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Question for my fuel pump M-38
Posted: Thu Sep 19, 2013 9:18 am
by elias929
Hi
I have a fitting brass and oil seems to leak and I want to know if it's missing a hose or I put a plug.
Here this fitting
https://lh6.googleusercontent.com/-p9DI ... 59.jpg[url]
https://lh6.googleusercontent.com/-offa ... 47.jpg[url]
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Posted: Thu Sep 19, 2013 9:21 am
by wesk
The lower half of your pump is the vacuum booster pump and oil at that fitting indicates the diaphragm has failed and you are sucking oil from the engine crankcase.
Posted: Thu Sep 19, 2013 9:38 am
by elias929
Thus for to settle the problem it must be replaced!
For the fitting it is normal she is not connected on a hose!
Is it dangerous for the engine if I drive a little before change the part!
I appreciate your help!!
Thanks Wes......
Posted: Thu Sep 19, 2013 10:13 am
by wesk
Thus for to settle the problem it must be replaced!
Replace or rebuild the pump.
For the fitting it is normal she is not connected on a hose!
There are two fittings at the bottom of pump. One goes to the intake manifold and the other to the vacuum windshield wipers.
Is it dangerous for the engine if I drive a little before change the part!
You could plug it like the one to it's left but I would be concerned if the lower vacuum diaphragm is deteriorated then most likely the upper fuel diaphragm is also deteriorated. If that diaphragm fails then you will start getting fuel in your crankcase oil. I would , at this point, be safe and replace or rebuild the pump and plumb the vacuum lines correctly.

Posted: Thu Sep 19, 2013 10:35 am
by elias929
I read the link on the site
http://www.willysmjeeps.com/v2/modules. ... pic&t=2657
The best place for buy the repair kit or the rebuilt pump, it is Midwest for the parts!!
Posted: Thu Sep 19, 2013 10:44 am
by wesk
Midwest is very honest and fair with their business. He does offer rebuilt exchange pumps. If you do not wish to rebuild your pump then buy an exchange from him.
Posted: Thu Sep 19, 2013 10:59 am
by elias929
I call at midwest and he is very friendly. it is only the upper kit of disponibility or the rebuilt fuel pump. The pump is not expensive but i think rebuilt my fuel pump with the kit at (Then and Now Automotive)
http://www.maritimedragracing.com/antiq ... cellar.htm
I like to know and understand how does it work......
Thanks Wes!
You are the reference....

Posted: Thu Sep 19, 2013 11:44 am
by elias929
Is it normal the fitting with rubber hose to metal are going at the transmissioN
https://lh4.googleusercontent.com/-llks ... 065836.jpg
Posted: Thu Sep 19, 2013 12:07 pm
by wesk
That port is plugged in my photo. It is for the fording system and carries crankcase pressures when fording valves are closed to the bell housing and transmission to keep water out. On M38's with the fording system basic plumbing installed it is a solid steel tube from that port to the bell housing. Later M38s have that port vented with the same type vent fitting used in the differentials.

This is the later units without the fording vent system installed.
Pump and oil
Posted: Fri Sep 20, 2013 5:50 am
by G740
Hi guys,
The oil in the bottom of the pump does not mean the diaphragm is bad. There is one seal that keeps the oil in the upper part of the pump. It seals around the vacuum diaphragm pull stem. This seal is the problem. I would love to see a Then and Now kit. These pump parts have not been made in a long time and I wonder how they are offering a comprehensive kit and what is included. Anyone have a picture of their kit?
John
Posted: Fri Sep 20, 2013 6:24 am
by elias929
I must take the number of the pump before ordering. when i receive this kit i take the picture for you.
Posted: Fri Sep 20, 2013 7:28 am
by RICKG

Be advised there are 2 different diaphragm & pull rod types.
Research it and communicate with your supplier (I highly recommend
then and now) before ordering the kit.
Posted: Sat Sep 21, 2013 8:10 am
by elias929
Thanks!!!!
I did not remove my pump but i have the number. (4069) I will order next week....