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82 Rabbit with AC Alternator mount at the AC bracket

Posted: Sat Dec 05, 2015 11:24 am
by 82vdub
On ole 82 (82 Rabbit with AC), the alternator was wobbling very bad in it's lower mount (the AC mounting bracket). I got a replacement alternator and that comes with a flanged sleeve on the one side of the mounting tab. The mount position on the AC bracket has what looks like a sleeved bushing on it that may slip to provide a tight fit to the alternator mount. I can't get this sleeve to slip so I can get the replacement alternator in. Is this sleeve supposed to slip, or do I need to deal with what I'm stuck with?

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Re: 82 Rabbit with AC Alternator mount at the AC bracket

Posted: Sat Dec 05, 2015 6:35 pm
by bscutt
It is pressed in and the alternator normally doesn't have one in that spot, at least not on all the ones I have seen. You may be able to coax it to move in the bracket using a large C-clamp and a large socket or bushing. Possibly a torch to heat things up too.

Re: 82 Rabbit with AC Alternator mount at the AC bracket

Posted: Sat Dec 05, 2015 9:13 pm
by 82vdub
Before posting the original post, I went out to the two parts cars I have out back. They are non AC cars, so they are different, but the alternator mount was a similar shape and configuration as the mount with AC. Each of those two cars had this bushing, and each of them had the bushing in a different spot (in relation to the flange that it mounts in). Each of the alternators in those two cars also had a bushing with a flange on it on that right side of the alternator mount. This was likely to fix the issue of the aluminum wearing away over time. But, since the bushings were in different positions on these cars, this lead me to believe that the bushing should slip, similar to a brake caliper bushing. I did the C clamp, hammer, heat and everything else I could think of (except pulling the AC bracket off and putting it into a press - for a real experience of pressure). Nothing budged it. Years ago (that's many), I tried to do the same thing with the same results. Since I was running out of time, I ended up grinding down that bushing and installing the new alternator as snug as I could get it. This probably isn't ideal, since any alternator that I get that's rebuilt could have had more machining to the aluminum housing, making the mounting shorter. This would be fine if this bushing actually slipped, but in this case, it doesn't seem to.

I typically have my alternators rebuilt by a local rebuild shop, so for me, this should be fine for many years. However, in the event that I do wear out a housing in some manor (have worn out two now), I will be forced to get another alternator (or housing) and that's when I could have issues with the mount not being the right size to make it to fit snug.

Re: 82 Rabbit with AC Alternator mount at the AC bracket

Posted: Sat Dec 05, 2015 10:52 pm
by Fatmobile
I put a bolt through it, a socket on one side so the bushing can slide through/inside.
A washer up against the head to push the bushing back in toward the bracket. Snug the bolt and it shoves it back.

Looks like your alternator has a metal washer for the bushing to tighten against.
Some don't, so I put a washer on the end of the alternator pivot hole. Otherwise the bushing wears into the aluminum.

Re: 82 Rabbit with AC Alternator mount at the AC bracket

Posted: Sun Dec 06, 2015 12:18 am
by 82vdub
I didn't try the bolt trick to try to get the bushing to move back, but I did put a bolt through it to try to tighten down on itself in an attempt to get it to at least rotate. No luck. Even though it looks like it's a bushing that's supposed to move back, I wasn't 100% certain. I thought it could have been pressed in, so it's a one way deal, but getting it to rotate would have at least told me that it's separate from the cast housing. I was trying to learn anything about it that I could.

The original alternator and the one just removed had a recess on the right side of the mounting flange, which would mate with the bushing. The replacement alternator has a bushing with a thrust face on it installed. I removed it, and there was a 3/8" machined hole in the housing for the bushing to fit into. No installing that alternator with the bushing removed.

Re: 82 Rabbit with AC Alternator mount at the AC bracket

Posted: Mon Dec 07, 2015 8:21 pm
by bscutt
Interesting that you found more than one configuration but I guess I should not be surprised. I have never tried to press the bushing out on mine but the day may come. I'd like to take mine completely apart and see if I could get a machinist friend to bush the whole mess but his time is hard to come by so that may never happen. I think the design is pretty weak on the AC cars and as a result the vibration wears out the bushings, the alternator body, and so on. Mine works ok but the belt is always a little loose and floppy and the alternator will definitely move slightly when you rev up the engine. But for a variety of reasons I only drive the car in certain weather conditions and trade off with the other vehicles so in spite of the alternator flexing it will probably last a long time (not necessarily miles though).

Re: 82 Rabbit with AC Alternator mount at the AC bracket

Posted: Tue Dec 08, 2015 11:46 pm
by Fatmobile
bscutt wrote: see if I could get a machinist friend to bush the whole mess
Bush the whole alternator pivot hole?
I've seen that done. It made the aluminum so thin it broke.

Re: 82 Rabbit with AC Alternator mount at the AC bracket

Posted: Wed Dec 09, 2015 5:13 pm
by bscutt
well scratch that idea. Glad you shared that.

Re: 82 Rabbit with AC Alternator mount at the AC bracket

Posted: Wed Dec 09, 2015 7:56 pm
by 82vdub
I got two alternators for the job (one with a pully and one without) and used the one with the pully cuz I didn't want to spend 4 hours changing a pully, and end up damaging the new alternator). So the pullyless one is going back to the store. I just went to pull out the bushing that's machined into the end of the housing of the rebuilt alternator that I have to show how thin the wall ends up being, but no luck getting it out with my pocket knife.

I will say that with now 424,000 miles on Ole 82 and using a local rebuild shop for my starters and alternators, about 100,000 miles ago the original alternator housing was worn so bad where the end of the alternator rotor shaft went into, I needed another housing. Either that or machine the hole larger and bush it, but it's easier to get another housing. The rebuild shop had a housing on hand, so that's what was in the car until a bit ago. So, 325,000 miles for an alternator housing isn't really that bad, IMO, but this last one only lasted for around 100,000 miles. It probably wasn't in stellar shape to begin with.

Below are pics of the old alternator. You can see that the whole internal shaft area is ovaled out. This one would need the opening welded up and re-drilled to make it new again, or another bushing to go into both ends.

Once I get the engine out again and take the brackets off etc, I will look closer at the bushing that's supposed to come out. I'd like to bush that with something that actually works like it's supposed to, then there would be enough pressure on the alternator that it shouldn't wobble. As mentioned before, from what I found in the differences with the two parts cars out back, that should be a bushing that moves. If it did, this wouldn't be an issue.

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Re: 82 Rabbit with AC Alternator mount at the AC bracket

Posted: Sat Dec 12, 2015 12:25 am
by Fatmobile
A washer on one end so the bushing won't wear into the aluminum and a "spear" of stainless in the ovaled-out hole on the other end.

Re: 82 Rabbit with AC Alternator mount at the AC bracket

Posted: Sat Dec 12, 2015 11:08 am
by 82vdub
I did try machining a washer to fit in the concave end, but I couldn't get the alternator installed without the washer falling out. Would have been different if that bushing would have moved, but it ended up being too tight of a fit.

Re: 82 Rabbit with AC Alternator mount at the AC bracket

Posted: Sun Dec 13, 2015 10:24 pm
by Fatmobile
Did you try the bolt trick?

Re: 82 Rabbit with AC Alternator mount at the AC bracket

Posted: Tue Dec 15, 2015 11:44 pm
by 82vdub
I didn't try a bolt to move the bushing, but did a C clamp and socket. I also threaded a bolt into it and nut on the other side with the intention of trying to get the bushing to spin (to prove to me that it was in fact something that should move). That failed too.