Volvo RWD 700 Forum

Hi everybody,

Well, I made a rookie mistake on my 1987 740T. I changed the oil in the gear box (which was way past due). I put the bottom 13 mm plug back in. Then, I tried to remove the top 13 mm plug, which was rounded a slight bit. I couldn't break the plug free; so I thought, "No problem, I'll just bring out the vise grips." No go. The vise grip is just wearing away the brass nut. I tried a crescent wrench, pipe wrench, and vise grip again and again.

Any ideas? I'm thinking of drilling a hole and then using an EZ-out. But that EZ-out is hardened steel, and I suspect it will just eat right through the inside of that brass nut.

Before I drained the old oil, it was difficult to shift gears, even with the engine off. Now, with all the gear oil out, shifting is much easier.

But, I looked underneath the car and discovered I have a hydraulic clutch. Is there a way to adjust these? I see no adjusting nuts.

Hi,


Bleeding the clutch is the adjustment. Do it like a regular brake bleeding session.

Do you have a 19mm Six Point box end wrench? Go buy one at Sears. The largest Channellocks are the next option.


Goatman

Goatman,

Thanks. I also tried large channellocks, but that didn't work either.

Why a 19 mm six point box end wrench? I used a 13 mm 12 point box end wrench.

At this point, the nut is so chewed up, no wrench will probably work. I'll try again with the chanellocks in the near future. If that doesn't work, I think that maybe I can drill two holes opposite each other and use an old bicycle bottom bracket remover, which has two prongs.

Worst case scenario is drilling and chiseling the brass plug out.

Hi Fred,

I found that 19mm suggestion rather cryptic too.

Surely you want to try anything you can before drilling through the plug and infecting the lube inside. I have no experience with this particular plug, and I have this board to thank for that, because without having read someone's agonizing been-there-done-that warning, I'd have been right there with you learning the lesson firsthand.

Do you have a hand impact driver? Is there room for one if you did? Thinking heat, candle wax, and shock applied to a Dremeled slot that need not go through. In the plumbing section of the big box hardware retailers, they have thermal blankets for soldering copper pipes. I'm guessing the heat and mechanical shock will fracture the bond between the dissimilar metals. I don't know how the wax works, but I've been amazed by it on exhaust studs in alloy heads.

If no luck, and you wind up drilling through, will you pull the tranny to wash it out? I suppose brass turnings are better than steel.

P.S. It has been a while, but I recall the fill plug in my M46 was steel, 7/16 square drive. Could yours be a replacement?

--
Art Benstein near Baltimore

I had no Monet to buy Degas to make the Van Gogh.

Hi Art,

Top and bottom plugs are brass, so I think they're original (when I got the car). How does the candle wax work?

Your idea of heat is a good idea. I can try heating the plug with a heat gun. I don't have an impact wrench.

I should have first tried filing down the edges of the hex nut and then retrying using the 13 mm box end wrench, but I didn't.

No, I hope not to pull the tranny.

Thanks for your input.

Fredbyte,

You could fill the transmission through the shifter opening and leave the plug alone until such time you may need to remove the transmission.

--
Mr. Shannon DeWolfe -- I've taken to using mister because my name misleads folks on the WWW. I am a 53 year old fat man. ;-)

Shannon,

No luck with the bolt. I'd like to fill the gear box with oil so that I can drive down to a garage and have them work on it (probably welding something onto the bolt head). It would save me a tow.

I've stripped down the gear lever area and see a metal plate over the tubes. The metal plate has a circlip on the inside circumference. Do I pry that circlip open to expose the tube openings? Which tube goes to the gearbox? (I guess I can try to feel around there and verify.)

Thanks.

Shannon,

Thanks. I'm going to keep that in mind.

Hi Mr. Shannon,

Sounds like a been-there-done-that voice to me. Good idea!
--
Art Benstein near Baltimore

If you take a laptop computer for a run you could jog your memory.

A bit Cajun for sure, but probably the least amount of energy to get the same job done. Shine a flashlight into the hole and see if you can fill it to the low spot in the fill plug. My recommendation would be synthetic ATF.

