Wrong Alternator (1 Viewer)

[C6H12O6]

I've been going back and forth looking for alternators and couldn't figure out why my alternator didn't look quite like the replacements I'm seeing out there. Turns out, I have a late-70s Celica/Corolla/Corona alternator (27020-33012). Still 40 amps, but the plug is in the wrong spot and it is dead anyway.

Two questions, since I have to replace it anyway:

1. What are people liking for rebuilds? Bosch sounds good online and I usually have good luck with them, but not available in town. If I'm going to order one anyway, any other rebuild brands to consider?

2. Everywhere I look (online and LPS), rebuilders list a mix of 40A, 45A, 50A and 55A options. I'm thinking the 40/45A are the same part. Were the Toyota 55A alternators (27020-60040) really optional in 1974? If they were, I can't believe they did much to the rest of the truck. From everything I can find, there is only one regulator part number and the dash ammeter didn't change. I'm stumped.

I'd love more amperage if I can safely run the 55A in the stock DS location of my truck without smoking anything else. Money is about even between both. No interest in rewiring everything at the moment or putting in an internally regulated alternator unless it's virtually plug-and-play, which it sounds like it is not.

 

[C6H12O6]

Current alternator:

 

[C6H12O6]

Toyota 55A alternator:

 

[mrboatman]

You might try Alternator | CarParts
Or https://www.rockauto.com/en/catalog...276343,electrical,alternator+/+generator,2412
JP

 

[C6H12O6]

Yeah, Rock Auto has the Bosch reman for half the price of my local Napa. That's where I'm leaning if I go with the 40A standard replacement.

 

[mrboatman]

I just ordered one from rock auto and should get it on Friday.
JP

 

[hobbes]

In post #2, take note of the top eye for the bolt being at 1 o’clock. I got one from my local parts store and it had the eye at 12 o’clock. That did not fit on my 1974 setup. I notice that issue in some of the Rock Auto photos.

 

[C6H12O6]

Yes. I've seen that, too. I think the clock position of the plug is less of a big deal. You're correct—with the double mounting tabs in the down (6:00) position, the plug should be at 10:00 and the other single tab should be at 1:00.

 

[shelfboy1]

some mount on the left and some on the right they use the top bolt in different positions dont remember whats what any more

 

[65swb45]

In post #2, take note of the top eye for the bolt being at 1 o’clock. I got one from my local parts store and it had the eye at 12 o’clock. That did not fit on my 1974 setup. I notice that issue in some of the Rock Auto photos.

/this\ The 12 o clock 6 o clock variety will barely fit the F engine adjuster bracket, and will not have an adequate range of motion for adjustment as the belt slackens.

And big box stores often ship alternators with GM pulleys on them. Which is why some people spend a little more and buy one from a trusted MUD vendor who knows these things.

 

[73FJ40]

/this\ The 12 o clock 6 o clock variety will barely fit the F engine adjuster bracket, and will not have an adequate range of motion for adjustment as the belt slackens.

And big box stores often ship alternators with GM pulleys on them. Which is why some people spend a little more and buy one from a trusted MUD vendor who knows these things.

Well said. OEM Toyota alternators come in many versions. Note that my F engine has the alternator low on the driver's side, where later model 2F appear to have moved it to high up on the passenger side.

Alternator Questions

 

[C6H12O6]

Thanks, guys. Still curious about the 55A alternator. I was looking at Mark's site and even he shows a 55A option for the the early-74 trucks. I don't want to rewire everything to avoid blowing my 30A ammeter, but the 50A ammeter gauges on the dash cluster didn't start until later. If this is just a drop-in swap, I'll go with the 55A early alternator. If not, I'll just stick with the stock 40A unit.

 

[hobbes]

In my attempt, the 55 amp had the bolt ear at 12 o’clock spite of the picture showing otherwise. They didn’t have a 40 amp available, so I don’t know if that had any bearing.

 

[73FJ40]

Thanks, guys. Still curious about the 55A alternator. I was looking at Mark's site and even he shows a 55A option for the the early-74 trucks. I don't want to rewire everything to avoid blowing my 30A ammeter, but the 50A ammeter gauges on the dash cluster didn't start until later. If this is just a drop-in swap, I'll go with the 55A early alternator. If not, I'll just stick with the stock 40A unit.

Your best bet is to call Mark and get exactly what you need from an experienced expert!

 

[C6H12O6]

I'm already in his voicemail queue.

 

[mrboatman]

/this\ The 12 o clock 6 o clock variety will barely fit the F engine adjuster bracket, and will not have an adequate range of motion for adjustment as the belt slackens.

Now that explains why I had to make a special bracket for the adjustment bracket. The original bracket I could not get the correct belt tension. I never understood why the bracket hit the alternator. So I just changed the bracket angle so it would clear. That was many years ago!!
JP

 

[C6H12O6]

I heard back from Mark, but only by voicemail. He's a tough guy to get ahold of, and so am I during the week. School teacher schedule doesn't work very well with his tough availability. Mark, if you're reading this, thanks for getting right back to me. Sorry I couldn't take your call.

He's got one (sounded like the standard 40A), but with no viable core and shipping, the price is pretty high. I'm sure it's better than what I have and it's probably a great rebuild, but damn, it's spendy. I'm still going to try to get him this week, but in case anybody here knows, do any of the 50/55A alternators have the single mount at the 1:00 position?

Sure tough to sort out online and nobody at the local parts stores are any help at all. Napa can order me the Bosch unit, which sounds like the better option for a high-volume rebuilder, but all the pictures I can find are at a funky angle and it looks to be another 12:00/6:00 alternator. This is all made even more confusing because of the nonsensical spec sheets all over the internet. The web seems to use 40A, 45A, 50A and 55A interchangeably—even within the specs for the same alternator. So confusing.

 

[65swb45]

It is definitely a 55amp. I had my rebuilder specifically check it before HE rebuilt it. One man shop, like me. I like supporting small shops. Haven’t had a single warranty issue with him in the 15 years or so I’ve been using him.

If you’re up late I can call you tomorrow after hours. I will be available at the shop off and on to 8pm. Hth

 

[C6H12O6]

I bit the bullet and ordered the 55A early-style alternator from Mark. Buy the good stuff and it only hurts once, right? He also had the right brake parts and knowledge to help me figure it out. That alone is worth the cost.

Thanks to everybody for your comments, and to Mark for taking the time to help me wade through all this.

 

[65swb45]

I’m not embarrassed to admit Steve taught me something too. I occasionally collect parts for a LONG time without needing to figure out all the nuances. The short temp sensors that came after my harem’s production run (64,65,68,69) just get thrown in a box. Steve told me the difference between the WATER temp sender and the EMISSIONS temp sender.

This is just some of the hoard. The pre-67 stuff and the NOS stuff also get stored elsewhere.