I swapped O'Reilly's BrakeBest wheel cylinders with AC Delco wheel cylinders and put them in my '79 Catalina. The threading fitment on the wheel side of the line is much better than with O'Reilly's parts. After doing that, I confirmed that my driver's side steel line is leaking on the axle, not from the back of the drum. I attempted to pull the line off at the equalizer with a line wrench, but that is just rounding off the flare nut. How should I go about breaking the thing free?
I sparingly tried some heat with my propane torch, but that didn't work. The gas tank isn't far behind me, and I'd like to keep myself and the car free of flames, so I didn't try it for long, haha. I've thought about grabbing it with vice grips and trying to twist it out that way, since the line is trash anyways, or cutting the line and slipping a socket over it to get at it it that way. Would either of these options be better than the other, or is there anything else you might recommend? This line job should be easy to replace compared to the rear main line I had replaced on my '99 Ranger, so I'd rather do it myself than pay the shop $150 to replace it.
You're talking about parts that have been together for over 40 years and they don't want to be separated. If soaking the threads in penetrating oil for a while and using Vise-Grips on the nut doesn't break the line free I'd just replace the entire part that it's attached to, plus the lines, and be done with it. (I believe you're talking about the junction block near the center of the rear axle, there's nothing special about it, it's just a simple fitting.) If making your own hard lines I recommend NiCopp line, it bends and flares really easily.
That is what I'm talking about, that splitter-type thing that the center rubber line comes down into. That came out fine when I replaced it. The nuts came out of the wheel cylinders surprisingly easy as well. I would have expected those to be more stubborn than the center nuts, they got plastered with everything the car drove through for 40 years. The center one's a little more protected by the differential, and just being directly under the car body. I'll give the PB Blaster and vice grips a shot.
Twisting with the vise grips got the rust to let go. I replaced the line, it's not pretty, but the leak stopped.
Pressing the brakes during the bleeding process, I noticed the reservoir fluid bubbles like a McDonald's cup does when you blow air into it. Fluid seeps from the back of the master cylinder, so that will need replaced.
Vise-grips are the ticket in the situation! Yeah, definitely need to replace that master cylinder. Even if it otherwise works the fluid seeping out the back will ruin the power brake booster not to mention the spectre of master cylinder failure leaving you without brakes!
I just had similar issue on my 1990 cadillac , I used 1mm flare wrench to try to loosen the line to the rear wheel cylinder, it did not work , I applied heat and peentrant and let it sit , I t did not work. Finally got it free by putting the flare wrench on the nut and clamping the end of the flare wrench hard with a pair of vice grips so that the head wrench on th enut could not flex. I tapped the flare wrench with a hammer and it broke free with no flare nut damage. It would have surely rounded the nut if I did not do that.