Replacing Alternator - Questions

Russell

Russell

Active member
Jan 2, 2017
357
88
28
Dunedin, Florida
With regard to replacing the alternator:

1) Can I replace the alternator from the top? Is there a link to a tech session write-up describing an efficient procedure for replacing the
alternator?

2) Should I install a new belt with it? Current belts are 2.5 years old, with about 6000 miles on them. Can I install a new alternator belt without
removing the other belts? Should I replace all the belts? I do not have a belt tension tester, it there a reasonable rule of thumb for proper belt
tension?

Related Question: I bought new spare belts 2 years ago. Do unused belts age out like tires? The spares are stored under the couch.

All helpful suggestions are appreciated. I'm always learning. Thanks.

--
Russell Keith,
1978 Eleganza II "Harry" 403, Danny Dunn Tranny (w/shift kit, 3.50 sprockets, Allison), Thorley, Stock Brakes w/Remote Vacuum Brake Booster, Dakota
Digital Dash, 6.5kW Onan, Dunedin, Florida
 
I don’t know of any tech session but it pretty straight forward. Check the maintenance manual. I think there are instructions there.

Take off the wire on the stud and unplug the other wires.

Take out the bolt from the lower front of the alternator and from the lower back. Remove the belt.

Then take out the pivot bolt from the top. It’s easiest to lower the alternator. You may have to turn the steering wheel to make room for it to go down.

Reverse this to install the new alternator.

You’ll have to remove the air conditioning compressor belt to remove the alternator and power steering belts. Your two year old belts should be fine. Keep the belts you removed for emergency spares

To tension the belts just push down on the center between the pulleys. It should depress less than a quarter inch.

Emery Stora
77 Kingsley
Frederick CO

>
> With regard to replacing the alternator:
>
> 1) Can I replace the alternator from the top? Is there a link to a tech session write-up describing an efficient procedure for replacing the
> alternator?
>
> 2) Should I install a new belt with it? Current belts are 2.5 years old, with about 6000 miles on them. Can I install a new alternator belt without
> removing the other belts? Should I replace all the belts? I do not have a belt tension tester, it there a reasonable rule of thumb for proper belt
> tension?
>
> Related Question: I bought new spare belts 2 years ago. Do unused belts age out like tires? The spares are stored under the couch.
>
> All helpful suggestions are appreciated. I'm always learning. Thanks.
>
>
> --
> Russell Keith,
> 1978 Eleganza II "Harry" 403, Danny Dunn Tranny (w/shift kit, 3.50 sprockets, Allison), Thorley, Stock Brakes w/Remote Vacuum Brake Booster, Dakota
> Digital Dash, 6.5kW Onan, Dunedin, Florida
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
Why ?
If it’s not broke don’t fix it !!!

On Sun, Dec 30, 2018 at 12:38 PM Emery Stora via Gmclist <

> I don’t know of any tech session but it pretty straight forward. Check the
> maintenance manual. I think there are instructions there.
>
> Take off the wire on the stud and unplug the other wires.
>
> Take out the bolt from the lower front of the alternator and from the
> lower back. Remove the belt.
>
> Then take out the pivot bolt from the top. It’s easiest to lower the
> alternator. You may have to turn the steering wheel to make room for it to
> go down.
>
> Reverse this to install the new alternator.
>
> You’ll have to remove the air conditioning compressor belt to remove the
> alternator and power steering belts. Your two year old belts should be
> fine. Keep the belts you removed for emergency spares
>
> To tension the belts just push down on the center between the pulleys. It
> should depress less than a quarter inch.
>
> Emery Stora
> 77 Kingsley
> Frederick CO
>

> >
> > With regard to replacing the alternator:
> >
> > 1) Can I replace the alternator from the top? Is there a link to a tech
> session write-up describing an efficient procedure for replacing the
> > alternator?
> >
> > 2) Should I install a new belt with it? Current belts are 2.5 years old,
> with about 6000 miles on them. Can I install a new alternator belt without
> > removing the other belts? Should I replace all the belts? I do not have
> a belt tension tester, it there a reasonable rule of thumb for proper belt
> > tension?
> >
> > Related Question: I bought new spare belts 2 years ago. Do unused belts
> age out like tires? The spares are stored under the couch.
> >
> > All helpful suggestions are appreciated. I'm always learning. Thanks.
> >
> >
> > --
> > Russell Keith,
> > 1978 Eleganza II "Harry" 403, Danny Dunn Tranny (w/shift kit, 3.50
> sprockets, Allison), Thorley, Stock Brakes w/Remote Vacuum Brake Booster,
> Dakota
> > Digital Dash, 6.5kW Onan, Dunedin, Florida
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://bdub.net/gmcmotorhome.info/
Alternator Protection Cable
http://bdub.net/gmcmotorhome.info/APC.html
 
You are right, Gene

6000 miles is not much on fan belts. They should probably last for 30,000 or more. However if he doesn’t put on many miles a year they would age out first.

