Mechanical vs electrical FP

[HWooldridge]

I've had my stock M37 for about 15 years and have had to kit the fuel pump at least four times. The last time was this past September and the diaphragm has already failed. The kit came from someone recommended here - can't recall his name at this moment. Prior to that, I think #3 lasted a couple of years. I run regular unlead and add Stabil but I think our modern junk gas is killing them.

At this point, I'm irritated enough to just install an electric pump next to the fuel tank and pipe it through the mechanical and be done with it. Any thoughts on this plan? Does anyone make a diaphragm that will last more than a few months? The only other thing I can think of is to go to the airport and buy a barrel of leaded av gas.

[Matthew Welcher PWA]

Vintage Power Wagons has the dual diaphragm M series pumps that are compatible with modern fuel. I have installed a ton of them and haven't had problems.

[HWooldridge]

VPW is where I bought the diaphragms. I kitted it myself but I have never had a problem with rebuilding them and having them work properly at installation - they just fail sooner than later.

[oldmopar]

I have run a few vehicles on 6V electric fuel pumps no problems but the can die without a warning so best to carry a spare pump to be safe.
Need to be careful about running the electric through manual I think if the diaphragm fails you may pump gas into the engine.

[HWooldridge]

I fiddled around with it some more and the problem might be one or more of the check valves. I have not pulled the pump off the truck but when dribbling gas into the line from the carb, the level leaks down. I also get some weak spurts when pumping the manual priming lever, which might indicate the diaphragm is still OK but there is some trash in a valve. I have an inline fuel filter just ahead of the pump but that may not catch everything.

[Matthew Ziegler]

fuel pump

I replaced the stock 2 chamber pump on my m37 with one for a civilian power wagon rebuilt by a guy I found in hemmings 5 or so years ago, no problems, contact a few rebuilders and find out if they use a diaphragm that'll stand up to modern fuel. If your interested I think I have a spare rebuildable civilian pump laying around.

[HWooldridge]

I replaced the stock 2 chamber pump on my m37 with one for a civilian power wagon rebuilt by a guy I found in hemmings 5 or so years ago, no problems, contact a few rebuilders and find out if they use a diaphragm that'll stand up to modern fuel. If your interested I think I have a spare rebuildable civilian pump laying around.

Hi Matt,

Thanks for the offer; I have several of the two chamber bodies and am trying to keep this truck stock but that may not work over the long haul. Just out of curiosity, are you running stock vacuum wipers and if so, where are they connected?

Thx, Hollis

[Matthew Welcher PWA]

I don't believe we have any repair parts here other than the diaphragms. I can do some digging for you if you would like. For the vacuum wipers I believe that if using a civilian pump there is a port on the manifold towards the firewall that will work to run the vacuum wipers.

[oldmopar]

The dealer at the links sells rebuilt pumps and rebuild kits. Never used a fuel pump kit from them I did by a manifold heat valve repair kit years ago from them.
http://www.maritimedragracing.com/an...rts_cellar.htm

[HWooldridge]

I haven't messed with the truck for a few days but have been pondering some more on the problem. If the diaphragm is OK and there really is some trash stuck in one or more check valves, might it be possible to push some diesel or cleaning fluid into the inlet side of the pump (perhaps with 20-30 lbs of air pressure behind it) in an attempt to rinse the valves? Has anyone tried it or does it sound sensible?

OTOH, I don't think it would work to blow back on the outlet side because the valves would seat harder on any existing trash. Might make the situation worse and/or burst the diaphragm for certain.

[Matthew Ziegler]

fuel pump

No, I'm no longer using the vacuum wipers, got some cheap electric ones from Kaiser willys that are 24 volt. I had the stock fuel pump, added a vacuum canister, still had little to no luck with vacuum wipers, they work great going down a hill in third. I had one of these pumps apart once or twice, the valves are just a round sheet metal housing with a spring and a piece of bakealite in them should be very simple to clean out and reinstall.

[HWooldridge]

No, I'm no longer using the vacuum wipers, got some cheap electric ones from Kaiser willys that are 24 volt. I had the stock fuel pump, added a vacuum canister, still had little to no luck with vacuum wipers, they work great going down a hill in third. I had one of these pumps apart once or twice, the valves are just a round sheet metal housing with a spring and a piece of bakealite in them should be very simple to clean out and reinstall.

Good idea on the wipers. I have found that cleaning the old vacuum style and reassembling with some white lithium grease works wonders - but they still slow down at high rpms.

I've had my fuel pump apart enough times that the rebuild doesn't scare me - was just trying to avoid the hassle if I could blow it out.

[HWooldridge]

Here's how it ended: I blew air thru the fuel pump to get any debris out of the valves, disconnected and blew out all the fuel lines - and then - I installed a new fuel filter ahead of the pump. Violin! She runs like a top! No need to tear down what appears to be a perfectly good pump. Looks like the real culprit was the old clogged filter (it's usually the simple stuff, eh?)

[Matthew Welcher PWA]

That is good news! And yes usually it is the simplest fix.

[john eickhof]

electric fp for m37

I found it necessary to install an electric 24v fp ahead of the mechanical one for use when traversing very steep climbs, 100% or more, I call it 'turbo boost' as the mechanical pumps have a hard time pulling fuel from the rear tank when climbing a 45-50 degree climb! (like Moab, etc) It also can be used to help alleviate 'vapor lock' problems in the summer. (I have electric pumps as back-up on my PWs too) If it starts to VL, just turn on the electric until the motor runs smooth again! High quality pumps are available from Car-Quest in 6, 12, 24 volt versions. It will run about $70 but well worth it when your doing a hard climb and don't feel like losing power! Have fun!!