PD (BEW) tandem pump FYIs

[gforce1108]

My tandem pump has been seeping for quite a few years - just not enough for me to fork over $350 or so... I had one small hose get soft a year or so ago from fuel dripping on it (relocated), but otherwise it's been trouble free. Unfortunately, it's now stated making a mess of the driveway. I replaced it yesterday and figured I'd share a couple of tidbits of information:

First - The Bentley manual states that you have to prime the new pump by pulling vacuum on the return line - there was no way that was going to happen... my pump just sat there at full vacuum. I assume it's the newer style lift pump that you can't 'pull' though? I cycled the key a number of times and then had to crank it a while.

Second - ever since I installed a working lift pump, I've heard a 'squishy' sound when first turning the key to 'on'. I assumed it was normal (pump was dead the first few years I owned the car). That noise went away with the new tandem pump. As diesel leaked out, a small amount of air must have been leaking in I assume? If you hear a squishy, bubbly sound under the rear seat, check your tandem pump.

 

[jasco]

Did you put any thing on the tandem pump gasket prior to installing? Like high temp RTV. I'm not convinced those crappy metal gaskets seal all that well. I just found out my lift pump is bad after replacing my tandem pump gasket. So I'll be putting a new lift pump in as well as another new tandem pump gasket. Thanks for posting your tips. Jasco

 

[gforce1108]

No sealant used - I cleaned the area with brake cleaner and torqued the 4 bolts to spec. So far - no leaks.

At first I thought it was just my imagination, but it's definitely running better than before. It always ran great, but it feels so much more smooth now. Noticeably less vibration when driving and better acceleration.

 

[burpod]

also be very careful with the gasket placement - when replacing the cam/tb in my gf's 06 golf, i noticed the gasket had been kinked when i removed it. i don't remember if it was leaking (maybe slightly), so somehow it had still been sealing. i believe the dealer messed it up when it was in for a recall early in its life. i never used sealant on any of the BEW tandem pump gaskets i've done, and no leaks. vw uses those type of gaskets in many places and i've noticed no tendency to leak

 

[gforce1108]

I was a little concerned at first - the gasket was damaged in shipping. Fortunately, the damage was not at any of the sealing surfaces.

 

[gforce1108]

We are referring to the head to pump gasket - the one you'd need when replacing the pump. There are some preinstalled blue sections on the gasket - you are correct.

I had thought about trying to 'fix' mine, but at 200k with a loose vacuum port and the possibility of an internal failure mixing fuel and oil, I decided to just bite the bullet and replace it.