Alternator Swap DIY

[DrTrae]

So my alternator went out last week and I got stranded at work! Got my buddy to ship me a new one, and proceeded to document the process. Alternator swaps are pretty self explanatory, but I couldn't find a single 1.8t DIY on here or the Vortex, so I thought I'd make one.

I also decided to upgrade to a 120amp alternator. In my personal opinion, it so far really has helped with the common power issues the 1.8t is notorious for. My headlights still dim a little bit when I roll my windows up or down, but not nearly as much as they used to. My bouncing idle has also completely disappeared. Anyway, on to the DIY!

Tools needed:
Pliers
Flathead screwdriver
Number 5 Allen wrench
16mm wrench (for belt tensioner)
13mm socket and wrench
8mm socket or wrench
Maybe an extra hand...

Note: If you follow my DIY exactly, you will need to replace the throttle body gasket, and need to get a throttle body alignment done with VagCom. If you don't want to deal with that, see FastAndFurious' post below, or just read the very end of this article.

Here's my Beetle rolling off of the tow truck into my driveway.


Here are the 2 alternators side by side for comparison.



First step, pull the intake pipe off of the throttle body after you loosen the clamp.


Then take this hose off the top of the throttle body.


Remove the 4 allen bolts holding the throttle body on. Neglect the fact that steps 1 and 2 have not been followed in this picture.


Disconnect this... connector.



Take tension off of the accessory belt and pull the belt off of the alternator. The wrench I used was an 18, but... a 16 would have been better. I didn't have one handy though.


Disconnect this plug on the alternator.


Take this black cover off of the nut. Remove the nut and then remove the ground wire. There is also a small nut that holds the wire harness to the alternator, remove that as well.


Unbolt the alternator. This is where the extra hand would have been nice. The belt tensioner just so happens to be right in front of the lower bolt. So you have to hold the tensioner in the untensioned position to get to it. Keep the extra hand around for when you get to bolting your new alternator in.


Then do all that in reverse. Like I said, pretty self explanatory. Here's my new 120A alternator bolted in.


Ground wire and connector back on.


And this shows the damage I inflicted on the fender and the throttle body port while trying to get the new alternator in.


Getting the stock alternator out was a squeeze itself, and the new one was juuuuuuust a little bit bigger. I'm embarrassed to publicly discuss how I got the new, bigger alternator in, so I'll refrain from doing so. I would definitely recommend removing the intake manifold before doing this. I just really did not have the time or patience to go to that extent. Hope this helps anyone that may want to upgrade to a bigger alternator, or just needs to replace their non-functioning one, but needed the extra confidence a DIY provides. Cheers!

Alternate method!
Apparently there was a much easier way to do this whole job! If you do it this way, you can go ahead and skip most of the first 4 steps. Obviously, the throttle body will probably inhibit your vision of the alternator slightly, but it shouldn't be much different.

If you take the passenger side headlight out, the alternator will fit straight through the hole. You won't have to take the throttle body off at all.

Credit for this info goes to FastAndFurious.

[FastAndFurious]

You dont have to remove the intake manifold to do a alternator swap, thats just ridicilous. Thats probably the worst advice you can give. You can get the alternator out the headlight, much easier and more room just remove the headlight and headlight cup and you dont have to touch the throttle body, just move the hose a little.

You should also note that if you are removing the throttle body, you need to change the gasket (5$) and do a throttle body alignment which is done via vcds and not everyone has one.

[DrTrae]

Oh wow. Yeah, I didn't even think to take the headlight out. Work smart, not hard. Right?

Thanks for the input!

[FastAndFurious]

Originally Posted by DrTrae

Oh wow. Yeah, I didn't even think to take the headlight out. Work smart, not hard. Right?

Thanks for the input!

hey no problem, just helping out the community.

Work smart , Yes and if your gonna work hard make it look good

[mlt]

According to Bentley, one is supposed to drive those threaded sleeves inserted into alternator (in a mounting ear at the very bottom right of previous picture) out on 4 mm to make installation easier. Mine was replaced 4-5 years ago and those sleeves are a bit rusted and were pretty much stuck now. Is there any trick as how to actually move them without hitting with a hammer? Are they perfectly cylindrical or do they expand towards one edge so it can be inserted in specific direction? Somehow I've managed to put it back without doing it, but it was a pain!

[rusman]

Wow, just found this post. I really wish I would have known to pull the alt through the headlight hole before pulling the TB!!!

What is the deal with resetting/aligning the TB when removing it? What happens if you do not do this?

[IndyTom]

Originally Posted by rusman

Wow, just found this post. I really wish I would have known to pull the alt through the headlight hole before pulling the TB!!!

What is the deal with resetting/aligning the TB when removing it? What happens if you do not do this?

Probably nothing but then again it could cause some issues and throw a cell. If it doesn't you should be fine. If it does a Throttlebody adaption should be performed. This usually can only be done via a VAG com/VCDS software.

But I wouldn't worry just yet. Put everything back together and see what happens. No need to worry about nothing.

[rusman]

Thanks IndyTom.

I was able to get the alternator out of the car with this beautiful tip of pulling it through the headlight hole. I really need to think out of the box sometimes .

[Spencer]

nice, man!

I wonder what kind of alternator upgrade I could get going? I think it'd be cool to augment it with a small solar panel, too.

[jdexter73]

Fast n Furious, that Alt is sick ! Please do a "How to" for how you found the patience to polish that thing.

[FastAndFurious]

you have to take apart your whole alternator and polish the shell then re-assemble.


If youd like one I can do it for you for a fee of course and ship it back to you

[rusman]

Not to steal any business from you, FandF, but there are businesses that do polishing.

[FastAndFurious]

usually businesses that do polishing dont take apart alternators

i guees you can expect a comment like that from someone that has never taken one apart or know whats involved