Leaky Fuel pump diaphragm

[isaac_alaska]

noticed the fuel pump was leaking around what i assumed was the gasket, because i didn't know how the fuel pump worked. tightened the screws and the leak slowed but didn't stop, but it was enough to get back. took it apart and there was quite a bit of dirt and junk between the two halves where they seal, and the diaphragm rubber is fairly cracked, but doesn't look like it's actually broken anywhere. I cleaned up the mating surfaces and the diaphragm and put it all back together and the leak has stopped, but i think i should probably replace the diaphragm before it leaks again or cracks. Are NOS diaphragms any good? I can buy a NOS diaphragm from vintagepowerwagons for about 39 bucks, or a full new fuel pump for 79. i'm thinking i'm probably best off just replacing the whole pump and not having to worry about it, yeah?

[Tuko]

Stay away from any nos seals. Any rubber that has been sitting on a shelf for 20-65 years is no good. I can't understand why they still sell them. Google Now and then automotive, they have new production rebuild kits for our factory fuel pumps.

[isaac_alaska]

i will check them out, thanks! i saw the rebuild kit that vintage sells but it looks like it comes with everything but the diaphragm....

i did pull the fuel pump from a 30's era plymouth which is sitting in my yard, and believe it or not there are no cracks in the diaphragm on that one. it looks to be two plys of some kind of tight weave cloth, and 3 plys of rubber. very nicely made and still flexible.the plymouth pump is a direct replacement for the one in the M37. different style but same bolt pattern and lever arm on it. i'll post pics of both if i rememember to get around to it.

[w30bob]

Ummm...............I think it's Then and Now Automtive.

Here's the link;

http://then-now-auto.com/fuel-pumps/

regards,
bob

[Jess]

Keep in mind that the stock M37 fuel pumps had both the fuel pump and the vacuum section. Most Dodge fuel flat head pumps will fit up but you will not have the vacuum section for your wipers. If you have converted to electric, then that's not an issue. Gas with any appreciable percentage of ethanol will eat up the old rubber on our trucks. Using a new diaphragm made of material resistant to this will ensure a lasting repair.

[MSeriesRebuild]

1 chance to do this right. A cracked diaphragm will dump gas directly into the oil pan. Only a few minutes of running like this will destroy the engines lower end by diluting the oil. The BEST thing you can do is remove the original pump, install a plate over the opening in the block; then install a quality in-line electric fuel pump that has a max PSI rating of 4-5.

I've been asked many times, can't an electric pump fail and leave me stranded? Sure, any fuel pump failure will leave you stranded; BUT, only a mechanical one that can dump gas directly in your oil pan will leave you stranded to the point that an engine rebuild will be required to get you going again.

[isaac_alaska]

a failed electric fuel pump just means you tie the spare fuel jug up on the hood and shove the fuel hose in it, good to go!
got a recommendation for a good 24V pump? i can drill my own plate and just use the original pump to engine block gasket.
i'm also in the market for a good 24V vacuum pump, cause the pump that's on it right is only a fuel pump, and doesn't have the original vacuum section on it.

[Jess]

I still have the original type fuel pump but converted the wipers to 24V electric to eliminate the vacuum wipers and associated plumbing. Charles is right on about the diaphragm failure. Marine engines have a sight glass on then so you can inspect the condition of the pump by making sure there is nothing in the glass. Fuel in the crank case is the kiss of death. For the wiper motors, I used marine Wexco units, available in either 12V or 24V. They are not inexpensive but can stand up to heavy use. Wexco build many if not most wiper motors for the truck and auto industry. Along with the motors, I went with marine pantographic arms and bigger modern standard wiper blades that clear a lot more of the windows and are readily available.

How's the weather in your part of Alaska? On my way next week to do the round trip tour but since the truck and camper can't fly, won't get out to the Seward Peninsula/ Nome area this time...

Jess

[isaac_alaska]

continued wiper discussion over here: (trying to keep stuff searchable)

http://www.g741.org/PHPBB/viewtopic.php?f=3&t=7331

[isaac_alaska]

looks like FRB-15 would do the trick, but probably needs an inline fuel pressure regulator between it and the carb?

http://www.autoperformanceengineering.c ... pumps.html

[Tuko]

I ran a facet 24 volt, it's a 2"x2"cube. Currently sitting on my shop floor. No longer needed. 4-5 psi did the job well.

[Chris P]

I use a Facet 40164 fuel pump with a Holley 12-804 fuel regulator and they work great. Chose these because a number of others recommended them.

Charles, does M-Series happen to sell the plates to go over the hole in the block?

Jess, do the Wexco wipers fit into the existing hols in the M37 windshield?

[Jess]

No, you have to enlarge the holes. I had two new inner windshields and drilled them before installation. I don't have the truck here or would post a pic to show the fit. There may be other options but I couldn't find any out here. We have lots of boats so marine was easy to get locally.

Jess

[MSeriesRebuild]

[quote="Chris P"]I use a Facet 40164 fuel pump with a Holley 12-804 fuel regulator and they work great. Chose these because a number of others recommended them.

Charles, does M-Series happen to sell the plates to go over the hole in the block?

Jess, do the Wexco wipers fit into the existing hols in the M37 windshield?[/quote

We fabricate our cover plates from 3/16" plate, we keep that and lots of other metal in stock for all types of fabrication. Very simple, just cut out, drill 2 holes, make gasket, install.

[Chris P]

Thanks for the replies.

Charles, in the past I've bought things from you because you've had them fabricated in quantity. But I guess that's for things you contract out, whereas something like this you can just make one yourself whenever you need one.