Good afternoon all,

First time posting here but have viewed the forum for quite some time since I got my 1997 XK8 coupe last year. Unfortunately I may need some guidance and wisdom. I changed the Diff oil using the "drill a 2 inch hole in the rear" method and all went well until I tried to reinsert the diff plug. I found it very difficult to insert it due to the brace that the plugs sits behind and I fear i may have cross threaded it. It only gets a third of the way in and then tightens so I dont want to force it for fear of making the situation worse. No matter how i remove it or reposition it always binds at the same point. Any guidance and idea on how best approach this? I feel I need to get at the plug by installing it straight in rather than trying at an angle on the end of a wobble attachment, but the suspension cross member prevents this. Is this easily removed at all or any other ideas on possible solutions?

Thanks so much
Richard

 

I assume from the rust marks that the plug was further in than that before? I recall that it is a taper fit so never goes all the way in.

Does it get the third of the way in just using the extension bay without a ratchet handle on the end and has it always done that since you first tried? If that is the case and you only need to use the handle after a third then I doubt it is cross threaded. Have a look from underneath with a torch. It's a coarse thread so if it is cross-threaded it will look visibly out of alignment. Tapered fittings usually do up very easily by hand and then suddenly go tight.

This is from a previous post of mine "I found that the best way to get the plug in and out was to use a 10 inch 3/8 extension wobble bar with a 3/8 to 1/2 inch adaptor on the end. The 1/2 square then fits into the plug. I first tried it just using the 1/2 inch wobble extension on its own but the drain plug points slightly downwards towards that cross-piece and I just couldn't get the angle right because the 1/2 inch bar is slightly too thick and bears on the cross-piece which forces it out of line."

 

As RichardS says, It's likely okay, since it's a tapered pipe thread. I don't think it would go in that far if it were cross-threaded.Wrap some Teflon pipe tape on the plug if you're not sure it's sealed.

 

Richard, I thank you for your response and it made me take a closer look at the plug and you are indeed correct. There is a definite rust patch marking where the plug used to sit before I removed it that I had not noticed. When I put it back in, it binds at this rust line. I do still feel however that it should seat further in, and i have only now noticed a gouge mark in the threads on the plug, potentially from the past owner so I will replace this plug as a precaution. But hopefully the threads in the diff themselves remain in a good condition. Thanks for your suggestion!

 

[Sarcasm]In practice, disposables are made of the cheapest material available, like soft, pliable carbon steel, while durable parts are made of more noble materials like hard, permanent Aluminum. One of the many joys of doing our own work. [/Sarcasm]

 

Reality, not sarcasm

 

I had this on mine with damaged threads in the aluminium so I turned a few threads off the end to give a guide... Coat with epoxy enter it in and check from below its square then tighten as much as you dare ....Not the best solution but what else can you do.

 

Hey don’t panic, I got a simple solution that worked for me recently. Last month I did the drill a 2” hole method(I did 2.5”) but i faced the same dilemma when trying to refit the plug. To remove it I bout a set of “wobble” extensions from harbor freight that worked great. But found upon trying to refit plug that Erie sense of “am I cross threading it?” So here’s what I did;

1. Took the plug over to the bench grinder with a wire wheel and cleaned up the corrosion on the threads real nice.
2. I took a retractable magnet(like for fishing out dropped bolts and such, I’ll post a pic if I can) and extended the first few parts.
3. Taped the sections with electrical tape to keep them from spinning.
4. Stick the magnet on the plug inside the square drive hole and carefully start the plug in the hole.
5. After a few turns, When the plug reached the resistance and the magnet started to spin on the plug, switch back to the wobble socket and carefully tighten it up.

this allowed me to go by feel to get the plug started, but if I had it wrong the magnet would spin and I would start over. Give it a try

 

 

The critical bit is before you apply any real torque go underneath as see if it looks aligned . the adjust or tighten

 

Thanks all for the responses. Since I have installed the plug I have been monitoring it and its holding solid with no leaks or weeping so I am confident that its in enough to do its job. Appreciate the assistance.