56 fuel pump push rod

[CadillacRob]

Been working very hard trying to get the 56 to come back from the dead and idle.

LONG story short, I found my fuel pump push rod wasn't moving.  It was pitted in some spots, and in fact, slightly bent.  I'm hoping the bend wasnt from me, as I lightly hammered it down when it was stuck in the up position.  Lubed it up and it came out.  Rolling it on the table I could tell it was infact slightly bent. 

I have a new one on the way from Kanter, but I wonder, how do these things bend?  Theyre thick steel rod.  I have heard of improper fuel pump installation, but I just cant imagine that'd be the case without damaging the pump itself.  The "arm" was placed over the top of the rod and I bolted the pump in with its gasket and some sealant.

Anywho, I'm really hoping this allows the car to idle.  It keeps starting and then running shaky for about 2-3 seconds and dying.  I'm sure I have several things going on as she hasn't seen the road since 1991. 

[James Landi]

My 56 fuel pump REQUIRED grease be packed in the hollow of the pump where the arm sticks out and receives the vertical push from the cam shaft.  I vividly recall replacing a pump with a new one only to have it fail on the NJ Turnpike in morning traffic. I was convinced that since the pump was only a few months old, that the cam follower had to be worn--- NOT SO! the pivot pin on the pump arm was prematurely worn do to lack of lube, so there was not enough "throw" from the cam push rod to take up the wear slack on the new pump.  There is no lube for these associated fuel pump mechanical parts, and the idea that the pump's internal housing had to be packed with wheel bearing grease seems entirely nutso.  If the cam shaft is worn flat because the cam follower was rusted and bent, then you'll need to install a small, low pressure electric pump.  You may find this "work-around" much more convenient given the physical conditions of the cam follower and what may be an entirely flatten cam lobe on the cam shaft--.James

[CadillacRob]

Thanks james.  i just sanded and lubed up the push rod and had my wife crank the car while I watched it.  It goes up and down slowly, maybe 1/2" or less.

[James Landi]

It's been a long time, but I do recall that the vertical lift on the cam follower is rather slight--- HOWEVER, that's because the geometry of the lever in the pump CAN'T travel very far and does not in order to pump.   So: if the pump works (by hand--- you push the lever on the pump and gas squirts... and your cam follower is rising and falling, then the problem I described may be the major issue--- the pivot point on the pump lever may have too much wear for the cam follower to effect a sufficient upward push--

[CadillacRob]

Well, I got the new push rod from Kanter and it doesnt fit 

In my digital calipers the original measures about .433 and the new one is about .438/.439. 

I tried brushing out the hole with a cylindrical brush thinking maybe some sludge or something was in the way, and I oiled the hole and rod.  Nothing.  It goes about half way if I twist it but then stops and gets stuck, and hard to pull back out.

Original almost drops in.

How frustrating you spend $30 on a rod and it doesnt fit.

[Jay Friedman]

I suggest you try to take it to a machine shop who might be able to reduce it to .433, either on a lathe or more likely on a cylindrical grinder. 

[CadillacRob]

I might have to.....

If its a reasonable cost like 5-10 bucks I will.  But Kanter should be better than that.  I shouldnt have to machine a brand new part.  $30 for a pushrod that doesnt fit.

[James Landi]

As I mentioned, you may find that the problem exists not in the cam follower but in the pivot arm wear on the fuel pump itself.  THere should be no looseness in the arm and the pump action... i.e. NO LASH.   James

[CadillacRob]

The fuel pump is brand new.  I put the original pump pushrod back in lastnight and it operated the pump fine this time (I guess because I cleaned it up so much and re-oiled). But it is still slightly bent and has some corosion, which is why I want to replace it.  The brand new one from kanter wont fit down the hole.  Its 5 thousandths too wide.

[James Landi]

THe simple "work around" is a low pressure electric gasoline fuel pump that electrically operates in conjunction with an oil pressure switch  (engine runs, oil pressure actuates the fuel pump's electrical connection to ground).  Save the mechanical fuel pump for another day.