Emery Stora

>
> Why ?
> If it’s not broke don’t fix it !!!
>
> On Sun, Dec 30, 2018 at 12:38 PM Emery Stora via Gmclist <

>
>> I don’t know of any tech session but it pretty straight forward. Check the
>> maintenance manual. I think there are instructions there.
>>
>> Take off the wire on the stud and unplug the other wires.
>>
>> Take out the bolt from the lower front of the alternator and from the
>> lower back. Remove the belt.
>>
>> Then take out the pivot bolt from the top. It’s easiest to lower the
>> alternator. You may have to turn the steering wheel to make room for it to
>> go down.
>>
>> Reverse this to install the new alternator.
>>
>> You’ll have to remove the air conditioning compressor belt to remove the
>> alternator and power steering belts. Your two year old belts should be
>> fine. Keep the belts you removed for emergency spares
>>
>> To tension the belts just push down on the center between the pulleys. It
>> should depress less than a quarter inch.
>>
>> Emery Stora
>> 77 Kingsley
>> Frederick CO
>>

>>>
>>> With regard to replacing the alternator:
>>>
>>> 1) Can I replace the alternator from the top? Is there a link to a tech
>> session write-up describing an efficient procedure for replacing the
>>> alternator?
>>>
>>> 2) Should I install a new belt with it? Current belts are 2.5 years old,
>> with about 6000 miles on them. Can I install a new alternator belt without
>>> removing the other belts? Should I replace all the belts? I do not have
>> a belt tension tester, it there a reasonable rule of thumb for proper belt
>>> tension?
>>>
>>> Related Question: I bought new spare belts 2 years ago. Do unused belts
>> age out like tires? The spares are stored under the couch.
>>>
>>> All helpful suggestions are appreciated. I'm always learning. Thanks.
>>>
>>>
>>> --
>>> Russell Keith,
>>> 1978 Eleganza II "Harry" 403, Danny Dunn Tranny (w/shift kit, 3.50
>> sprockets, Allison), Thorley, Stock Brakes w/Remote Vacuum Brake Booster,
>> Dakota
>>> Digital Dash, 6.5kW Onan, Dunedin, Florida
>>>
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> --
> Gene Fisher -- 74-23,77PB/ore/ca
> “Give a man a fish; you have fed him for today --- give him a URL and
> -------
> http://bdub.net/gmcmotorhome.info/
> Alternator Protection Cable
> http://bdub.net/gmcmotorhome.info/APC.html
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
Having changed six alternators in as many months this past season, and 1 the season before, here is what I learned

1977 Coach / 455

1. You can do most of the work from the top, but you’ll likely want to push the alternator up from the bottom (and have a helper to do it).

2. A known belt that is not showing signs of wear likely won’t be a problem.

3. All rebuilt alternators are not the same. I went through 4 rebuilds from Advance Auto Parts and one from another source. How they can take a core from the United States, ship it to China, do the rebuild, ship it back and do a quality job while making money at it is beyond me. Something had to suffer, and it was the quality. I finally found a new unit (assembled in the USA) that is working fine, making real DC. I’ll be making it my spare, and doing another replacement soon. AutoZone. Local folks in the trade tell me the NAPA rebuilds are quite good.

4. If your source for the alternator has testing equipment, test the new one before you put it on.

5. I put an oscilloscope on the coach to make certain the alternator is healthy and making DC without a bunch of noise. I lost a number of distributor modules with noisy output from failing alternator diode assemblies.

Dolph

DE AD0LF

Wheeling, West Virginia

1977 26’ ex-PalmBeach
Howell EFI & EBL, Reaction Arms, Sullybilt Bags, Manny Transmission

“The Aluminum and Fiberglass Mistress"

>
> With regard to replacing the alternator:
>
> 1) Can I replace the alternator from the top? Is there a link to a tech session write-up describing an efficient procedure for replacing the
> alternator?
>
> 2) Should I install a new belt with it? Current belts are 2.5 years old, with about 6000 miles on them. Can I install a new alternator belt without
> removing the other belts? Should I replace all the belts? I do not have a belt tension tester, it there a reasonable rule of thumb for proper belt
> tension?
>
> Related Question: I bought new spare belts 2 years ago. Do unused belts age out like tires? The spares are stored under the couch.
>
> All helpful suggestions are appreciated. I'm always learning. Thanks.
>
>
> --
> Russell Keith,
> 1978 Eleganza II "Harry" 403, Danny Dunn Tranny (w/shift kit, 3.50 sprockets, Allison), Thorley, Stock Brakes w/Remote Vacuum Brake Booster, Dakota
> Digital Dash, 6.5kW Onan, Dunedin, Florida
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
Step 1 in working on your alternator.
Disconnect the negative battery cable.

