Leaking Fuel Pump Diaphragm?

[franken]

If it hasn't been mentioned, GM vehicles used steel lines from the mechanical pumps to carbs. Rubber lines on the pressure side bad.

[BRL]

I picture all the Holley duel feed setups with rubber lines running to them.

[BRL]

For that matter my Carter P4070 fuel pump came with brass fuel line nipples on both sides.

ETA: I'm not really too worried about a low pressure fuel pump bursting a short section of rubber fuel line but I do like the idea of flaring the tubing for a little more resistance.

ETA II: Hey I kinda like this edit to add stuff, I don't have to keep bringing this thread to the top.
To put things in perspective, my cooling system is running at least twice or maybe more pressure than my low pressure fuel system and that arrangement is nothing but rubber hoses and band clamps.

[Willshook]

It’s not about burst pressure.

Coolant does not catch fire

[BRL]

Nor does gasoline as long as it doesn't leak from a ruptured mechanical pump diaphragm or something.
Hey I drive around all day with 20 gallons of fuel behind my seat, I'm a risk taker.

[Willshook]

Originally Posted by BRL

Nor does gasoline as long as it doesn't leak from a ruptured mechanical pump diaphragm or something.

Or something. Like a loose hose clamp squirting fuel over your hot exhaust.

I said my advice would be unwelcome

Carry on

[BRL]

Originally Posted by Willshook

Or something. Like a loose hose clamp squirting fuel over your hot exhaust.

I said my advice would be unwelcome ...

Not true, your advice is welcome, just bear in mind that you can bomb proof your fuel delivery connections but a leaking diaphragm can still allow fuel to squrit onto your hot headers while you're cruising down the highway at 45mph.
Or maybe accumulate on your garage floor for days because you neglected to check in on your poor C-10's while you buzzed around town in your Telsas...you seething lowlife's!

Any advice is welcomed.

[67 twins]

Originally Posted by BRL

Not true, your advice is welcome, just bear in mind that you can bomb proof your fuel delivery connections but a leaking diaphragm can still allow fuel to squrit onto your hot headers while you're cruising down the highway at 45mph.
Or maybe accumulate on your garage floor for days because you neglected to check in on your poor C-10's while you buzzed around town in your Telsas...you seething lowlife's!

Any advice is welcomed.

If you are only doing 45 get off the highway. You don't belong there. Take the scenic route instead.

[BRL]

I was slowing down because somebody didn't take everybody else's advice and ditch the rubber hoses and worm clamps and the cab was filling with smoke.

I ran the pump to look for leaks and there were 3, both 5/16" brass fittings on the pump that I immediately replaced with the original 3/8" fittings and the before carb. bronze element filter that I screwed in wrong.
I'm replacing that with a one piece metal filter, but other than that there were no leaks and no fuel dribbling down the carburetor venturies either. 🙂

And geezer#99 was right, it sounds like I bolted a Hamilton Beach blender to my frame but I can easily compensate for that with my killer stereo volume control.

[68 TT]

Originally Posted by BRL

That is scary!

I might drive my truck every few days now that I'm retired and it's embarrassing to have to crank the engine over for 20-30 seconds every time before it finally starts using today's fuel.

So I've decided to eliminate that problem by deleting the mechanical pump and replacing it with an electric.
Yea this pump is probably overkill but those selinoid pumps sound like a friggin' jackhammer.

Thank you for the reply and Happy New Year!

I ran that Carter electric pump for years on my Chevelle. It works great and is pretty quiet. I made it quieter by mounting it on top of and through a set of rubber shock mount bushings so there was no metal to metal contact on the bracket to the frame or the mount bolts to the bracket.

[68 TT]

My cousin had a fuel pump diaphragm leak into his engine while it was running and fill up his crank case. It worked just enough that the engine still ran but still leaked fuel into the engine. It diluted the oil down so much that it trashed the bearings in no time flat. We ended up having to put a different crank and cam into it because the journals and lobes were so torn up. This happened in one days commute to work on the highway about 30 miles round trip.

[BRL]

Originally Posted by 68 TT

I ran that Carter electric pump for years on my Chevelle. It works great and is pretty quiet...

I fired up the engine for the first time a little while ago with the new pump and it was so quiet I had to physically get under the truck and touch it to make sure it was still working.
It was but I quickly discovered that I need to fabricate a tin heat shield because of the close proximity of the exhaust pipe.
Other than that it ran great and fired right up after sitting for so long.

[BRL]

Originally Posted by 68 TT

My cousin had a fuel pump diaphragm leak into his engine while it was running and fill up his crank case...

That is sad, other than a leaking diaphragm causing a car fire I can't think of a worse case scenario.

[BRL]

Fuel pump function check.
This counts as an early Sideways Saturday shot.

[lil hoodlum]

Looking good, nice rig!

[BRL]

Thank you, I always appreciate compliments from fellow 67-72 Chevy truck forum members.
I could barely perceive a slight humming sound from the pump when I was stopped at a stop sign with the truck in gear, (yes I do stop for those things) and that was with the stereo off. (a rare occurrence)
Very pleased with the installation and twisting around under the truck for days has limbered up my joints to the point of patting myself on the back has become much easier now.

[Willshook]

Originally Posted by BRL

And geezer#99 was right, it sounds like I bolted a Hamilton Beach blender to my frame but I can easily compensate for that with my killer stereo volume control.

It’s not bolted directly to the frame, right?

Needs to have shock mounts to dampen movement or it’ll crack the housing at some point. Side benefit is reduced noise.

[BRL]

The mount is bolted directly to the frame but the pump itself comes with
insulating rubber grommets for the mounting studs so harmful vibration isn't a problem.

The pump did surprise me by how quiet it is with the engine running, and I have a very quiet exhaust note.

And as a friend pointed out to me yesterday, even that annoying noise from those jackhammer sounding selinoid pumps we have disappears after we start our cars.

Thank you for commenting.

[BRL]

Oh yea, quick update.

I made a heatshield from a scrap overhead incandescent light fixture and replaced the two piece fuel filter with a one piece.
Engine starts right up now after sitting for days and is doing great so far after a few hundred miles of use.

Mission accomplished.

[BRL]

Originally Posted by geezer#99

That’s sure a bunch of clamps.
Did you at least single flare the metal lines?

Just to give you guys an update, the truck does start right up now after sitting for a rather long period of time, I just let the electric pump run for 15-20 seconds before trying to start it, fires right up.
And I got a flairing tool, I just need a little flair on the end of the metal lines to give the rubber hoses a bit more grip, nothing too fancy.

[LockDoc]

Originally Posted by BRL

Just to give you guys an update, the truck does start right up now after sitting for a rather long period of time, I just let the electric pump run for 15-20 seconds before trying to start it, fires right up.
And I got a flairing tool, I just need a little flair on the end of the metal lines to give the rubber hoses a bit more grip, nothing too fancy.

Good job. Even with all of the flack you received over the project....

[BRL]

Originally Posted by LockDoc

Good job. Even with all of the flack you received over the project....

Thanks for the kind words LockDoc, I got enough self-praise to cover a bit of criticism from these...guys.