Fuel Pump Rocker Arm - Bent by Design

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Dennis Vogel
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Fuel Pump Rocker Arm - Bent by Design

#1 Post by Dennis Vogel » Sun Jun 02, 2019 7:35 pm

I am rebuilding my fuel pump and discovered that this piece has a small bend at the tip. Is it designed to be that way? I believe this is referred to as the rocker arm. I can't image how it would get bent inside the pump, but it looks weird.
FuelPumpRockerArm.jpg
FuelPumpRockerArm.jpg (61.91 KiB) Viewed 387 times
1960 356 S90 Sunroof Coupe
2014 Carrera S

Dick Weiss
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Re: Fuel Pump Rocker Arm - Bent by Design

#2 Post by Dick Weiss » Sun Jun 02, 2019 10:21 pm

It should be flat, but being hardened, It's hard to believe it's bent; Possibly the pump's pushrod isn't square on the end (from a modification?) and lack of enough grease in the cavity, it forced the arm's contact to 1-side.
OR--the pivot hole in the arm is sloppy(?)
The arm doesn't look like it's shape isn't correct(?)--it's been awhile since seeing one; None in my archives.

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Ron LaDow
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Re: Fuel Pump Rocker Arm - Bent by Design

#3 Post by Ron LaDow » Mon Jun 03, 2019 12:37 am

The wear pattern tells you something is wrong:
file.jpg
file.jpg (44.05 KiB) Viewed 355 times
At "A", the wear is offset. At "B", it is offset and not normal to the axis of the part or the pivot C/L.
I don't know beans about early fuel pumps, but that wear pattern tells me you need a new part.
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SPIKE JONES
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Re: Fuel Pump Rocker Arm - Bent by Design

#4 Post by SPIKE JONES » Mon Jun 03, 2019 1:10 am

Speaking of new parts, does anyone know of a source for this piece as well as the rocker arm?
BTW, this piece on my '58 cab looks just like the one in the picture as does an aftermarket one I purchased many years ago. Both have the bend.
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Robert Vaughan
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Re: Fuel Pump Rocker Arm - Bent by Design

#5 Post by Robert Vaughan » Mon Jun 03, 2019 7:48 am

Wear pattern? That is not a wear pattern.
That is the pattern left by the shearing of the steel when it was punched out of a sheet. It is bent because the sheet steel had no strength in that direction during the punching / shearing process.
Look up fine blanking.
(typed by early morning sore head)

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Vic Skirmants
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Re: Fuel Pump Rocker Arm - Bent by Design

#6 Post by Vic Skirmants » Mon Jun 03, 2019 7:48 am

Doesn't that "bend" go into a slot in the diaphragm rod? It helps to keep it from disengaging from the slot. That's why they are ALL bent!

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Bruce Smith
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Re: Fuel Pump Rocker Arm - Bent by Design

#7 Post by Bruce Smith » Mon Jun 03, 2019 8:23 am

Vic Skirmants wrote:
Mon Jun 03, 2019 7:48 am
Doesn't that "bend" go into a slot in the diaphragm rod? It helps to keep it from disengaging from the slot. That's why they are ALL bent!
Yes
Bruce

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Dennis Vogel
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Re: Fuel Pump Rocker Arm - Bent by Design

#8 Post by Dennis Vogel » Mon Jun 03, 2019 9:58 am

Vic Skirmants wrote:
Mon Jun 03, 2019 7:48 am
Doesn't that "bend" go into a slot in the diaphragm rod? It helps to keep it from disengaging from the slot. That's why they are ALL bent!
Thanks Vic. Makes more sense now.
1960 356 S90 Sunroof Coupe
2014 Carrera S

Dick Weiss
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Re: Fuel Pump Rocker Arm - Bent by Design

#9 Post by Dick Weiss » Wed Jun 05, 2019 10:02 pm

Dennis and all,

I'll correct myself that the tip of the pump's rocker arm has a slight bend to allow the diapham's slotted tip to get 'hooked' to the the rocker arm's tip to stay engaged when slightly twisting the top 1/2 of the pump to line up to the screw holes.
Years ago, I had the pump's pivot pin almost out of it's retainment (not having the tru-arc rings) and was able to re-hook the diaphram's slotted end to the rocker arm w/o having to remove the whole pump from the engine--since I was still on the road going home; Of course, I had to remove the top 1/2 to 'hook' it--luck was w/me!!!

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