A Troubled Season for the ‘58 Eldorado
Last year I didn’t find the time to drive my ‘58 Eldorado, so I promised myself that this season would be different. The car had been parked in my garage for more than a year, and I wanted to wake it up gently after its long slumber.
Waking Her Up Gently
Cars like this are hard to start after long storage, because all the fuel evaporates from the fuel pump and the carburetor. That’s why I always disconnect the fuel line at the pump, attach a rubber hose with a small funnel on the other end, and fill the system with fuel until it can’t take any more. After that, the engine fires up right away.
This time it worked perfectly. The car ran like a champ, and I drove it out of the garage to let it idle for a short while. Then, out of nowhere, it died and wouldn’t restart. After a few more attempts it finally caught again, but it only ran badly, and only while I kept the revs up. As soon as I lifted my foot off the pedal, it died.
Rebuilding the Center Carburetor
I’d had the same problem years ago: a clogged fuel passage caused by old fuel that had been stored for too long. It turned out the center carburetor needed another rebuild. This time I wanted to do it properly and thoroughly, so I ordered a rebuild kit and invested in an ultrasonic cleaner, which will surely come in handy for other projects too.
With the shop manual at my side, I completely disassembled the carburetor and let all the parts soak in the ultrasonic bath for about an hour. I also cleaned every passage with tiny brushes and blew everything out with compressed air.
There are two differently sized check balls inside the carb, and I found a wrong-sized one stuck in place. It took a while to get it out, and I eventually had to apply heat to the back of the housing. I also had to replace the acceleration pump during the rebuild as the silicon gasket was ripped. Once everything was clean, I reassembled the carburetor with new gaskets and installed it on the car. The shop I had used in the past had installed copper fuel lines when it rebuilt the carburetor 20 years ago and I always hated them for the looks. So now I ordered the correct steel lines and installed them.
A Bent Rod and a Lucky Find
Afterwards the car ran beautifully during normal driving, but it stalled on full-throttle runs once the other two carbs kicked in, though it always started again immediately. While adjusting the linkage, I misread the shop manual and accidentally bent one of the rods, and I couldn’t bend it back into shape.
I searched the internet for days for a replacement and got lucky: I found a man who builds tri-carb hot rod setups. Chevrolet used the same rod on some of its models, and he had a used one to sell me.
Stranded with the Family: Vapor Lock
In the meantime I kept driving, and then the car died again while I was out with my family. It seemed to happen only when the car was very hot and idling, which pointed to vapor lock. When I added cool fuel to the fuel pump, it started again. I suspected a weak pump and took it completely apart, only to find nothing wrong with it.
The Missing Prong on the Hot Idle Valve
I kept searching for the cause. On top of the carburetor sits a hot idle valve, which should open whenever you lift off the gas and the car idles, so that hot fuel vapors can escape from the carb. On my car, the prong that opens this valve was missing, so the valve always stayed shut and the vapors had nowhere to go.
Once again I found the part with a hot rod builder. It took a while to arrive, and by then the car had already gone into winter hibernation, so I couldn’t test whether the problem is solved. I’ll find out next summer. One more thing I did before I put the car into storage again was to flush the brake system with new Dot 3 brake fluid.
Trust Issues and Next Steps
The car also needs new rear mufflers, as the old ones have rusted through from the inside. I really want to drive this Eldorado more often, but it has left me stranded three times this season, and my trust in it has taken a hit. Luckily, I always had my tools with me and was able to get it running again and make it home under its own power.

Inside my garage

The center carb removed

Lots of fuel sludge when I opened it up. Thought it was rust, but it wasn't.

Inside the bowl

Check ball underneath the acceleration pump

Stuck check ball

Inside the cleaner

Soaking in cleaner

Clean again

The acceleration pump before

Reassembled center carb


Back in the car with new fuel lines

Disassemble fuel pump

Adjusting the vacuum switch

Some details from the shop manual

Some details from the shop manual


Some details from the shop manual


Some details from the shop manual


Some details from the shop manual


Some details from the shop manual

The new idle vent valve in place.

Tags:Carburetor, Tri-Carb, Fuel Pump