I've always been a believer in Kroil. I have some left of a gallon can with a date I wrote on it of 1985.. still works. Of course in that time I've gone through a number of "deals" that they offer on two-for-one or the like on aerosol cans.

This time I was not able to loosen the brake tube-to-hose connection on the right front of my 89 Crown Vic. Left side of the car, no problem at all.

I replaced hub/rotor, calipers/pads, and the brake hose. About 162,000 vehicle miles. It is a spare vehicle for a few weeks while my wife recovers from knee surgery, so I put it up on stands in the garage and sprayed everything with Kroil. That was a week ago Friday. That Saturday I tried to break loose everything and it all came except the one tubing nut.

I did the work for the left side and kept applying Kroil for several days. Everything I had to loosen it with just wanted to round it.

Yesterday I gave up and replaced the parts on the right side leaving the old hose in place.

One lesson I learned was that the other side came loose easily but I think it was the wrong size wrench. During my trials I decided it should have been an 11mm wrench, which I do not have in the flare nut pattern. I have all around it -- 10mm / 12mm, and 3/8 / 7/16. If I were starting over before rounding it began, I would get an 11mm. At the time I decided that, I wasn't sure it would have made the difference. An 11mm open end fit well, but would not loosen it.

Oh well.

I have used several cans of Penetro 90 in there also, and would have tried that if I had had some.

I DO have PB Blaster, but I had my money on the Kroil.

PB Blaster is unreal. I've never had that fail to break loose a rusted part.

I would not worry about it especially when you are talking brake lines. As for PB Blaster I have not found it to be better then anything else I have tried. Some parts need a penetrating oil, some heat and a hammer before they loosen up. I used half a can of PB blaster on the brake lines of my F150 and still needed plenty of help to get some of them lose. I ended up replacing both front calipers (bleeders were siezed) and hoses which was still a huge pain just getting the lines to seperate. I used quite a bit on the rear bleeders as well and still need to several taps from a wrench and more penetrant more tapping and so on before I finally got them to break loose and not just snap off.

I don't think it would have mattered what product you used in this case only the names would have changed.

I have an O2 sensor that would beg to differ. Still good stuff