Replace throttle position sensor on 1991 Lincoln TC

I am trying to replace my throttle position sensor (TPS) for my 1991 Lincoln Town Car. Of course the TPS is the same for many model years and many Ford brand names. The air duct channels up to an aluminum housing w/the mass air flow valve & sensor. The TPS is attached to this aluminum housing w/2 Phillips (#2's) head screws that are about 1 1/2 inches long. My issue is that these two simple screws are "frozen" in place.... I have tried liquid wrench...WD40...heat...etc....still "frozen"...I think that the aluminum body housing has oxidized the metal screws...

Anyone ever replace their TPS ??? How did you or your mechanic over come the issue I have described ???

Depending on how long it was that the metal screws have been in (and if this is the OEM from the factory), the oxidation from the aluminum body will "freeze" them in. Liquid Wrench soaking is about all you can do, except to use a stout screwdriver to get them out. (Never use those cheap $1 screwdrivers you find at the front rack at the auto parts house. Always buy good tools.)

Keep constant pressure on them. Try tightening them first, then loosen them up. If the head slips, you are in a world of hurt getting them off. Also try giving them a tap with a hammer with the screwdriver on it.

I've even put small parts like a throttle body in boiling water for a couple of minutes before starting heavy handed work. Sometimes the heat will swell the part enough for the metal screw or bolt to break loose.

Hey jdmeaux: Thanks for the suggestions...I have been thinking along the same lines...

I have a few heavy duty...long handled screw drivers that will give leverage to the screw head...except I don't have one w/Phillips head....

I applied heat w/electric hot air pistol blower...but no go. I am about ready to take the aluminum housing off for more considerations....yours w/boiling water.... I might try CLR and/or vinegar....maybe heated vinegar...

If these attempts are not successful or I 'strip the Phillips heads'....I may have to engage in a drill press process....slowly & carefully....a drill out.... Not looking forward to doing that...but I have had to do that on some control arm bolts/pins are have gotten "rust frozen' into place so tight that nothing would free the unit. I have read about a electrical thermal heating bolts & nuts rusted in place (electromagnetic induction heating... ) but I can not use anything like that in this application because of the TPS is in a hard plastic housing....It couldn't handle a red hot heating process....

( I wished I had know about this process & could have afforded the thermal tool for the bolt & nuts w/out a plastic...rubber...or other damaging issues... )

I''m still searching & thinking of alternatives....!!!

I had a few photo shots (img's) but I just deleted them before getting the transfer from the camera to the file folder....I'll try to get "new photo shot" before the coming sever winter weather storm starts hitting tomorrow morning...hoping we don't get what's being forecaster....