'72 C30 Alternator

[CJ Mark]

Hi all.. I need to replace my alternator but I'm not sure what the correct amperage should be. It's a 1972 Camper 30, 2WD, 350 V8 Long bed.

How do I determine the correct replacement alternator?

Anyone know of a quality vendor that won't cost an arm and a leg? I just use the truck for the occasional load carry.

Thanks in advance!

Mark

[SS Tim]

Well first off "Custom Camper" did not change the alternator capacity. It would be the standard 61 amp output for your V-8 truck. Are you sure it is the alternator and not the regulator? Is it still the stock externally regulated setup? All too often cheap rebuilds are an expensive waste of time. Might even want to look into rebuilding (as in having it rebuilt) yours if it is not a DD.

[SS Tim]

How about a picture of your C/30 pickup? Sounds like it might be a Longhorn.

[mud.man.rj]

Like SS Tim said the regulator is separate from alt, and if miled out replace both as neither one is expensive, should be 61amp as noted.

[CJ Mark]

Thanks for your responses!

Quite obviously, I possess very limited mechanic skills.. and even less electrical knowledge. When the truck wouldn't start I had AAA come out to start it up but the guy put a tester on it and said the alternator needed to be replaced because it was over charging the battery. I drove the truck home and the battery, which is not old, was still dead.

Looking online I saw some replacement alternators that were 100 amp so thanks for clarifying that I should get the 61 amp alternator. But it sounds like I need to check the regulator as well. Is there a simple way of doing that or do I need to take it to a professional?

Thanks again! I'll post a couple picks of the truck later today.

Mark

[MikeyMan]

You will probably have to change the voltage regulator anyway. I'm not sure how to test it. If your truck has the original wiring, you'll find the external voltage regulator mounted on the driver's side radiator core support. A faulty regulator could cause your over-charging.

I had a regulator fail on me while driving on the highway. My Amp gauge pegged high for a while, then BANG, dead. The over-charging fried my battery & melted the fusable link, killing the power and causing a backfire of the engine.

Your battery may be damaged.

[CJ Mark]

Thanks Mikey! I'll check out the regulator, too. I appreciate your help!

Mark

[CJ Mark]

So.. checking out E-bay for an alternator. The closest match I see is 66 amp alternators.. I'm not finding any 61 amp models.

Can I use the 66 amp model without any problems?

Thanks!

Mark

[MikeyMan]

Your alternator may be fine, it could just be the EXTERNAL regulator.
Most of the newer vehicles have the INTERNAL regulator, thus you replace the alternator as a whole. Your AAA guy assumes it's the alternator causing the over-charging because most have the internal regulator.

You need to determine which style of alternator you currently have.
You can identify by the type of plug.

Check out this post, then click the link in the 2nd post:
http://67-72chevytrucks.com/vboard/s...d.php?t=431072
Read post #44 & #45 about identification:
http://67-72chevytrucks.com/vboard/s...=415738&page=2

More good info:
http://www.madelectrical.com/electri...elcoremy.shtml

You could take your alternator off the truck and have it tested. Many auto parts stores will offer free testing of Alternators, Starters, and Batteries. It would be a good idea to bring your battery in for testing too, it may have been damaged from over-charging.

[Kidd-7]

Check out this thread for some more info....

http://67-72chevytrucks.com/vboard/s...d.php?t=519033

[CJ Mark]

So.. it's never easy.

There are plugs on the side AND the back of the alternator. So I'm not sure if it's regulated internally or externally. In addition, I found the regulator attached to the front radiator wall and there are wires attached. The problem is I've got a second battery shelf right over it so it's tough to trace the wires.

I've got a couple photos of the alternator and the regulator. Now I'm trying to figure out how to post them here? I tried to find the albums section but no luck.

Thanks for your patience with a greenhorn! Any help is much appreciated!

Mark

[CJ Mark]

Sorry.. trying to upload photos. That didn't work!

[CJ Mark]

Okay.. here they are.

