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This weekend I'm helping to upgrade brake pads and rotors on a '95 NA so am expecting more than a few issues with the slider pins which I suspect haven't been attended to since the car was rolled out of the factory.

I've got a few penetrating oils that I've used in the past but came across the "50/50 AutomaticTransmissionFluid+Acetone" option on a Jeep forum today which looks to be worth a go:

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"The April/May 2007 edition of Machinist's Workshop did a test of penetrating oils where they measured the force required to loosen rusty test devices. Buy the issue if you want to see how they did the test. The results reported were interesting. The lower the number of pounds the better. Mighty interesting results for simple acetone and tranny fluid!

Penetrating oil . Average load .. Price per fluid ounce
None ................. 516 pounds .
WD-40 .............. 238 pounds .. $0.25
PB Blaster ......... 214 pounds .. $0.35
Liquid Wrench ... 127 pounds .. $0.21
Kano Kroil ........ 106 pounds .. $0.75
ATF-Acetone mix.. 53 pounds .. $0.10

The ATF-Acetone mix was a 50/50 mix (1 to 1 ratio)."

Personally, I've used the ATF-Acetone mix and had very good results. I believe that what's happening is that the acetone breaks down the surface tension of the ATF which allows it to penetrate into the threads. Then the acetone evaporates, leaving the ATF to break down the rust a bit and act as a lubricant.
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Anybody else used this solution before I try it tomorrow?

They shouldn't be that bad to need any penetrating oil.

Also remember, when you brake there's a lot of heat generated, so there might be a fire risk (not sure on ATF, but acetone certainly!)


I think you'd be better off just using the proper high temp grease.
it's not that expensive.

Soak them with a penetrating oil and press them out with a 'G' Clamp and a piece of tube. The pins will not fall into you hands but as Nick says they should not be too stubborn.
Greg.

hks_kansei wrote:They shouldn't be that bad to need any penetrating oil.

Also remember, when you brake there's a lot of heat generated, so there might be a fire risk (not sure on ATF, but acetone certainly!)


I think you'd be better off just using the proper high temp grease.
it's not that expensive.

The penetrating oil is meant to allow the potentially rusted pins to be unbolted and removed, NOT as a slider pin lubricant - I'm a bit paranoid after stripping the head of an endlink once (and bending the spanner).

The acetone will evaporate long before the car is rolling again.

Ahh, sorry.

I was mistaken.

I thought you wanted to use it instead of the grease.

My mistake.

Just an inference, but if acetone breaks down ATF to make it less viscous, then would it be a fair assumption that mixing acetone with a lighter grade oil make an even more penetrating substance?, Or is acetone so strong that it needs the viscosity, and inherent chemistry, of ATF as a "base" otherwise it will just break the lower vis oil too easily?

I've not come across many seized bolts and have used Lanotec (lanolin) stuff to pre-empt any bastard bits.