Fuel pump blood brother
...If the pump is tight against the housing, it is not possible to put the full length bolt in, because the housing doesn't allow for the proper angle for starting the bolt. The trick seems to have been to keep the pump about 1/4" away from the accessory case, while starting the bolts. Some sort of shims might make this easier. Pull the pump back too far, and the lever slips off the plunger. A balancing act.
It is probably a good thing that whoever designed the dang thing has probably croaked. I've worked on a lot of cars, etc., and I'm not sure I've seen a dumber setup...
Yep, what Alex said. This thing is just unbelievable.
First the decision to use hex bolts. That means you have to come in straight but you can't do that because the housing is in the way. Those bolts also make it much harder to safety wire, because the wire goes astray whilst it is in the cavity. Oh, and if the safety wire holes line up sideways you have about 1/8"clearance to the case which also greatly adds to the safety wiring challenge.
As has been said, it is critical to have the pushrod engaged with the arm when you install the pump but you can't just put the pump in position because then you can't start the bolts. The canny designer made the position where the bolts can be started almost exactly the position where the rod jumps off the arm. Probably none of this is a huge deal if you can get to the back of the engine, but it is hard when you can just get part of one arm in and don't have clearance to even operate safety wire pliers or dykes.
Anyway, I actually got the thing installed today and made two failed stabs at the safety wiring. I'll come back at that tomorrow with hemastats. The tips from this forum were a big help; in particular the round end allen wrench was a huge help.
The reason I changed the pump out is not because it failed; it is because it was working too well.
...I had five A&Ps tell me a fuel pump couldn't fail to a too-high situation, but mine did. It overflowed the carb. The fuel pressure will never go higher than what it takes to force fuel past the float valve, something around 9psi, at least on my carb...
I have been using the pump for 10 years but for the last 6 months the fuel pressure has been too high, like Bob's. For me this has only intermittently caused a problem, and only while taxiing for takeoff. The fuel pressure would go up to around 8 or 9 flooding the carb and causing very rough running. I would keep it running by fiddling with the mixture, near idle cutoff, and after the runup the pressure would be to an acceptable, but still high value, and there would be no problem until the next cold start.
Also like Bob, I asked many mechanics about this (myself, I'm not one of them mechanical guys) and none of them felt like it could really happen. If anything, an older pump should put out a lower pressure, they would say. What could I do though? All I could think of was a new pump. After I finally got it on today, I ran the airplane and it ran great. The fuel pressure was 5 PSI, which I just haven't been seeing. Even when it was within limits, it was usually around 7 or 8 on the initial start of the day.
So I don't have enough experience to say for sure the new pump solved my problem, but it looks good so far.