Hello gents,

I need all the help I could get with this problem. I'm trying to replace the master cylinder. I tried to get the nuts off where the hydraulic lines meet the cylinder but they're not budging. They're on really tight and look rusted.

I'm using a 10mm flare nut wrench to try to get it off. The first attempt rounded the nut a bit. It's still got a grip but obviously now that it's even the slightest bit rounded, any further attempts will be harder and round further. I've noticed that even though this is the proper wrench, if I put the wrench over the nut and jiggle the wrench left/right it has a bit of room. I thought there would be no room and the wrench would be tight on with most grip but this is not the case!

I'm tempted to use PB Blaster but I'm afraid the oil will work into the hydraulic lines. Are my fears unfounded? I'm really at an impasse here if I can't get these off.

Would vise grips have a better chance than the flare wrench? I also have to note that the wrench doesn't seem to go on 100%, almost like the rust is preventing it from doing so. I can't get in there so I can't even hammer it on. The wrench is also small, maybe six inches long so that might not be providing enough torque.

 

I've used vise grips on brake line nuts that were starting to round out, It worked well but you have to make sure that it is on there very well and super tight otherwise you will just take what remains of those nubs clean off.

 

There's another type of Vice Grips a Honda mechanic told me about years ago that he uses exclusively on brake lines, especially the real tight ones. It's the Vice Grip 4LW model. I picked up a set (different sizes) of that type of Vice Grips years ago too.

I would say to use a penetrating oil on the rusty brake line. If they have rust, what's a little penetrating oil. You probably will be flushing the brake fluid anyway.

 

Spray it with PB BLASTER let it sit hit it agin and let it sit give it one hr. then try the vice grips