850 Rear Hose Replacement?

[PeteB]

They are quite bad, I'll try to take a pic - threads on what to do about it?
It is interesting that the rust depends strongly on the type of material used, the
exhaust system must be made from good materials (stainless?) because the rest
of it is in fine shape. Even the clamp is perfect, just the studs and nuts were
grossly rusted. My neighbor saw this on a Nissan, the entire exhaust system was
nearly perfect, it is only 10 years old, but a similar clamp must have been made
from substandard material as the bolts and even the clamp were 25-50% rusted away.

[erikv11]

This thread from a couple years ago has lots of good info: viewtopic.php?f=1&t=49802

[PeteB]

Made some progress today, all of the joints that I tried to open so far were not frozen
except for the most difficult one so far. The one in front of the dirver's side rear
wheel has to be done by feel, and so far it won't budge. Hitting it with PB blaster,
WD40 and Kroil but I have to get the wrench in there by feel and can't get enough
leverage. I probably could use a better wrench, it is a Lowe's Kobalt and I'm
worried about damaging the nut.

[PeteB]

I'm bidding on a Snap on 11mm flare wrench on ebay.
I find that most of the cheap ones flex and I don't want to risk rounding
the nuts. I put vice grips on the cheap Kobalt when I did the fronts but
there is no room on the rears.
I have an old flare wrench from the 1970s that says forged on it but it is 10/12 mm,
the good old days.

Flare wrench thread: https://www.garagejournal.com/forum/sho ... p?t=141828

[skloon]

When removing hoses I cut the rubber off then use a six point deep socket to unscrew the fitting-I also have a set of crowsfoot flare wrenches from somewhere that help-

[cn90]

Or search forum for the dremel trick, basically cutting slowly on the hose's female side until it is almost done.
Make sure you don't damage threads parts on the pipe side.
Once the hose is removed, you will see this:

[PeteB]

Thanks, yes I remember that tip from a while back.
Reminds me to try some heat on it also.

[PeteB]

When removing hoses I cut the rubber off then use a six point deep socket to unscrew the fitting-I also have a set of crowsfoot flare wrenches from somewhere that help-

The hose end is held by the bracket, but I have to admit that the socket on it
seems to help, maybe by holding it more solidly to provide more force to crack it.

I think that if I could compress that spring behind the flare nut then the hose end
would turn. Seem to remember doing this on the fronts.

[abscate]

Or search forum for the dremel trick, basically cutting slowly on the hose's female side until it is almost done.
Make sure you don't damage threads parts on the pipe side.
Once the hose is removed, you will see this:

You probably won't see the drops....

[PeteB]

It is off.
I hit the difficult hose connection in front of the driver's side rear wheel with
PB Blaster, WD40 and Kroil, 3 or 4 times. Today I heated it for about 3 minutes
with a propane torch, aim the flame at the muffler so as to not heat up other things.
I held the flare nut with the snap on 11mm wrench and wedged it up against the
frame. I had pulled on the metal part of the hose end to release it from the notched
bracket and broke it free with a 6 point deep socket on the metal part of the hose.
It was tight the whole way probably due to corrosion in the threads.
I believe that the flare nut is a brass alloy so it looks okay.

Once it is all free the end of the hard pipe and flare nut can be pulled down about 2 to
3 inches lower so that it can be seen below the car.

The flare nut does not seem to want to turn free of the hard pipe, any tips on how
to free it up? Soaked it with PB Blaster and WD40, will give it some time.
I'll probably turn the hose if I can't free it up, then have to remove and turn the Y
connector that goes on the other end - a pain but perhaps easier than dealing with
damage to the hard pipe if I break it forcing the flare nut.
Strange that the hard pipe does not look rusty at all but is stuck to the nut.