[CadillacRob]

Eh.  Im not really into adding something new because a parts supplier cant get a pushrod right.  Cheap.  Now if my cam was messed up then that'd be another issue.  But its not.  Kanter has given me the run around for over a week now.  I'll be sure to make them take the return and refund me tomorrow.

[CadillacRob]

Still havent resolved the issue....

A great member here J Gomez notified me of an Airtex pushrod NOS pr1048 measuring .436 and fitting well, and his original measuring .434.  I mentioned that to the customer service manager at Kanter and he told me they've ordered some reproductions of that Airtex rod to see how they measure out.  He did tell me he's sold 26 of their current version this year without any issue.  Hard to believe Im the only guy who has an issue.

I made a little video showing whats going on for those who care to see..

https://www.youtube.com/watch?v=zBxvmGpRt5Y

[J. Gomez]

Rob,

As the old say goes “a picture/video is worth 1000 words..!” 

Just for my personal curiosity, have you try flipping the original rod around and see if it fits?

I’m not sure what could be the cause in your case that the new rod would not fit correctly. 

Wild guess;

Corrosion on either of the two holes blocking the path 
Top and bottom holes may be slightly off round or off center 

If may be an easy fix by buffing the holes with a high grain 800-1000 sanding.

Again if I may suggest, if you have a drill bit with same or close diameter of the old rod and see if it can be slide as easily as the rod does just to validate.

In my case both the old and new slight in with no effort.

Best luck..!

[Dan LeBlanc]

These might be worth a shot.

Package says up to 1953 however, MPL calls for the same rod from 1949-1962 (Part # 3508895).

http://www.ebay.com/itm/Lot-of-4-New-Fuel-Pump-Push-Rods-3508895-1949-1950-1951-1952-1953-Cadillac-/371717886100?hash=item568c1cd094:g:7mQAAOSwaB5XvJMH&vxp=mtr

Or these:

http://www.ebay.com/itm/Lot-of-4-New-Fuel-Pump-Push-Rods-PR1050-1949-1950-1951-1952-1953-Cadillac-/361701993368?hash=item54371e6b98:g:WRYAAOSw6n5XvbIK&vxp=mtr

Looks like they'd polish out nicely with some crocus cloth.

[Jay Friedman]

For whatever it's worth, I have 2 NORS spare rods made by the Master Service Parts Co., both of which measure .4355 with my micrometer; that is, halfway between .435 and 436.  A third one is in my '49's motor,  which went in easily and works perfectly.

[Glen]

Just for fun I checked the shop manuals I have.  Interesting results.   Proves my point the parts book is not a good source of information regarding the originality of parts.  See the clips below. 

[Jay Friedman]

Until Glen posted the info from his MPL, I didn't realize there was a difference between the 49-53 and the 54 and later rods.  Given that there is a difference, and if a 49-53 rod's diameter is .435 or .436 like my 49's, would one possibility be that the 54 and later hole in the block and the rod for it is 2 or 3 thousandths narrower?  So, if the vendor is unaware of this difference and sent you a 49-53 rod, this might explain the problem.

[CadillacRob]

Guys an update!

Kanter - although they told me they sold 25 of their fuel pump push rods this year alone and I was the ONLY guy who complained about it.......and that their stuff matches their engine blueprints, they ordered an OEM one just for their own research purposes, and to test on a caddy they had in the shop.  Sure enough the OEM was smaller, fit correctly, and theirs did not.

I'll hand it to them for chasing the problem down, and will be sending me a good one now.  But, it took basically a month and a thousand phone calls.

[Bob Hoffmann CLC#96]

It's really a PITA to have to educate these repro vendors. Most of the time they have bad info & who knows where they get samples to copy. And just remember... ONE size fits ALL!
Bob

[savemy67]

Hello Rob,

Thanks for being the squeaky wheel!  You were probably Kanter's only problem because you were the only customer who complained.  Good for you.  And now, the vendor has been enlightened, to the future benefit of all.  Well done.

Christopher Winter