Fuel Pump and Rebuild Kit |
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sean
Moderator Group Sponsor Member Joined: 20 July 2005 Location: North Idaho Status: Offline Points: 7388 |
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Posted: 18 Jan. 2010 at 5:44pm |
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Howard
Member Sponsor Member Joined: 17 Feb. 2006 Location: New Mexico Status: Offline Points: 976 |
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Very Cool Sean,
According to the TM9-1828A Manual, failure to hold the diaphragm, as instructed, while securing the cover screws will cause the pump to deliver too much pressure. There has been some debate about this instruction. Undoubtedly what they are referring to in your instructions included with the kit. Some of these pumps have the oil seal and spring as shown in the drawing, they were on the diaphragm shaft.
Here is a drawing from the same manual. Hope it is of some value as well. Not a good reproduction of the drawing. Sean, any help?
Edit...I removed the drawing I posted...Larry's got it below!
Thanks Larry!
Edited by Howard - 19 Jan. 2010 at 1:16am |
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Howard F Jewett
1946 CJ2A #23353 43 GPW 106505 USA #20366014 43 Bantam Trailer T3 #14844 52 M100 K1119 |
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rocketeer
Member Sponsor Member Joined: 26 June 2008 Location: Lehighton, PA Status: Offline Points: 3473 |
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Sean here's the diagram and instructions from TM9-1828A. If not appropriate to this thread let me know and I'll remove the post. Take note that when talking about the oil seals it says "If used".
Larry |
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sean
Moderator Group Sponsor Member Joined: 20 July 2005 Location: North Idaho Status: Offline Points: 7388 |
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Thanks guys. The descriptions in the TM are more detailed, but the illustration depicts oil seal parts not used in CJ-2A, could be confusing. That is a "typical" AF pump, not specific for MB or CJ-2A. The 2A Service Manuals and Parts Lists have the right illustrations. The first one I posted above (same as TM-10-1513), and this one (same as SNL G-503, MB Parts List):: As for the TM diaphragm instructions, at best confusing, at worst wrong (it might be appropriate for some other vehicle pump, but not CJ-2A). The diaphragm must be in fully flexed position before tightening the cover screws. That occurs when the rocker arm is released, allowing the spring to force the diaphragm upward, limited only by the 6 cover screws. If it's clamped w/out flex, it can't create enough pressure or flow. The written instructions in the kit: "... move the rocker arm until diaphragm is level with the flange surface. Place cover in position with screws drawn down ONLY FINGER TIGHT. Release the rocker arm, which will flex the diaphragm to the correct amount, then tighten cover screws ..." Sean |
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Howard
Member Sponsor Member Joined: 17 Feb. 2006 Location: New Mexico Status: Offline Points: 976 |
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This diaphragm installation has generated some debate in the past among collectors. Sounds like some other erorrs in the TMs...or at least some misunderstandings in interpretations. The kit instructions make sense but a pressure test would verify the actual output from the pump. FWIW, There is also some referance to testing the output pressure, valves and diaphragm function after assembly.
The TM says,
"...attaching pressure gage to pump outlet. Operate priming lever or rocker arm until gage shows 3 psi. Discontinue building up pressure and observe time required for gage pointer to drop from 3 to 2 psi. A time lapse of 5 seconds or more indicates a satisfactory pump."
Would this be a proper test? It sounds odd to me. At best it would be testing the check valves. No referance to volume. I have never performed this test to know what my fuel pumps have put out after rebuild. But my pumps have worked just fine...
Edited by Howard - 19 Jan. 2010 at 4:04pm |
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Howard F Jewett
1946 CJ2A #23353 43 GPW 106505 USA #20366014 43 Bantam Trailer T3 #14844 52 M100 K1119 |
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sean
Moderator Group Sponsor Member Joined: 20 July 2005 Location: North Idaho Status: Offline Points: 7388 |
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Howard:
ie. if it can't reach 3 PSI, there's a problem, and if it leaks down too quickly, there's a different problem. Keep pumping and it should max out at 3.5 - 4.5 PSI ("new" pump spec.)
Measure diaphragm spring force on a scale when compressed to @ .8" high (installed height). Should be around 13 lbs or slightly more. The diaphragm is @ 2.25" diameter (@ 3.8 sq-inches), 13 lbs gives you @ 3.4 PSI. Sean
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Craddman
Member Joined: 28 Aug. 2017 Location: Southern IN Status: Offline Points: 2 |
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Reviving an old thread. Newbie here. I own a 1947 CJ2A. It has been in our family since 1964 and we have had it in use that entire time; first as a personal vehicle and for the last 45 years as a utility vehicle on vacation property we own. With a little TLC it has worked well until it wouldn't start this spring after sitting over the winter. After some trouble shooting it would appear that I have a bad fuel pump. I have removed and cleaned the fuel pump but there are no markings other than a label on the glass bowl that says "Made in Canada" (I would assume not original). I assume all that is required is the diaphragm - (I will also need the mounting gasket) but I have yet to disassemble. Any ideas on where to look for a replacement diaphragm - rather than trying to find an entire new pump? The ethanol in the gas added in recent times may be wreaking havoc on older materials. Any assistance is appreciated.
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1947 CJ2A
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athawk11
Member Joined: 18 Jan. 2012 Location: Arvada,Colorado Status: Offline Points: 4151 |
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If you had the original style pump shown above, it may be worth rebuilding. If you have a glass top, it is a replacement. For the price, it may make more sense to buy a new pump. They are around $40.00 and will already have diaphragms that will hold up to the ethanol fuel mixtures.
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1- 1946 CJ2A
2- 1949 CJ3A |
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Craddman
Member Joined: 28 Aug. 2017 Location: Southern IN Status: Offline Points: 2 |
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WOW - amazingly fast response especially given the age of this thread. Thanks . It is, in fact, a glass top and now that I think about it, I'd probably replace the gasket that the glass top seats against since it seems a little brittle so given the cost of the new pump (and considering I'm not trying to keep everything original) it looks like buying new is the best route. I don't want you to do all of the work for me but since I'm here... Any ideas of where to get the new one and or a model/part # or other spec. that I'll need to get the proper pump?
Thanks again for the assistance - much appreciated.
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1947 CJ2A
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Stev
Member Sponsor Member Joined: 27 July 2016 Location: Cincinnati Status: Offline Points: 2389 |
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A little more life into this thread - What do you do if you have a historical pump and it works fine to pump gas but the rocker arm pin leaks oil down the side of the engine. What is the fix? Machine a bigger pin? Is the pin suppose to move once installed - this one shifts.
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Stev
1946 CJ2A Trail Jeep (The Saint), 1948 CJ2A Lefty Restored |
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athawk11
Member Joined: 18 Jan. 2012 Location: Arvada,Colorado Status: Offline Points: 4151 |
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Craddman, I purchased and installed this pump. It works as it should.
These are fairly common. You might even have luck at the NAPA store. Stev, I wonder if you have enough pin to peen it a bit?
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1- 1946 CJ2A
2- 1949 CJ3A |
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