Sully
Bellevue wa

On Sun, Dec 30, 2018 at 3:02 PM Dolph Santorine
wrote:

> Having changed six alternators in as many months this past season, and 1
> the season before, here is what I learned
>
> 1977 Coach / 455
>
> 1. You can do most of the work from the top, but you’ll likely want to
> push the alternator up from the bottom (and have a helper to do it).
>
> 2. A known belt that is not showing signs of wear likely won’t be a
> problem.
>
> 3. All rebuilt alternators are not the same. I went through 4 rebuilds
> from Advance Auto Parts and one from another source. How they can take a
> core from the United States, ship it to China, do the rebuild, ship it back
> and do a quality job while making money at it is beyond me. Something had
> to suffer, and it was the quality. I finally found a new unit (assembled in
> the USA) that is working fine, making real DC. I’ll be making it my spare,
> and doing another replacement soon. AutoZone. Local folks in the trade tell
> me the NAPA rebuilds are quite good.
>
> 4. If your source for the alternator has testing equipment, test the new
> one before you put it on.
>
> 5. I put an oscilloscope on the coach to make certain the alternator is
> healthy and making DC without a bunch of noise. I lost a number of
> distributor modules with noisy output from failing alternator diode
> assemblies.
>
>
> Dolph
>
> DE AD0LF
>
> Wheeling, West Virginia
>
> 1977 26’ ex-PalmBeach
> Howell EFI & EBL, Reaction Arms, Sullybilt Bags, Manny Transmission
>
> “The Aluminum and Fiberglass Mistress"
>

> >
> > With regard to replacing the alternator:
> >
> > 1) Can I replace the alternator from the top? Is there a link to a tech
> session write-up describing an efficient procedure for replacing the
> > alternator?
> >
> > 2) Should I install a new belt with it? Current belts are 2.5 years old,
> with about 6000 miles on them. Can I install a new alternator belt without
> > removing the other belts? Should I replace all the belts? I do not have
> a belt tension tester, it there a reasonable rule of thumb for proper belt
> > tension?
> >
> > Related Question: I bought new spare belts 2 years ago. Do unused belts
> age out like tires? The spares are stored under the couch.
> >
> > All helpful suggestions are appreciated. I'm always learning. Thanks.
> >
> >
> > --
> > Russell Keith,
> > 1978 Eleganza II "Harry" 403, Danny Dunn Tranny (w/shift kit, 3.50
> sprockets, Allison), Thorley, Stock Brakes w/Remote Vacuum Brake Booster,
> Dakota
> > Digital Dash, 6.5kW Onan, Dunedin, Florida
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
No job is complete without vaporizing at least one wrench!

Dolph

DE AD0LF

Wheeling, West Virginia

1977 26’ ex-PalmBeach
Howell EFI & EBL, Reaction Arms, Sullybilt Bags, Manny Transmission

“The Aluminum and Fiberglass Mistress"

>
> Step 1 in working on your alternator.
> Disconnect the negative battery cable.
>
> Sully
> Bellevue wa
>
> On Sun, Dec 30, 2018 at 3:02 PM Dolph Santorine

>
>> Having changed six alternators in as many months this past season, and 1
>> the season before, here is what I learned
>>
>> 1977 Coach / 455
>>
>> 1. You can do most of the work from the top, but you’ll likely want to
>> push the alternator up from the bottom (and have a helper to do it).
>>
>> 2. A known belt that is not showing signs of wear likely won’t be a
>> problem.
>>
>> 3. All rebuilt alternators are not the same. I went through 4 rebuilds
>> from Advance Auto Parts and one from another source. How they can take a
>> core from the United States, ship it to China, do the rebuild, ship it back
>> and do a quality job while making money at it is beyond me. Something had
>> to suffer, and it was the quality. I finally found a new unit (assembled in
>> the USA) that is working fine, making real DC. I’ll be making it my spare,
>> and doing another replacement soon. AutoZone. Local folks in the trade tell
>> me the NAPA rebuilds are quite good.
>>
>> 4. If your source for the alternator has testing equipment, test the new
>> one before you put it on.
>>
>> 5. I put an oscilloscope on the coach to make certain the alternator is
>> healthy and making DC without a bunch of noise. I lost a number of
>> distributor modules with noisy output from failing alternator diode
>> assemblies.
>>
>>
>> Dolph
>>
>> DE AD0LF
>>
>> Wheeling, West Virginia
>>
>> 1977 26’ ex-PalmBeach
>> Howell EFI & EBL, Reaction Arms, Sullybilt Bags, Manny Transmission
>>
>> “The Aluminum and Fiberglass Mistress"
>>

