Vacuum Leak Vibration

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Vacuum Leak Vibration

Post by mjabbasi »

Hello, while my '62 has been giving me trouble free enjoyment for years now, little issues keep cropping up which I'm identifying and addressing. However this recent one has me a little stumped.

After the brake booster rebuild, I had some electrical relays replaced which drastically improved both the headlights and interior lights and the car was performing flawlessly, smooth, silent and tight like it should be when all off a sudden this vibration started with the engine. While the car still drives fine while parked in idle the vibration causes the open doors to slightly shake up and down and I can feel the engine vibrate and run a bit rough when revving it. The biggest clue that this could be a vacuum leak is the door locks, they have stopped working. We checked the vacuum points under the drivers side of the dash and some of the thin hoses which were a bit loose were replaced yet the vibration continues. Checked the other end of the vacuum system by removing the drivers side fender splash shield and all was normal there. However despite this, I carried on with my other pending jobs on the car.

Today along with an oil change, I replaced all 8 plugs and also put in new plug wires (the previous ones were 20 years old so I figured it was time to replace them) in the hope this might confirm the vibration is not plug/plug wire related and sure enough the vibration is still there and the same. I also replaced the instrument voltage regulator (behind the clock) and at least now my fuel gauge needle doesn't wave back and forth any more. So despite all these little upgrades and maintenance items, this vibration continues and the door locks are out of commission. The vacuum trunk release works so the 2 don't seem to be connected but I'm safely guessing now that this vibration and the door locks not working are connected to each other.

There is no simplified diagram in the manual showing this vacuum system to the door locks and was wondering if anyone here has experienced anything similar. Where should I check next? Should we have another go under the dash? Could it be possible that while inspecting the vacuum hoses under there one or two were accidentally not replaced in the correct vacuum port? If this is indeed related to the door locks, that vacuum port under the dash seems to be the only place one can look unless I'm overlooking something?
Moin Abbasi
1961 T-Bird Convertible (Montecarlo Red)
1962 LC Sedan (Nocturne Blue)
1963 LC Convertible (Premier Yellow)
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