I had a recent post about having acquired some 40083 fuel pumps. Several have opened the post but no one has responded, probably because the questions I asked were fairly detailed and arcane. But on the 4th pump I said I was going to tear it down and rebuild it for my car and I "speculated" that it had been opened up before for inspection and put back together incorrectly. Well that was likely a good guess.
When I removed the main body form the cast top the diaphragm spring pushed the body away because the diaphragm stem was not connected to the rocker arm link. This pump has(had) the original rocker arm pivot pin in place so I'm wondering how the stem and link became disconnected without diassembly. Has anyone ever seen this type of failure before and can you tell me if there is some bigger issue I'm not seeing as a result (like an internal boss broken off in the cast cover or some such)? If not I'm going to go ahead with the rebuild like I didn't know this. Fifty years ago when I was replacing pumps on street cars the typical failure was a ruptured diaphragm and fuel leaking out.
Secondly, and if I don't get a simple response I'll probably just email Joe C. directly. In his Restorer article he made a big deal of getting the diaphragm installed correctly on the original stem (to ensure correct pump output pressure) but in his picture #10 in the article (Vol. 37 Summer 2010) it looks to me like the stem has a massive shoulder on it to locate the diaphragm parts against, so I don't see how you could get them out of position. The parts I took out today look just like his article although I haven't disassembled the diaphragm yet. What am I not seeing?
Thirdly, and this is not a question, just passing on my method if anyone is intrested. In his article Joe talked about saving the original pivot arm pin by squeezing it and t******* it with a Dremel Tool to get it out. I took a different approach. I used a small cold chisel to cut the washer under the crimp thus removing the washer (it was soft steel). After that the pin just came out without modification. I'll have to squeeze it down before replating and installation but this was a simple removal (may not work on every pump depending on how severe the crimp is) and I should get a good re-install. The downside of this was that I learned that the magnesium top is VERY soft and I did a little damage to it with the chisel. If I do this again I'll try to put a utility knife blade or something under the washer to protect the casting.
When I removed the main body form the cast top the diaphragm spring pushed the body away because the diaphragm stem was not connected to the rocker arm link. This pump has(had) the original rocker arm pivot pin in place so I'm wondering how the stem and link became disconnected without diassembly. Has anyone ever seen this type of failure before and can you tell me if there is some bigger issue I'm not seeing as a result (like an internal boss broken off in the cast cover or some such)? If not I'm going to go ahead with the rebuild like I didn't know this. Fifty years ago when I was replacing pumps on street cars the typical failure was a ruptured diaphragm and fuel leaking out.
Secondly, and if I don't get a simple response I'll probably just email Joe C. directly. In his Restorer article he made a big deal of getting the diaphragm installed correctly on the original stem (to ensure correct pump output pressure) but in his picture #10 in the article (Vol. 37 Summer 2010) it looks to me like the stem has a massive shoulder on it to locate the diaphragm parts against, so I don't see how you could get them out of position. The parts I took out today look just like his article although I haven't disassembled the diaphragm yet. What am I not seeing?
Thirdly, and this is not a question, just passing on my method if anyone is intrested. In his article Joe talked about saving the original pivot arm pin by squeezing it and t******* it with a Dremel Tool to get it out. I took a different approach. I used a small cold chisel to cut the washer under the crimp thus removing the washer (it was soft steel). After that the pin just came out without modification. I'll have to squeeze it down before replating and installation but this was a simple removal (may not work on every pump depending on how severe the crimp is) and I should get a good re-install. The downside of this was that I learned that the magnesium top is VERY soft and I did a little damage to it with the chisel. If I do this again I'll try to put a utility knife blade or something under the washer to protect the casting.
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