TheSamba.com :: View topic - Consensus on expected lifespan of a mechanical fuel pump?

Fri Aug 15, 2014 1:05 pm

When it comes to the fuel system, there are a number of parts that many people replace on a routine schedule for safety or reliability reasons. (Fuel lines every 4 years, fuel filter ever 2 years, accelerator pump diaphragm every xx,xxx miles, etc, etc.)

But what about the mechanical fuel pump? :?:

It's still a diaphragm exposed to fuel... constantly flexed throughout its life. So it's not going to last forever. Searching for opinions, it seems as though people generally only replace them when they have problems - being stranded from a breakdown, not getting enough fuel to the carb to run correctly, pump making noise, fuel in the oil, etc. I'm not finding many reports at all of someone saying they replaced or rebuilt a fuel pump as part of a general scheduled preventative maintenance routine.

So what's the consensus, and/or what is your personal opinion? How long does a fuel pump generally last, how long would you expect it to last, and do (or should) you rebuild or replace one at any particular service interval (miles or years)? :?:
(Sealed/crimped type vs rebuildable, original vs aftermarket, any brand/manufacturer, any engine age/displacement, etc, etc.. are all free game for discussion. :wink: )

Fri Aug 15, 2014 1:17 pm

For reference, I should start off with this quote from the 66-69 Bentley service manual:
Quote: The fuel pump causes almost no problems. The moving parts are splash-lubricated continuously from the crankcase, and the cleaning of the filter is the only regular maintenance required. Table 'e' in LUBRICATION AND MAINTENANCE specifies the intervals for this cleaning.
Table 'e' says to clean the fuel pump filter at 300 miles after a major overhaul, and at every 6,000 miles.

Of course, this is based on the multi-piece serviceable fuel pump design, and doesn't take into account the effects of the ethanol content in modern fuels. By contrast, some of the aftermarket non-serviceable pumps without a filter have reports of repeated failures in <2 years after installation.

Fri Aug 15, 2014 3:55 pm

It also doesn't take into account the fact that some of these are now 40+ years old.

Max

Sat Aug 16, 2014 12:30 am

I would say 5 years on a daily driver.
5-6 years ago I have installed a mechanical fuel pump, similar to this one: http://en.hoffmann-speedster.com/beetle/engine/fue...e?c=110378

It has worked great on a couple of engines I had - until early this year when I had some issues with the fuel supply going weak during certain moments during driving. Replaced the fuel pump with an identical new one and those problems went away.
I have inspected the old fuel pump and the diaphragm appeared to be still intact, and did not notice any other flaws overall, but who knows.

Sat Aug 16, 2014 7:31 am

My Brazilian lasted 2 years, so don't go there. I had to tow it home 3 times before I figured it out that it would quit working after it heated up. the return spring on the lever wore out.

Sat Aug 16, 2014 3:10 pm

My 64 VW 113 deluxe beetle 40 hp fuel pump has been on the engine since 1966, It's got 172,000 miles on it.
My 65 111 "A" Sedan 36 hp has it's original fuel pump...I rebuilt the engine in 1973 and bought a fuel pump rebuilding kit but have never taken the pump apart to install it.
My 76 Oldsmobile has it's original fuel pump @ 112,000 miles.
My 69 455 Pontiac received a new pump when I rebuilt the engine in 1992.
The Olds and Pontiac have mechanical pumps.

Sat Aug 16, 2014 7:36 pm

1960 single cab with 1963 1500 engine was rebuilt around 1988 and still has the same fuel pump.

1968 westy, 1500 sp engine rebuilt in 2011 with same fuel pump.

1952 Zwitter was rebuilt around 1980 and still has the same fuel pump.

Sun Aug 17, 2014 5:12 am

1959 36 hp with original pump- at about 173k miles one of the internal springs broke, causing fuel starvation at 45mph+. Springs from rebuild kit solved that issue, and replaced diaphragm at that time as the broken bit of spring poked a tiny hole in it.
My suggestion would be to add a rebuild kit to the spares kept in the car

Mon Aug 18, 2014 7:54 am

I bought 2 original used VW piersburg mechanical pumps, and rebuilt a solid replacement out of parts from both, using a WW rebuild kit. I pulled my working-just-fine rebuildable Brazilian pump, cleaned it, packed the base with grease, and sealed it in a bag. I pack this with my spare cables, tools, etc..

The rebuild kit cost more than the two old pumps, if I remember right!

Fri Aug 22, 2014 9:35 pm

Wow, some of those have gone a LONG time! :D

Here is a relevant post I found in another thread.
http://www.thesamba.com/vw/forum/viewtopic.php?p=6000674#6000674

Braukuche wrote: Here's a pic of the NOS German diaphram I found in a parts stash, it has a 60,000KM guarantee!