I have a 1975 Cutlass Supreme with a rebuilt small block Chevy engine in it. I need to replace the battery cables.

I cannot for the life of me disconnect the negative cable from the engine. The nut (bolt?) will not budge. I used WD-40 and then tried after a few minutes.. nothing. Tried again after a few hours.. nothing. Any tips?

Also, I have followed the positive cable to its connection, but I cannot disconnect it as is. There is too much in the way. Any idea how to go about this? Some suggested jacking it up to reach it from below. Sound like a good idea?

Thanks!

 

I am by no means an expert at any of this, but I can tell you to get yourself some PB-Blaster or similar rust penetrating oil. It will work much, MUCH better than WD-40 for breaking loose rusted stuff.

I have used it to remove my very frozen, stuck exhaust manifold bolts simply by spraying PB-Blaster on each of them once or twice a day for a week. By the end of the week, they twisted out easily and completely intact.

Don't try to use Blaster for regular lubrication though (that's where WD-40's much better).

 

The negative cable, I'd continue to soak it with penatrating fluid like Kroil or PB Blaster. You could try heating it with a torch but it's going to burn/melt the cable insualtion making a mess. I'd pull the starter off the car to replace the positive cable. On an Oldsmobile engine I'd jack it up, make sure you have jack stands and once on them try to shake the car. If it wobbles reset the stands before crawling under it. Then pull the starter out the bottom. I suspect with your engine you'll want to do the same thing. I hope this helps! John