Stuck bolts

[scott209]

Awhile back, someone posted the name of a good spray penetrating lubricant.

Does anyone remember?

Thanks, 

Scott

[Ronnie]

Everyone has their idea of what is best. I think the best I've used is AreoKroil but it is expensive and a little hard to find.  A lot of people like PB Blaster. I believe it is a lot cheaper and it can be found at Lowes.

[D-a-n-i-e-l]

Pb

[Barney Eaton]

There is a Utube test and that guy found Liquid Wrench did the best job,  with acetone/automatic transmission fluid mixture second.

Heat also works pretty good

[Kevin M]

Pb blaster is pretty much all I use on the ships I’ve worked on. I’ve seen it works better if you let it soak for a while. 

[Vincent Vega]

1 Liquid Wrench
2 PB Blaster

3 Kroil

4 Hot Wrench

5 Swearing

6 Easy out

7 Left handed drill bits

8 Helicoil

9 Sell it

In that order.

[Barney Eaton]

Vincent......where have you been?     I like your list.

I just run across another list that someone sent me, the source is Machinist's Workshop magazine (april--june 2007)   It list the product and the amount of torque needed to break them loose.

On other details .......like how long they let the product set on the screws/bolts

None/nothing...........516 #

WD-40.......................238#

PB Blaster.................214#

Liquid Wrench.........127#

Kano Kroil................106#

ATF-Acetone mix......53#    

 

I suggest you try different ones and see what works for you.  I have used all of them on frozen headlight motor screws and in some cases plus heat and have yet to find something that will free them.

[Ronnie]

1 hour ago, Barney Eaton said:

I have used all of them on frozen headlight motor screws and in some cases plus heat and have yet to find something that will free them.

 

Barney, you're the man when it comes to the headlight motors and you know a lot more about them than I do. From a machinist point of view, when you are removing the headlight motor screws you are dealing with an interference fit as well as torque when removing them. When those screws were originally installed I believe they  were forced into a hole without threads smaller than the diameter of the screw - much like a wood screw which has zero clearance between the threads.

 

As you know, machine screws and bolts have clearance between their threads and the threads in the hole they screw into. For any penetrating oil to work there has to be clearance between the parts for a wicking action to take place to get the lubrication into the threads. With the screws you are referring to there was never any clearance between the threads making it almost impossible for a wicking action to take place.  That might explain why none of the penetrating oils work well on the headlight motor screws.

[Barney Eaton]

Ronnie.........I do not consider myself a machinist, tool maker, or any of those specialized fields.... I spent 38 years in manufacturing,  first as a fixture, tool designer, then in processes, machine design, and a lot of other manufacturing areas....even a little time in quality.  The problem with the Reatta headlight screws... as you pointed out.........they used case hardened thread forming screws.....(for anyone not familiar with these,  there is a pilot hole in the soft aluminum casting, with an air power driver the thread forming screw, cuts into the metal and forms its own threads, saving time and money in manufacturing the assembly)..so there is little or no thread clearance.   When a little salt laden moisture gets in the area, the screws just lock in place.  The screws have 8-32 threads and it is pretty easy to snap off the hex head.   I use carbide drills to get the broken part out....it is a time consuming operation and the one thing you DON"T want to do is break off a carbide drill inside the screw.

There are some exceptions.......it appears that late replacement headlight motors were built differently......they either tapped the holes in the casting, used a different type of screw,  or possibly lubricated the screws.

Headlight motors with date codes a year or two later than the end of Reatta  do not have a problem with the screws breaking.   Unfortunately this is a small number of the motors I see.