The MGA With An Attitude
The Magic BANJO BOLT (February 2013)
I must lead a charmed life.
One night after dark, with begining of a light snow, my MGA and I were picking up parts to fix another vehicle, when a couple miles from home it started to run terribly bad, like it was running on two cylinders with very little power. I was just exiting a parking lot from a parts store onto a main street with traffic when this happened, so I took the first opportunity for a casual exit into a car wash with some lighting to have a look under the bonnet. It was spilling fuel from the rear carburetor, which I thought at the time must be an overflowing float valve. Being cold and starting to snow, I figured it best to drive it home to a warm shop rather than trying to work on it outdoors. I did make it home, but just on pulling into the garage I noticed the fuel gauge looked like it had dropped a few gallons of fuel, which seemed like a bit much for such a short time. It turned out that the rear carb had lost the banjo bolt that holds the float chamber to the throttle body, the float chamber was hanging on the fuel hoses, and lots of fuel was flowing from the bottom of the float chamber as fast as it could run through the open float valve.
I had need for the car to be drivable, so I got my daughter with her car to take me back to the parts store where all this started, and proceeded to look for the lost banjo bolt. It was not in the parking lot, not in the street entering or leaving, so I proceeded to walk on the side searching in the street. I walked slowly a couple of blocks as far as the car wash, but didn't find the bolt. We then drove the car very slowly following the route I took going home with the MGA, searching the street for the lost bolt. I was sort of hoping maybe it had caught on the car chassis somehow and maybe dropped off somewhere farther along, but we didn't find it anywhere. Considering the part was permanently lost, I ordered a new banjo bolt and tried to "get over it". This is not like my MGA to just fall apart like that.
While it was out of commission I took it as a good opportunity to change a worn RH tie rod end, which I did. On the jack, wheel off, swap the ball end, wheel back on, back on the floor, and realign the toe in, no big deal really.
A day or so later I needed the MG to run a coupe of errands, so I decided to make it minimally serviceable. I disconnect both fuel hoses, removed the banjo bolt from the front carb and used it to reattach the rear float chamber. Then I installed the front fuel hose on the rear carb and connected it to the fuel supply pipe. Finally I loosened one clamp on the throttle shaft between the carbs, closed the butterfly on the front carb and turned up the idle screw on the rear carb. The whole procedure took 20 minutes. Runing it on one carburetor is actually standard practice as part of my tune up procedure when I want to adjust fuel mixture. It works because of the balance tube in the intake manifold, and it is one of those Grapes Of Wrath repairs you can do in an emergency. When I started the engine and adjusted idle speed it ran quite well on one carb, keeping in mind that you only get half throttle when it's floored, and it doesn't want to run much past 4000 rpm with a load.
Before I go driving it around town I was going to check and tighten the fuel system fasteners when I dropped a wrench socket on the floor under the car. When I looked under the car the missing banjo bolt was lying on the floor a few inches from the wrench socket. Apparently the banjo bolt had hitched a ride somewhere on the chassis, and it hung on long enough to get home, then fell off (or perhaps jumped off) when I was doing the tie rod repair. Good for a grin. I then took 15 minutes to reattach the front float chamber (with new seals), swap the fuel hoses back, balance the carbs, tighten the clamp on the throttle shaft, and reset idle speed.
Today the new banjo bolt arrived in the post. I think I'm going to frame it.