I have found a few mentions of this on the web but wanted to try my luck with this group. I am replacing the flexible brake hoses and calipers on the front. One front side went off without a hitch. I also did the rear flexible hoses no issue. On the front side, I have loosened the fitting that connects the hard brake line to the flexible hose. It spins freely. This is a rust free car although it did require a little coaxing. Anyway, it will not disconnect like it is still stuck together despite turning independently freely. Based on what I’ve read this can be the symptom of it having previously been over tightened / over torqued down and “mushroomed” out at the bottom where the fitting is “flared” I guess

Please send any particular advice, experiences or tips/tricks my way if you have them…bummed that what was supposed to be an inexpensive repair may turn into replacing a brake line etc…

for the avoidance of doubt the attached is a picture of what I think was over tightened and will not separate from the hose (note obviously this is not a picture of the particular one in question that won’t separate, but sending just so it’s clear the part I’m speaking of that I think was overtightened)

thanks!!

 

If I'm understanding correctly the collar that is normally in the flexible line is now stuck to the fitting in your picture do I have that right?

 

Yes I think that’s right. The little 10mm flare nut that sometimes is hard to break loose (esp if car is rusty) turns fine and all the threads became exposed after breaking it loose and then unthreading it. Nothing was unusual up until the point where it’s at now where it should just fall away loose from the “collar” that is at the end of the flexible brake hose leaving me with the open end of the hard brake line to plug while I work on swapping out the caliper and hose. But despite exerting a lot of pulling on it, it won’t separate. I can keep turning the little flare nut freely but it just kind of turns in place with no more threads exposed because all the threads are out. So it is like something is caught at the very end preventing me from getting them apart. I don’t think it’s my error because all other three corners of the car I did with no issue already. The only explanation I’ve found online is it is a result of this little 10mm nut previously being overtightened to cause a deformation.

 

Why can't you just grab the "collar" with vice grips and twist it off. The flared end is inside the threaded portion the rest is what was supposed to stay in the hose.

 

Yeah I know what stays with what like I said already did 3/4 corners on this car with zero issues or leaks so I do know how they are supposed to come apart and thought this would be a 30 min job. I am using vice grips and applying what feels like decent force but won’t come off. Which makes me think metal is deformed in some way. See below from a thread on another site for what I think is my same issue in context of a different car. Just wondering if anyone has gone through this on this particular car and has any additional tips. Feels like this is a rarer issue because most mechanics understand not to apply all the force in the world on the little 10mm when re tightening but but the original owner of my car had a shop that did some suspect stuff as I am seeing. At this point I may just have a shop deal with it. I can do some stuff DIY but I don’t want to risk safety with damage to the break line.

 

Circling back on this thread in case searched. Toyota dealer confirmed the flexible hose was previously over tightened by prior owner’s mechanic which was my suspicion. It caused a deformation / mushrooming out of the hard brake line. They are going to trim a very small amount of hard brake line and re-flare it. It is a lesson to not over tighten the flexible brake hoses or you can damage the hard line.

 

wow sorry to hear your troubles but glad you've shared something that i am now aware of after working with flare nuts all these years!
never knew you could overtighten them to a point of flattening the flare and causing the inability to separate. learned something new.

 

Yeah. I guess it’s once again a lesson (not new to you all but new to me in the last year or so as I’m learning how to work on this car) that if you have a tiny little 10mm bolt like that, unless you really know specifically that you need to, you probably don’t need to go Rambo on it. If Lexus wanted you to, they probably would have made it a larger fitting…I think the prior owner’s shop just figured since it’s the brakes let me err on the side of tightening the hell out of it but they caused damage in the process. Thankfully they only damaged one corner out of the four.