Battery Fill Caps blown off

[mark44004]

Hi. I just traded my 1973 Chevy El Camino for a 1972 Ford F100 Custom. Recently I seen that one of the caps and the other popped up a bit on my battery. It is a new battery. I am told to suspect the voltage regulator. But I noticed next to the starter solenoid that there is a small component which has either 3 or 4 prongs that fit into it. It is not attached to the fenderwell, even tho it has a mounting hole for a bolt, and it looks quite rusty and pitted. What is that item? Should both it and the voltage regulator be replaced? Thanks. Also, I have not had any issues starting the truck.

[motzingg]

put a voltage meter on it while its running and measure output voltage. if its not holding steady around 13.5-14v you have a problem. much better to find the problem first, rather than play musical chairs swapping parts around.

might be better off swapping out for a 3G alternator or a 1-wire chevy while you're at it.

there is also a mechanical adjustment, a tab that attaches to a spring, you can actually bend to set the bias and adjust the output voltage, i think, there is some stuff wrote about it.

[69Ford]

Hi. I just traded my 1973 Chevy El Camino for a 1972 Ford F100 Custom. Recently I seen that one of the caps and the other popped up a bit on my battery. It is a new battery. I am told to suspect the voltage regulator. But I noticed next to the starter solenoid that there is a small component which has either 3 or 4 prongs that fit into it. It is not attached to the fenderwell, even tho it has a mounting hole for a bolt, and it looks quite rusty and pitted. What is that item? Should both it and the voltage regulator be replaced? Thanks. Also, I have not had any issues starting the truck.

I do believe the item is your horn relay it goes right next to your solenoid. It should have three prongs.

[mark44004]

69 Ford, Thank you very much. My horn does work so that means it hasn't failed. But I should still change it as it's a rusty thing.

[sykanr0ng]

Two thoughts;
First, there is probably acid sprayed in the engine compartment which needs neutralized before it corrodes everything.

Second, consider replacing/upgrading the battery.

I'm a big fan of the Optima (sealed) batteries.

[68RGR]

I've been around lots of batteries of all sorts.

Most lead-acid batteries have VENT caps to allow the gases produced during charging to escape. If your caps are actually being "blown" off (or up), there almost has to be a problem with the "vent" part of the vent caps. That needs to be addressed first.

As others said, check the voltage with the engine running. Watch it over a period of 4 or 5 minutes to see what happens. If it stays within limits, try turning off the engine and leaving the headlights on for a few minutes to discharge the battery a little. Then repeat the voltage monitoring with the engine running to see what it does then. With the battery discharged, you should see a gradual climb to 14 volts or whatever voltage the regulator allows. At that point, the voltage should stabilize and remain constant as long as no additional loads are added to the system.

If you fix the vents and the voltages stay within limits, you shouldn't have any more problems with the caps. If you do, post it here.

I think you said it was a new battery. If it is really new, and the vents aren't working, you really should report that to the dealer who sold it. Could be a serious problem.

[ToughOldFord]

Your battery is overcharging. Like the others mentioned, check the voltage. Probably just the regulator, but be sure to address it. Blowing the caps is one thing, but battery explosion is on the agenda for an overcharged battery, and it is no small explosion.

As to the horn relay, I'd just bolt it back where it belongs and call it good. Unfortunately replacement parts are so hit and miss in regards to quality, (usually miss), that the old rusty parts often have a longer lifespan than the new parts.

[mark44004]

Thanks for all the info. I did purchase a new voltage regulator and drove the truck this morning about 50 miles. Caps are still on so that must have been the problem.