my voltage gauge in my truck reads 12 volts until i hit about 1500rpms and then it falls and begins to bounce, and if i have my lights on it causes my fog and head lights to do this strobing effect, along with it my dash lights, however when i idle down the srobing stops, and the more stuff i turn on the slower the strobing gets, two questions, what is it thats doing that, andhow long can i continue to drive my truck like this, im on a teenagers budjet and cant afford a alternator right now, but i am smart enough to rebuild it, afer all i build engines, so how hard could an alternator be? i apreciate any help i can get, i herd that i might be my brusshes in the alternator.

88 F-150 4x4 Supercab
Mustang 302, MSD, Bassani stainless 4" exhaust and headers, Comp cam, K&N cold air induction, balanced, Blueprinted 380b.h.p.

 

Well you should have at least 13.5 volts when the truck is running. So that said it sounds like the voltage regulator is dying, or the alternator belt is slipping due to wear or just being loose.
I think the last rebuild kit I bought was about $20 Cdn, but that was a Chevy one I rebuilt for a friend. I cant remember the last Ford one I did. Boy is the memory ever going
Anyway the kits come with instructions and arent too difficult to complete. Unless the alternator armature is bad. Then you might as well buy a new alternator.
Does your truck have the integral voltage regulator, or is it separate from the alternator. I have never owned one of those "new fangled" 80's vehicles, way too new for me

Sparky

 

[updated:LAST EDITED ON 28-Feb-02 AT 00:44 AM (EST)]my truck has the internal voltager regulator, and i have a 2 inch serpentine belt with underdrive pullys, so i doubt that its slipping, the strobing is consistant to the amount of draw i put on the system, the less the draw the more the strobing wih minimal voltage drop, the more the draw, the more drastic te drop in voltage, and the strobing sems to solw down, its got me confused, i love my truck, but sometimes it make me mader then any woman could!

88 F-150 4x4 Supercab
Mustang roller 302, MSD, Bassani stainless 4" exhaust and headers, Comp roller cam, K&N cold air induction,MSD heli-core wires, aluminum race radiator,MSD Blaster coil,comp roller rockers, balanced, Blueprinted 390b.h.p.

1978 F-250 460 camper special super cab long box, air bags, 3"exhaust,towing package,2 ton capacity, all original, cherry, and a 78 conestoga camper to go with it

 

Replace the V.reg or take the whole alternator to an automotive parts place and have them test it for you.
It's free at most places.

Dennis https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=1733&.jpg



Please Don't Ask Me Any Tough Questions,
"I'm Saving My Memory For When I Develop Alzheimer's"


78 F-150 429CJ,Silver, Explorer Pkg.
641/2-Mustang 260,Pre-World's Fair Car.
64-Fairlane500 S/C waiting for a 390-4spd.
68-Mustang 289-Sunlit Gold 80,892Mi
78-Buick LeSabre 403 4V
84 Volvo DL Wagon

 

Well check the battery positive and negative wires for corrosion and tightness, especially the ground on the block. If all is well I would vote for the regulator being on its last legs.

Sparky

ps
A 78 F250 Camper Special now that is closer to my era

 

Well it's not hard to rebuild your alternator,just not cheap to buy the equipment to test the components right, but if you want to throw some parts in it to see if you can get it to work, this unit is a 2G alternator on you truck, replace the Rectifier and the brush set, but I bet when you take the unit apart you will find the rotor sliprings are worn down with a deep groove in them and possibly the rotor sliprings are not true round anymore, so also get a rotor assembly to boot. Remove the rectifier and stator assembly as a complete unit by going in with a torx head screwdriver or bit and remove the rectifier unit. Now pull apart the stator from the rectifier, Clean the stator leads real good, install your new rectifier on the stator leads and have a good hot solder gun available, solder this time the stator leads to the recifier using solder with silver in it, (takes the temperature better) keep the heat off the diode pack though, you can wipe it right out by applying to much heat, also make sure your rectifier is made up of a 70 amp diode pack assembly, or you will be doing it again, Ford has to many voltage spikes in there system and blows lower rated diode packs out. Make sure you use heat sink compound on the backside of the new rectifier also or you will be doing it again real soon. Put it all together and see what happens, or what I would recommend, take it to an Auto Electric rebuilder and have it fixed, Auto Parts houses can test for free, but have absolutely no knowledge on what makes that thing work. Make sure you state to them though your on a shoe string budget, most of them will work with you. Hope this helps, Electric1

 

Good news fellas, my pop loaned me the money for a new alternator, we paied 85 bucks for a factory replacement one at NAPA and it cam with a 3 year warenty, by then i will have fog lights and will need a bigger alt. anyways, i apprciate all the good information you guys have given me, i have certanly learned more about alternators, thanks alot
fordmanboss302

88 F-150 4x4 Supercab
Mustang roller 302, MSD, Bassani stainless 4" exhaust and headers, Comp roller cam, K&N cold air induction,MSD heli-core wires, aluminum race radiator,MSD Blaster coil,comp roller rockers, balanced, Blueprinted 390b.h.p.

1978 F-250 460 camper special super cab long box, air bags, 3"exhaust,towing package,2 ton capacity, all original, cherry, and a 78 conestoga camper to go with it

 

Do you pay cash or did you "Charge it"?

Dennis https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=1733&.jpg



Please Don't Ask Me Any Tough Questions,
"I'm Saving My Memory For When I Develop Alzheimer's"


78 F-150 429CJ,Silver, Explorer Pkg.
641/2-Mustang 260,Pre-World's Fair Car.
64-Fairlane500 S/C waiting for a 390-4spd.
68-Mustang 289-Sunlit Gold 80,892Mi
78-Buick LeSabre 403 4V
84 Volvo DL Wagon

 

i paied cash for it,

88 F-150 4x4 Supercab
Mustang roller 302, MSD, Bassani stainless 4" exhaust and headers, Comp roller cam, K&N cold air induction,MSD heli-core wires, aluminum race radiator,MSD Blaster coil,comp roller rockers, balanced, Blueprinted 390b.h.p.

1978 F-250 460 camper special super cab long box, air bags, 3"exhaust,towing package,2 ton capacity, all original, cherry, and a 78 conestoga camper to go with it

 

i paied cash

88 F-150 4x4 Supercab
Mustang roller 302, MSD, Bassani stainless 4" exhaust and headers, Comp roller cam, K&N cold air induction,MSD heli-core wires, aluminum race radiator,MSD Blaster coil,comp roller rockers, balanced, Blueprinted 390b.h.p.

1978 F-250 460 camper special super cab long box, air bags, 3"exhaust,towing package,2 ton capacity, all original, cherry, and a 78 conestoga camper to go with it