Mark

[MikeyMan]

Looks like you have an externally regulated alternator.
If you disconnect the plug, you sholud see the 2 prongs run parallel like railroad tracks ( l l )
The internal regulator will be end to end ( - - )

I would remove the alternator and take it to the parts store for testing. Have your battery checked too.
Replacing the regulator shouldn't be too bad. Sometimes the 3 bolts that hold it to the core support will strip or spin. You may need a small vise-grips on one side, and a socket on the other. There are special rubber "nuts" that are used to mount the regulator:

http://www.ebay.com/itm/63-64-65-66-...5890e1&vxp=mtr

Make sure the contacts in the 4 wire plug are nice and clean. Also check the ground wire connection.

[MARKDTN]

If you do have to replace it, I recommend a rebuilt by Delco. Advance and O'Rieleys can get them or a local Delco distributor if you have one.

[CJ Mark]

Awesome info guys! Thanks so much!!

I'm hoping to take care of this today if I have time. I'll update you as things progress.

Mark

[CJ Mark]

Well.. I discovered that my truck is actually a C20 3/4 ton.. NOT a C30. Doh! Just had to look at the VIN explanation. So that changes some of my research but not a great deal.

I found a nearby Delco dealer with a rebuilt alternator and regulator in stock so I think I'm just going to replace them both and be done with it. Total is only about $60! The only question is that the guy on the phone says its a 55 amp alternator.

Any thoughts?

Mark

[MikeyMan]

The alternator on my 72 C/10 is actually stamped 55 amp right on the case. My 350 engine and th350 trans are not original, probably from a mid-to-late 70's.

The main thing is how many accessories you're running. If you have working Air Conditioning, high power stereo amplifier, auxiliary lighting, etc., you might need more juice. A 55 amp should be fine.

Get your battery checked out too.

[CJ Mark]

Well.. installed the new alternator and regulator and drove around for 20 minutes. Came back home and turned it off. Turned the key back on.. and nada!

So I pulled the battery and took it to the Delco dealer where I got the alternator and regulator. The guy took one look and said.. yep.. that's an OLD battery!

I replaced it.. brought home the new one.. put it in and zippo.. the truck started right up! Now I'll take it to check that the charging system is doing what it's supposed to!

Photos coming soon!

Thanks everyone for all your help!

Mark

[SS Tim]

Originally Posted by CJ Mark

So.. . ...The problem is I've got a second battery shelf right over it so it's tough to trace the wires...

Mark, Sorry but I missed this the first time through and wanted to touch on it now. It sounds like you have the problem under control and that everything should now be good to go. However your statement, as quoted above, may be relevant to the overall problem. If what you have described is in fact the factory TP2 Auxiliary battery there might be wires laying about causing a current drain as well. Might try looking around and seeing what is under the hood. Actually first check your SPID on the glove box door and see if you can find the TP2 option listed. Also don't pull the bracket and chuck it, factory TP2 trays are sought for.
Just a reminder...
"How about a picture of your C/30 pickup? Sounds like it might be a Longhorn."

[CJ Mark]

Hey Tim..

Thanks for your note. I pulled out the tray for the 2nd battery temporarily but just to get access to the regulator. I did check for dangling wires and all seemed to be in order. As mentioned, I replaced the regulator and alternator and finally the battery.

Everything seems to be working okay for now but I'm going to get a buddy to help check the system later this week to be sure. I will replace the tray once I am sure everything is functioning properly.

Now that I can drive the truck again.. I'll get it cleaned up and shoot some new shots. However it is a Custom Camper C20.. not a C30 as I initially thought. I had to go back and look at my title and figure out the VIN info to be sure. And it has the chrome Custom/20 marker right on it! I should have just looked at that first!

It's seen better days but it's still a sweet old truck. Dad bought it when I was 18 in '72.. and I eventually inherited it a few years ago. I don't use it much since the 350 V8 just sucks down the gas but it is very useful when I need to haul something! I've got a canopy top on it which helps since I end up using the bed for storage at times.

Have a great day everyone!

Mark