I wish I knew the physics of the wax technique. Mostly the lore will refer to beeswax, though I just used a common birthday candle. The wax seems to wick into the interface just like a well-fluxed sweat soldering. I doubt a heat gun will provide the heat you'd need, and you might wind up cooking seals if you try to warm it up a lot - better a torch, oxy-acetylene or more conveniently, Mapp gas in a Bernz-O-Matic, so you can focus the heat and deliver it quickly and precisely before the tranny soaks it up.

An impact driver is a hand tool acquired by anyone with 60's era Japanese motorcycle experience. Sears has them. You strike it to rotate frozen fasteners.

The filing down and wrench resizing is a technique I've attempted to use on eroded exhaust system hardware; finding a wrench of any caliber to pound tightly over the bolt head. I don't recall having a lot of success that way, and mostly wind up getting out the cutoff wheel.

The pin spanner idea sounds good, if it was a bigger plug (with more span between the pins) otherwise I'd think it would be too weak to do the trick, and you still risk drilling through when you make the holes.
--
Art Benstein near Baltimore

When the smog lifts in Los Angeles, U. C. L. A.

Art,

Went to Sears and bought something called "Bolt-Out" by Craftsman. Too bad I bought it and used it at too late a stage for the hex head. I think it could have helped right away before I wore down the head. Doesn't work now. Anyway, I'm sure it works wonderfully for steel nuts and bolts.

Just want to clear up the technique on the heat. I can use a propane torch (plumbing). How long do I heat the bolt? Do I then tap the bolt with a hammer and then try to turn it while hot? Or do I let it cool somewhat and then try loosening it?

Also, for the wax technique, do I also heat up the bolt here and try to drip wax along the edges of the bolt and hope the wax gets soaked into the threads?

And, I have two more ideas. (1) Sacrifice my 13 mm box end wrench by putting it over the greatly diminished hex head (~10 mm now) and fill in the hole with something like JB Weld. Not sure if JB Weld "welds" together dissimilar metals such as steel and brass. (2) Or, try to have a friend come over and hot weld the wrench to the hex head. Will this last technique "melt" the tranny seals?

Thanks.

The wax techinique is actually best to do in combination with the heat and shock technique... you heat the plug as hot as you can with your propane torch (slightly glowing is best) trying not to heat the tranny cassing as much as possible, then you take a stick of wax from a long enough candle so that you don't burn yourself if the wax catches fire (I find a 10" chandelier type candle with wick removed works very well for this application) and press the wax against the hot plug cooling it rapidly (thermal shock). This will wick the wax into the threads and provide lubrication as you try to loosen the stubborn plug. Note: if the wax catches fire reheat a little less and try again because the wax will have burnt off and not penetrated the threads (this is unlikely unless you use and oxy acethelene setup and have the plug near its melting point + the point at which the wax cathches fire depends on the type of wax used in your particular candle)

If nothing works you can always do as I did and use a oil syringe found at most parts stores to fill your trany from the drain hole (just check for the amount specified in a repair manual or somone on the board surely knows what that amount is) ... you just have to be quick to put the plug back in after the syringes hose is removed from the hole. Once that is done and you have fluid in your trany go to a good repair shop which is equiped with welders and ask them to weld a nut or short bolt onto your plug and just replace it with a new one after its been removed.

The coefficient of thermal expansion of aluminum is greater that that of brass, depending on the actual alloy. I would assume the transmission case is some aluminum alloy. To help loosen the brass plug, you should actually heat the area around the plug, not the plug itself for best effect.

"The coefficient of thermal expansion of aluminum is greater that that of brass, depending on the actual alloy. I would assume the transmission case is some aluminum alloy. To help loosen the brass plug, you should actually heat the area around the plug, not the plug itself for best effect."
Yes and no, heating the case could melt or damage seals or even worst cause the case to crack (it is a casting after all) and using the wax method you are actually heating and then cooling the plug whitch expands the plug and then contracs it (cooling the plug with the wax) pulling the wax in the gap created in the threads.

"heating the case could melt or damage seals or even worst cause the case to crack"

Well, it really wouldn't need that much heat. But the wax method sounds intriguing. I've used a similar technique to loosen seized studs and bleed screws. Heat the culprit, then spray it with the penetrating oil of your choice.

One other method would be to use a pipe wrench with good sharp jaws. I can't believe that vise-grips didn't work, unless they were cheap ones or had worn jaws. I've used vise-grips to remove a theft-proof lug nut when I'd lost the key. Had to use a C-clamp to close the vise-grips and a big pipe, but it worked.