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Discussion Starter #1
took car in to have snow tires/rims put on. one tire came off fine. other 3 the mechanic showed me where the lugs would come out so far, and then stop. he would not force out, as said they were stripped. is it liekly the lug bolts, or the actual threads on the hub?

suggestions? bad personal economy, so am trying to figure out in advance of a mechanic visit specifically what may be wrong and if i can personally remedy .....

(if it matters, the tires coming off are 17inch rims/tires. the snow tires going on are standard mb rims and snow tires. i purchased all through luke at tire rack, so i know they are all correct sizes, etc. have come off and on several times with no problems. in reading threads, it is probably that they were tightened with air gun?)
 

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took car in to have snow tires/rims put on. one tire came off fine. other 3 the mechanic showed me where the lugs would come out so far, and then stop. he would not force out, as said they were stripped. is it liekly the lug bolts, or the actual threads on the hub?

suggestions? bad personal economy, so am trying to figure out in advance of a mechanic visit specifically what may be wrong and if i can personally remedy .....

(if it matters, the tires coming off are 17inch rims/tires. the snow tires going on are standard mb rims and snow tires. i purchased all through luke at tire rack, so i know they are all correct sizes, etc. have come off and on several times with no problems. in reading threads, it is probably that they were tightened with air gun?)
From personal experience on my W126, I'm going to say it's the threads on the hub. You will need a tap and die set; they are cutting tools used to create screw threads in solid substances like metal. A tap is used to cut the female portion of the mating pair (e.g. a nut). A die is used to cut the male portion of the mating pair (e.g. a bolt). The process of cutting the threads in a hole is called "tapping" the hole. The process of cutting with a die is called "threading" (or sometimes "chasing", although "chasing" as a technical term can have restricted meanings).

(...From Wikipedia, the free encyclopedia...)
 

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If you're going to go the route of personal fixin', allow me to suggest a few things that will be money well spent. First would be a quality tap fluid such as Safe Tap, which has a low viscosity, and a heavier tap fluid such as Rapid Tap, which has the consistency of honey- very high viscosity. More on these later. Everything including the tap and handle should cost ~$60, the tap being the most expensive thing.

When you go to remove the lug bolts, crank them out as far as they will go with moderate force, don't hulk them out or use excessive force- delicately like the mechanic was doing. When they reach that sweet spot and won't turn further, use the lower viscosity tap oil and squirt some deep into the recess and try to get it on the exposed threads of the bolt. Crank the bolt back into the hole, and attempt to remove again/ repeat with the oil. Use a sensitive touch to 'feel' the threads; you don't want to strip anything.

If you manage to get the bolts out, you probably want to chase the threads (as stated above) with a tap. Never skimp out on quality cutting tools- it's better to have a single tap of high quality than a set of cheap useless taps. Purchase a Dormer, Tungaloy, Clarkson-Osbourne or Chicago-Latrobe tap- these are industrial grade tools and will cut to the exact size and thread form you want. The tap size for your lug bolts is 12 x 1.5, which is metric of course. That just means it's a 12mm thread diameter with 1.5mm between each thread. Industrial supply houses will have these in stock; for example, locally we have Brafasco (pretty $$$) and Fastenal. Get a normal 4-flute straight tap; no spiral or helical flutes- they're used for power-tapping on machines and will do no good by hand.

Whilst chasing the threads (you'll need a tap wrench now, borrow or purchase one when you get the tap) make sure the tap goes into the hole squarely. It takes some finesse to use a delicate touch and be sure the tap engages on the thread properly. Keeping the tap square is a sure way to do this correctly, the last thing you need is to cross-thread the lug bolt hole.

Oil the tap, using the honey-like oil now (which is much better for chasing threads, and the viscosity keeps any chips produced stuck to the tap when it's withdrawn) and turn it a couple threads and then reverse. One step forward and two steps back when tapping; the withdrawl breaks any chips made in the hole and prevents the tap from snapping on you. A good word of advice: if it feels like it won't go anymore, don't. Reverse and try again lightly (never "spring" or "bounce" a tap- slow steady turns), and if not, the hole's done. You'll only need to go about 1/2"-3/4" up the threads of the tap to chase the entire hole.

Inspect the threads prior to and after tapping with a penlight to make sure they look unified and continuous, and to be sure there are no obstructions in the hole.

Worst case scenario, if one hole is really buggered up you may be able to get someone or DIY to install a lug stud into that particular hole. Blowing everything out with compressed air works very well.

Check all your lug bolts for thread consistency as well. If there is any doubt, purchase new bolts, they're not too horribly expensive. Chasing the bolts with a die isn't worth it, and if we want to get super-technical, most dies will cut 0.002"-0.003" smaller than the original bolt thread which will make for a sloppy fitment in the hub.

Sorry about the long post, hope it helps. Smear a very tiny amount of anti-sieze on the bolts when they're renewed, and hope none of this situation is ever repeated.

(On Edit) Get a regular flat tap handle, and not a T-handle. The flat handles offer more torque and shorten the whole assembly making it somewhat easier to line everything up.
 

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Discussion Starter #4
Question: I'm preparing to retap the threads, but have conflicting info. The answer above says get a tap that is 14X1.5, but I was just told by retailer that the bolts are 12X1.5. Can someone clarify for me?
 

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Discussion Starter #5
ignore quesiton above. they are 12X1.5. I was finally able to get the drop down box for the search. Which leads to another question -- Why is the Search drop-down not working very well lately? Me or others too?
 

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If you are running alloys and going to steels the wheel nuts will be to long and fowl the park break..
 

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Discussion Starter #9
Hi Prodigy, I did not mean to draw attention to a typo. I am attacking this tomorrow, Saturday. I'll update as to difficulty for a novice.

Prodigy, I greatly appreciate your time in writing out the directions above.
 

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Haha, no worries! That's the beauty of text, there's plenty of room for interpretation. I took no offense at all, rather, I appreciate that it was corrected!

Best of luck doing the work; it's not difficult really, just requires patience when cutting threads.

As an aside, and as Joe has already brought attention to, the alloy bolts are about 10mm longer than the bolts for the steel wheels. They're not interchangeable.
 
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