Re: Rebuilding My 1988 US-spec M5
Posted: Apr 15, 2020 3:08 PM
So I took a first swag at cleaning up the battery box. When I first took out the trunk liner parts and removed the battery, it was obvious that there was rust & corrosion in the box, likely from a leaky battery. My main concern was that whatever had leaked out of the battery and into the box had also dripped down under the box and created issues in an area that I don't know how to get to.
My plan was to "curtain" off the battery box and media blast the box in place. Things went mostly according to plan, though it became difficult to do more than a few seconds of blasting at a time before the media would start to fill up the box.
After some blasting, I think I'm OK with the existing box. I'll likely curtain just the box off again and give it another blast. That "after" pic isn't great, but if I get close up to that reddish residue looks more like film left over from the POR15 rust remover. The only damaged metal I'm seeing is that a portion of the forward battery hold-down is rusted away.
The better news is that I also managed to squeeze my bore scope into a few spots under the box (I'll edit this post with a pic if I can get the rig set up again), and I didn't see any rust at all under the box. It was dirty, but no corrosion that I could see. If anyone has any advice on how to get some primer or POR15 under there, please let me know, but my current thinking is that I'm not going to attempt to remove or replace the battery box.
EDIT: I got motivated and stuck the borescope in there again. After yesterday's cleaning, the scope actually slipped in more easily.
Those were the two dirtiest spots I could find. I'm pleasantly surprised a the lack of corrosion in there, and I think I'll leave the box in place. Just clean it up a bit more, POR15, paint.
My plan was to "curtain" off the battery box and media blast the box in place. Things went mostly according to plan, though it became difficult to do more than a few seconds of blasting at a time before the media would start to fill up the box.
After some blasting, I think I'm OK with the existing box. I'll likely curtain just the box off again and give it another blast. That "after" pic isn't great, but if I get close up to that reddish residue looks more like film left over from the POR15 rust remover. The only damaged metal I'm seeing is that a portion of the forward battery hold-down is rusted away.
The better news is that I also managed to squeeze my bore scope into a few spots under the box (I'll edit this post with a pic if I can get the rig set up again), and I didn't see any rust at all under the box. It was dirty, but no corrosion that I could see. If anyone has any advice on how to get some primer or POR15 under there, please let me know, but my current thinking is that I'm not going to attempt to remove or replace the battery box.
EDIT: I got motivated and stuck the borescope in there again. After yesterday's cleaning, the scope actually slipped in more easily.
Those were the two dirtiest spots I could find. I'm pleasantly surprised a the lack of corrosion in there, and I think I'll leave the box in place. Just clean it up a bit more, POR15, paint.