>>>
>>> With regard to replacing the alternator:
>>>
>>> 1) Can I replace the alternator from the top? Is there a link to a tech
>> session write-up describing an efficient procedure for replacing the
>>> alternator?
>>>
>>> 2) Should I install a new belt with it? Current belts are 2.5 years old,
>> with about 6000 miles on them. Can I install a new alternator belt without
>>> removing the other belts? Should I replace all the belts? I do not have
>> a belt tension tester, it there a reasonable rule of thumb for proper belt
>>> tension?
>>>
>>> Related Question: I bought new spare belts 2 years ago. Do unused belts
>> age out like tires? The spares are stored under the couch.
>>>
>>> All helpful suggestions are appreciated. I'm always learning. Thanks.
>>>
>>>
>>> --
>>> Russell Keith,
>>> 1978 Eleganza II "Harry" 403, Danny Dunn Tranny (w/shift kit, 3.50
>> sprockets, Allison), Thorley, Stock Brakes w/Remote Vacuum Brake Booster,
>> Dakota
>>> Digital Dash, 6.5kW Onan, Dunedin, Florida
>>>
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
You'll have to alternate (pun intended) between top and bottom to get it changed out.

--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles,
Solar battery charging. GMCSJ and GMCMI member
 
If the belts are not worn, do not replace them. All of my vehicles except the motorhome have belts that are over 10 years old. I replace my
motorhome belts a few years ago because the were around 15 years old at the time and I wanted to try 1/2" wide belts. All of my spares are at least 8
or 10 years old.

Why are you replacing the alternator. It is really bad?

Almost all rebuilt brands (NAPA, AZ, Advanced) are done by a Cardone owned facility in Mexico. I have never had a problem with them, while others
like Dolf and Dan Gregg hated them. If I had one go bad on the GMC I probably would return it under their lifetime warranty. If it was on any other
of my another vehicles, I would probably take it to a local rebuilder. All of my other vehicles are over 150,000 miles and have never needed a
replacement since new, so no warranty om them.

Out the top is the way I usually do it. You also can do it all from the top except one bolt and then crawl under to remove the last one. This is not
a difficult job.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
If you decide on a higher amp alternator, and have a house battery failure (shorted cell(s)), beware.
The higher current can take out the isolater blocking diodes. Now if you happen to have the dash
blower on high the blower will go into WARP drive. For a very short time, then copious quatities of
blue (aka magic smoke) will come from the dash vents.

Said failure will only occur in bumper to bumper dead slow traffic 4 lanes wide. The driver will instruct
family to station by the door if it looks like a life endangering fire. Adjoining motorists will have no
sympathy to allow room to the shoulder. No we did not have to abandon ship,and a jumper wire across the
isolater allowed us to continue our journey. Wife still refers to the GMC as THAT THING.

Sigh
--
1977 Eleganza II
Ogden NY
 
Wow, good to know as lot of the coaches we work on here come with dead ones
and some do have extra hi alt.
Always learning.

On Sun, Dec 30, 2018 at 8:02 PM Ernest Dankert
wrote:

> If you decide on a higher amp alternator, and have a house battery failure
> (shorted cell(s)), beware.
> The higher current can take out the isolater blocking diodes. Now if you
> happen to have the dash
> blower on high the blower will go into WARP drive. For a very short time,
> then copious quatities of
> blue (aka magic smoke) will come from the dash vents.
>
> Said failure will only occur in bumper to bumper dead slow traffic 4 lanes
> wide. The driver will instruct
> family to station by the door if it looks like a life endangering fire.
> Adjoining motorists will have no
> sympathy to allow room to the shoulder. No we did not have to abandon
> ship,and a jumper wire across the
> isolater allowed us to continue our journey. Wife still refers to the GMC
> as THAT THING.
>
> Sigh
> --
> 1977 Eleganza II
> Ogden NY
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
> ...Said failure will only occur in bumper to bumper dead slow traffic 4 lanes wide. The driver will instruct
> family to station by the door if it looks like a life endangering fire. Adjoining motorists will have no
> sympathy to allow room to the shoulder. No we did not have to abandon ship,and a jumper wire across the
> isolater allowed us to continue our journey. Wife still refers to the GMC as THAT THING.
>
> Sigh

Thank you that was hilarious! Sorry but Its nice to occasionally receive affirmation that it's not just my luck.
 
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