diesel­geek.com rec­om­mend us­ing the Vi­ton O-ring from them for an on-the-car re­seal (they even sup­ply an ex­tra O-ring).

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