Author Topic: 1959 Cadillac - Fuel Sending Unit Gasket (failure...)  (Read 846 times)

Offline Dan Eckstein

  • Posts: 181
1959 Cadillac - Fuel Sending Unit Gasket (failure...)
« on: April 17, 2017, 09:14:08 PM »
Hell All,

I am interested in hearing thoughts and maybe experiences with rubber gasket failures.  The following pictures are from a fuel sending unit which has a failed gasket.  The gasket appears to have bulged on one side and shrunk on the other.  Upon installation 6-7 years ago, everything was brand new.  Last year before storage I noticed the problem and waited till now to address it.  I always store the car with a full tank of gas.

I am trying to figure out what caused the rubber gasket to fail, and would appreciate any insights.    My concern is that it was ethanol, and that I need to find a replacement that is ethanol resistant.

Thanks in advance for all your help!
Thank you for your time,
Dan Eckstein
CLC #24850

Online The Tassie Devil(le)

  • Administrator
  • Posts: 12412
  • CLC Number: 18992
  • Name: Bruce Reynolds
Re: 1959 Cadillac - Fuel Sending Unit Gasket (failure...)
« Reply #1 on: April 17, 2017, 09:27:33 PM »
Never use rubber on anything related to petrol.

Always use Neoprene, which is available in sheets at local parts suppliers like NAPA, or marine shops.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

Offline Dan Eckstein

  • Posts: 181
Re: 1959 Cadillac - Fuel Sending Unit Gasket (failure...)
« Reply #2 on: April 24, 2017, 08:16:09 PM »
Hi Bruce,
Thanks for the info.  I went to Napa and they didn't know what I was talking about. 

All,
Any ideas of place I could order a replacement that is ethanol resistant.

Thanks again.
Thank you for your time,
Dan Eckstein
CLC #24850

Online The Tassie Devil(le)

  • Administrator
  • Posts: 12412
  • CLC Number: 18992
  • Name: Bruce Reynolds
Re: 1959 Cadillac - Fuel Sending Unit Gasket (failure...)
« Reply #3 on: April 24, 2017, 09:12:12 PM »
G'day Dan,

Sorry for the wrong information regarding NAPA.

I thought NAPA and O'Reilley stores were like our own parts places, that sell everything.   I purchased replacement headlights for my '72 Eldo from NAPA when I was in USA (had to toss out the High/Low beams when I got home so I removed them before containerising the car and gave them away)

Here, anything I want, I go to REPCO, Or Autobarn, and for odd stuff, Brieley Hose and Handling, and Websters for Bearings and fan belts.   When I tossed a fan belt on the mainland, I had to get a replacement from a lawn mower shop.

You would be surprised just what is available from the oddest of places.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

Offline dochawk

  • Posts: 627
  • Name: Richard Hawkins
Re: 1959 Cadillac - Fuel Sending Unit Gasket (failure...)
« Reply #4 on: April 25, 2017, 08:38:08 PM »
Napa could only come up with a generic sending unit for my '72 when I checked.

OTOH, autozone suggested them for belts, and they had them all in stock.

They generally have a wider in-stock than O'Reilly/Checker, autozone, pepboys.
1972 Eldorado convertible,  1997 Eldorado ETC (now awaiting parts swap from '95 donor), 1993 Fleetwood but no 1926 (yet)

Offline Brett Baird

  • Posts: 146
  • CLC Number: 17764
  • Name: B Baird
Re: 1959 Cadillac - Fuel Sending Unit Gasket (failure...)
« Reply #5 on: April 26, 2017, 05:53:51 PM »
FYI, NAPA sells a package of gasket material containing 8 x 9 sheets of  1/16" and 1/8" thick cork, and 1/32" thick rubber fiber - both materials are for sealing fuel.  Part #  Fel-Pro 3060.
B Baird
17764
'41 Fleetwood 60 S  http://bit.ly/1jwgEWm
'59 Sedan DeVille 6339 "Flat-top"  http://bit.ly/1jwgUF1
'70 Eldorado

Offline fishnjim

  • Posts: 2431
  • Name: J. Bozin
Re: 1959 Cadillac - Fuel Sending Unit Gasket (failure...)
« Reply #6 on: April 26, 2017, 09:17:47 PM »
I see two issues;
Since it's not obvious what exact material it is, it's not possible to tell what attacked it from afar.  It could've been the right material but misapplied, too loose, etc. or incorrect one.
Rubber is too generic a term.   Look up the chemical compatibility charts for gasoline and ethanol and chose the best materials.   Two sources listed neoprene as bad to good, so it's a little dependent on the manufacturer, durometer, temperature, etc.   Nitrile is typically better in this service.   Industrially, I would use teflon or viton, gives higher temperature rating.   They make special hydrocarbon resistant "rubber" for hoses and gaskets but not sure if you can obtain over the parts counter.   If it wasn't hydraulic failure, vapors may have attacked it.   Gasoline has a variety of components of varying vapor pressures, so it might be some light hydrocarbon just as well.  They can swell and permeate.  They add more lights in the winter blend, so if you fill up in the winter before storage, the gas is slightly different.   Most of the ethanol compatibility centers around the paper in the carbs and filters, old vs new fuel hose, and those need changed.   Gaskets, if properly installed won't see much service exposure except at the edges.
Since it "pulled" in, it could've been hydraulic failure, i.e. might have lasted if the tank wasn't overfull and in liquid contact, but that's a guess.   Leave some room (10% air space) for expansion and contraction, don't fill all the way.   That alone can suck a gasket out.   I know people are thinking eliminate water and such on storage, but it's worse, if the tank can't breath/vent properly with norma temperature variation.   
If you can't get a proper (recommended) sending unit gasket for this make and model, options are; use a liquid type gasket sealer that's rated for fuel.   Cut one out of a nitrile sheet, cork sheet, or other fuel rated sheet stock.   You can get foam teflon gasket rope also.   You just wrap around and overlap and cut off the excess.   You need proper material in the proper thickness and the right fastener torque to get a tight seal.

http://www.felpro-only.com/break_room_forum/showthread.php?tid=893

 

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