Solvent for undercoating?

[Grandpa Shooter]

It has taken me two days (on and off) to get four 15/16 nuts loose for the U-bolts on the spring pack on our motor home.  I have used a 1/2 socket with 17" breaker bar and 2-3 foot pipe cheater to get them off.  Only at the very end of the threads could I use a ratchet.

I have sprayed them repeatedly with two different brands of "break free" product and it does not seem to penetrate the undercoating at all.  After I reassemble the side I am on, I still need to do the other side. I thought about heating them up with my plumbing torch, but I promised Lady Shooter I would not have any "accidents" while she is away

Any suggestions folks?  The motor home came from NY and does not have any rust underneath and no rusting rocker panels.  I am glad for that, but they could have kept it off the suspension and shock assemblies.

[280plus]

I hate to say it but I'm thinking heat is the answer. A fire extinguisher close by would be smart and I'd be dang sure I knew where the gas tank/fuel lines are in relation to my flame. Be careful!! 

[cassandra and sara's daddy]

i was thinking heat gun or even soldering iron

[Declaration Day]

Tal-Strip, available at any local auto parts store. 

[RocketMan]

I think C&SD is on to something with the heat gun idea.  Not so much to break things loose as to help remove the undercoating altogether.

[Jim147]

You might try lighter fluid or the bug and tar remover you can get at the autoparts stores.

If it doesn't work a follow up with heat will take care of everything.

jim

[TMM]

i've never encountered anything that gasoline and/or carb cleaner couldn't fix...

some wire brushes/wheels couldn't hurt, either.

TMM

[roo_ster]

Acetone & a wire brush.

[Grandpa Shooter]

I hate to say it but I'm thinking heat is the answer. A fire extinguisher close by would be smart and I'd be dang sure I knew where the gas tank/fuel lines are in relation to my flame. Be careful!! 

After I posted this I looked to see where the gas tank is ..Only about 10 inches from where I would be working.   NO THANK YOU!  That's too close for me.

Tal-Strip, available at any local auto parts store. 

How do you define "local"?  I am about 25 miles from the closest "local" parts store.

I thought about an air wrench, but they won't fit in where I am working, and an air ratchet doesn't develop enough torque to get it done either.  As sore as I am right now after finishing one side, I will be lucky if I can even walk tomorrow, let alone working on the &&&&&%%%$$## thing. 

I am doing it while the Lady is away so that she doesn't insist on taking her turn on the bar and end up hurting herself trying to keep me form hurting myself.  I truly do love that little Lady

[Jamisjockey]

Acetone, or carb cleaner?  Carb cleaner comes in a nice spray can, usually with a straw, too.

[never_retreat]

[Grandpa Shooter]

Where was the picture taken?  Looks like our property!

[alex_trebek]

I would reccommend Lye (or another chemical that has a high pH, aka calcium/sodium hydroxide) containing cleaners. I think easy off oven cleaner has lye in it.


Second solvent I would try is kerosene.

An alternative to a torch is an electric heat gun intended for paint removal. I think that would be safer than an open flame.

I think that the dangers of using flammable solvents, fire, and AZ climate should be obvious, I trust you will take the necessary precautions. Lye is very water soluble, it needs to be removed prior to heat application.

[Nick1911]

Just because no one has said it yet...


Detcord.
 

I don't really have anything useful to add.  I think some mechanical means are in order, though...  wire wheel, perhaps.

[charby]

Acetone & a wire brush.

angle grinder with wire brush wheel

[cassandra and sara's daddy]

new ubolts and nuts  dremel tool and cutoff wheel to remove old ones

[Tallpine]

new ubolts and nuts  dremel tool and cutoff wheel to remove old ones

Yeah, I was sorta thinking that too ... 

Are you changing out the springs, axle, or both ?

If both, you could have just pulled the bolts on the ends of the springs and pulled the whole works as one unit.

[Grandpa Shooter]

Well the good news is the operation is over.  The bad news is that one of the 1/2" u bolts got uppity with me so I snapped it and the bolt off.  That'll teach it to refuse to come off.

I guess those Wheaties and other healthy foods must be working.  I haven't been able to break anything on purpose in about 4 years.

The break cleaner as solvent works, as long as you don't take a break for coffee or anything else.   When the undercoating hardens back up it is worse than it was to start with.

The rear end now sits two inches higher and I will test drive it to see if the front end is a little tighter on the road.  It was a little too squirrely before.  Only have a few more things to do and it will be road ready!

[Triphammer]

Ed's Red. Combination solvent for everything I've tried.

[alex_trebek]

GS:
Congrats. Good job on making an example of the stubborn bolts. It wil keep the others in line.

[French G.]

I was gonna suggest a die to clean the exposed threads, but I suppose breaking the bolt works too.

[Grandpa Shooter]

I was gonna suggest a die to clean the exposed threads, but I suppose breaking the bolt works too.

Sometimes you just gotta give it that extra "tug"  As long as it doesn't involve my left hip or right knee, it is gonna let go one way or another!

[Tallpine]

So you replaced the springs