Replacing Voltage Regulator

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lovetoski

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Was running some errands today and noticed that the voltmeter was reading quite low. Made it home fine, checked voltage with my trusty multi-meter...and got 12.2 volts (truck running). Usually it's 14.2 - 14.4 running (lights and accessories off). Clearly it was running on the battery. On a hunch I grabbed a screwdriver and tapped the voltage regulator a few times...voltage rose steadily back to just over 14. Seems like the VR is going out. I have an extra alternator in my spare parts bin, so I removed the VR from the extra alternator and attempted to swap it for the malfunctioning one in the truck. But I hit a road-block...I couldn't remove the VR from the truck. The three phillips screws in the attached photo are really tight - so tight they will strip out. I have an impact driver, but when I use it, the VR moves, negating the effect. I'm not sure if the impact driver will damange the VR or the alternator - it felt like it might - so I stopped. I sprayed PB blaster carefully around the three screws and buttoned it back up for now. I'll give it another shot tomorrow.

Any other suggestions?

Or, since I "fixed" the VR by tapping on it, should I just leave it alone for now?

Thanks!
VR Replacement.webp
 
Thanks for the post. Mine is doing a similar thing, it charges normally about 60% of the time, poorly about 30, and about 10% does not charge. I carry a spare alternator and have been waiting 3 years for a 'hard' failure so I could justify swapping in the spare and finding a replacement. Let us know how yours turns out. Dan
 
Would the VR cause the voltage to be all over the board, mine goes from 12.6 to 16 and sometime it stays on 14

Sent from my iPhone using IH8MUD
 
I had similar symptoms, alternator delivering 14v then not charging. I tapped it and it resumed charging for a few weeks then quit. In my case the brushes had worn down, had them replaced and that fixed it.
 
The voltage regulator on mine went out, causing a high charge of 16+ volts and frying my battery. Sounds like your alternator may be going out- not just the VR. I'd replace it all.
 
Get the screwdriver on 'em, and lightly tap it with a hammer. That's how I'm usually able to get out screws and bolts when I can't use Kroil and there's no corrosion.
 
I don't know what it is ...but some of those small phillips head type screws / bolts that Toyta used are not the greatest. I've had the heads simply shear off and or strip without the application of that much applied force.. Tapping with a hammer works sometimes...You might want to make sure you have some replacement screws to use. A propely sized impact driver works....but you might try the correct sized screwdriver first applying only moderate force to see what happens and applying a lot of force in a downward application so that the screwdriver has less opportunity to slip.
 
A good set of JIS screw drivers will save them from striping (most of the time).

Dyno
 
Those screws can been a real pain in the ass.
I just had to drill out the two on the back plate, and Toyota no longer sells them!
Make sure you use never seize when you put the regulator back on.
 
Dynosoar said:
A good set of JIS screw drivers will save them from striping (most of the time).

Dyno
Click to expand...

It's interesting (to me) that the phillips head is designed to cam out under high torque. JIS is not. This might be why it is so hard to loosen a tight screw with a phillips screwdriver.
List of screw drives - Wikipedia, the free encyclopedia

I suppose the screw driver that comes in the Land Cruiser tool kit is JIS design.
 
2mbb said:
I suppose the screw driver that comes in the Land Cruiser tool kit is JIS design.
Click to expand...

:doh:I never thought to use that one!!
 
Driving home from skiing a couple of days ago and the VR started acting up again. Was running a bit high, then low and stayed low. A little aggravating, since I had lights, windshield wipers, fan, radio all going. Since I have a dual alternator system I flipped my marine battery switches around, and drove home using the secondary alternator/battery to run the truck. Worked fine.

Clearly, the VR on the primary alternator needed replacing. Ordered some of the JIS phillips screwdrivers...

Amazon.com: Hozan JIS-4 JIS Screwdriver Set (Ikas Exclusive): Home Improvement

They are nearby, so only took a day to arrive. They appear to be well made. Went back after the three stuck screws. No question the JIS tips fit better and tighter. Much tighter. Got two of the screws out, but took all the wrist strength I had. Could not get the third one out. The screwdriver didn't slip, I wasn't strong enough to turn it.

Took a thinky...use the impact screwdriver or put a wrench onto the new JIS screwdriver? Went with the impact screwdriver...but I broke the old VR (no biggie) plus the plastic spacer beneath it. Epoxyed the plastic spacer, installed the new VR and the alt now pumps out 14.3-14.4 volts just like it's supposed to.

Lessons learned...
1. JIS screwdrivers are worthwhile having.
2. Try not to use an impact screwdriver on the three little screws on the VR.

Here are a couple of pics...
VR Replace 1.webp
VR Replace 2.webp
 
Just broke mine (VR) trying to get it out...that plastic inside retains the nuts inside so the screw can gain purchase without spinning the nut. The plastic just isn't strong enough to hold under high torquing. My Alt. has been vacillating between 17 and 14. Has to be the VR, right? Has anyone experienced a situation where the alt's output makes it impossible for the VR to do it's job? In other words, given that the alt is throwing 17+ sometimes, is my problem definitely the VR or could it be the alt as well?
 
Trapper50cal said:
Just broke mine (VR) trying to get it out...that plastic inside retains the nuts inside so the screw can gain purchase without spinning the nut. The plastic just isn't strong enough to hold under high torquing. My Alt. has been vacillating between 17 and 14. Has to be the VR, right? Has anyone experienced a situation where the alt's output makes it impossible for the VR to do it's job? In other words, given that the alt is throwing 17+ sometimes, is my problem definitely the VR or could it be the alt as well?
Click to expand...

Trapper, I can't say on the alt, but I'd checked the inside volt gauge and compare it to the volt reading across the battery terminals while running. Mine was 16+ when the LC was running, my VR was bad.. replaced and no problems since.

I would also, say that it could be the alt and VR as a combo issue, but VR seems like the initial culprit.

Also, your battery won't like a +15 volt charge for very long as most are designed at a 14.8 max rating and may cause some problems with the battery as well.

Good Luck!

J
 
I fried 2 Optima Gel batteries when my voltage regulator went out. Finally figured out because it wasn't regulating the voltage, and it was staying at around 16-17. I replaced the whole alternator/ VR as a unit.
 
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