Page 1 of 1

Replacing Alternator - Advice

PostPosted: Thu Apr 25, 2013 12:18 pm
by Marcal
I'm replacing the alternator on my truck, since it died on me yesterday morning. It's pretty straightforward, but the bolts are really stuck in there. Can anyone recommend a good penetrating oil or something that will loosen them up a little?

Also, what is the best way to get the wiring clips out? The top one came off with no problem, but the bottom one seems a little tricky.

Re: Replacing Alternator - Advice

PostPosted: Thu Apr 25, 2013 1:21 pm
by danleym
PB Blaster usually seems to work well. You should be able to get it at any auto parts store.

I don't know what kind of truck you're talking about, but a lot of alternators have a wire that is held on by a small nut, and sometimes they're really hard to see, so make sure that's not the case. Other than that, you just gotta figure out where to squeeze or get a flat screwdriver to fit into. I've seen some really stupid connectors before. Just go slow, because it really sucks when they break.

Re: Replacing Alternator - Advice

PostPosted: Thu Apr 25, 2013 1:35 pm
by Marcal
1992 F-150, my big white rig.

On the alternator in my truck, there's a wiring clip on the top left toward the back, and one on the bottom left, in addition to the two bolts and the ground wire. They both have plastic connectors, but are slightly different from each other. The top one came off with a little persuasion from a screwdriver, but the bottom seems different somehow.

Re: Replacing Alternator - Advice

PostPosted: Thu Apr 25, 2013 3:10 pm
by Stu_Rock
The best accessible penetrating oil I've found is a homebrew mix of acetone and automatic transmission fluid. It's a well-known trick; just Google "acetone atf" to see lots of commentary. The two ingredients are somewhat immiscible, so you have shake before each squirt.

For a commercial product, Kroil is the one.

I can't comment on the electrical connector. Maybe it will be easier once the alternator is loosened/freed?

Re: Replacing Alternator - Advice

PostPosted: Thu Apr 25, 2013 3:28 pm
by Marcal
Interesting tip - thanks for that.

The bolts aren't rusty, really, but just stuck really tight. Steel bolts and the aluminum alternator casing must have reacted over time. Will this acetone mix work for that?

Re: Replacing Alternator - Advice

PostPosted: Sat Apr 27, 2013 3:07 pm
by Marcal
Decided to go with Liquid Wrench, which loosened everything right up after I let it soak for a while. Once I got the bolts loose, the alternator was out in 5 minutes. Let me just say that the wiring is a little tricky, and 20-year old plastic is brittle. I decided to put a new serpentine belt while I had the old one off anyway; that was probably the hardest part of the whole job.

All in all, a pretty easy repair.