wvuguy

I was trying to change rear differential fluid on my 99 rx300 but the fill allen bolt was so rusted out that I ended up stripping it. Its pretty well rounded now. I have heard of people using torx bits or screw extracters. Any idea which one works better or if there are better ways ? I was able to losen the drain bolt with no problems (did not drain fluid out). Thanks.

salimshah

First of all pat yourself on the back for not draining without making sure that you can undo the filler bolt.

Which is better is based on what is available. I would invest time in applying penetrating oil ... you may have to soak a rag and tape it. Next would be using a jarring force to break the thread bonds. Heat is another thing you can use but make sure nothing catches fire ...

If you are willing to loose a tool, you can have it spot welded.

I would avoid anything that would introduce metal filings inside the diff. But when every thing fails, you got to do what you got to do.

You are lucky that you can drive it to a mechanic, if you decide to call uncle.

Last of all remember to buy a new plug.

Salim

lexus114

Definitely ^^^^^^

carguy07

You might be able to get a grip on it with vice grips. You could file the sides flat to help get some more bite.

Go underneath and look straight up at the inside of the hole for the Allen wrench. Most of the plugs on this car have an additional Allen or star type casting on the inside of the bigger Allen hole. I could be wrong, but it looks like the factory put them there as an out if you stripped the bigger hole. You can see what I am talking about in this picture. Anyone know for sure if that is what I am seeing or is it just part of the manufacturing process and just looks like another spot to get a wrench in?

sktn77a

iTrader: (2)

Looks like a small Torx head socket hole, but I'd be surprized if this will remove the plug when the larger allen wrench couldn't! It could be used as a starter hole for a "Grabbit"-type screw remover, though.

wvuguy

That looks like a torx head hole. I did not notice that before. As salimshah suggested, I will soak it well with WD40 first, tap it to break the bond and then try I will try losening with the torx bit. I will let you guys know. Thanks.

bob2200

Another thing I've done on bolts, to get a grip, is cut a slot with a dremel-tool cut-off disk and then turn, using the slot, with a large screwdriver.

trhs75

Excellent idea, and I would also agree about buying the new fill plug BEFORE starting in on the old one again. Good luck!

salimshah

I dont have an AWD. Depending on access and clearance, you can take a chisel and cut a notch at the edge and then place the chisel close to 90 degrees to the radius and whack it to undo it. [chisel and force, tangent to the outer edge of the plug].

Salim

wvuguy

I let the bolt soak in WD40 for a while and then tapped it with hammer to losen it. Then I tried using T55 torx bit which seemed to grip the stripped hole pretty good. I had to use a lot of force to turn it with a wrench but unfornately intead of losening the bolt it ended up stripping it even more. I tried vise grip but there simply isnt leverage and clearance to hold it tight. I will try the other ways mentioned in this post. If nothing works, I will take it to a local shop. Here is how it looks like right now.

code58

I realize you probably don't have one, but what I found was a life saver over the years for me in many different type of circumstances is a "panel cutter". It's an air operated sheet metal cutter, but has MANY different types of fittings that can be used instead of the sheet metal cutter. I even made some of my own out of broken SM blades. The one I would use on that (and have used effectively many times) is one I have sharpened to a point. I drive it into the flat surface around the allen hole at a 45 degree angle, counterclockwise. The "jarring" action will break almost any frozen fitting loose such as you have. Otherwise, when no danger of fire or heat damage, I use the heat of an acetylene torch to break loose, very effective!

Lexmex

That's actually an excellent idea. One other thing came to mind along similar lines that he might be able to try, though I think he'd need the heat of a torch.

If one were able to heat the end of a chisel enough, (I don't think a screw driver would do it), one might be able to drive (via the heat) into the edges shown below and make an indentation. Then, one could put screw drivers into those indentations and turn the bolt in a counterclockwise direction to get the bolt out.

wvuguy

Lexmex,
Wouldnt it be hard to turn it with a screw driver when I couldnt turn it with a socket wrench with a fairly long handle (high torque)? Unfortunately I don't have a torch or other tools mentioned above. I am gonna try salimshah's suggestion of putting a chisel at a tangent and hitting with the hammer to move it counter clockwise.

salimshah

Also try a little more potent penetrating oil like liquid wrench ... Keep in mind that LW is much more flameable than WD40.

Use a 4lb hammer if you can to jarr it and to pound the chisel. Lesser weight and you do surface damage only.

It all depends upon clearance(s). Or give a mechanic $10 instead of investing in extractor tools.

Salim

Lexmex

You'd have one screw driver on the top and on the bottom, on the top you'd insert and pull counterclockwise and on the bottom you'd insert and push counterclockwise. The key would be to get the screwdriver in there deep enough.

Salim's method would also be good to try (didn't think of that).