Broken bolt/cant weld or heat it

[AK_Willy]

Broken 5/16" reverse thread bolt in a $2000+ exercise bike. I took bolt off due to wobbly crank arm. It had blue loc tite on it.
Used a cobalt drill but, then stupidly put an extractor bit in, and cranked to the left. Snapped off. Lesson learned.
Next step? Drill again, tap and bolt and I'm going to remember to go right to loosen.
The loctite isn't helping anything. Any tips would be great. No welder, and delicate electronics are in those area.

 

[Kuma601]

Call the parts dept for that exercise bike and get a new spindle and crank arm bolts. Will save you lots more time than trying to extract that sheared bolt.

One bad part about stationary bikes is that the sweat that drips into the crevices makes rust a big PITA. A coating of grease and annual or semi annual maintenance to keep stuff from rust welding together is good practice.

 

[AK_Willy]

Support and parts for this bike ended some time back, if my research is correct. I do appreciate the input !

 

[KEH]

Can you heat the area with the loc tite? If so, heat should loosen the loc tite.

KEH

 

[jstroede]

I would design and 3D print a guide to use to drill it centered and square and use a carbide bit to drill it out. Carbide should cut right through the extractor.

 

[nadogail]

A Right Handed,(normal) Carbide or Cobalt Drill bit may be your answer.

Heat, Pressure and Vibration will be your friends in getting the bolt to move.

 

[Walkers]

Why can it not be welded or heated? (Edit) I see you dont have a welder. This is an excellent excuse to buy one. Otherwise just take it to a welder, that is an easy removal.

 

[Hank11]

Is the thread left or right handed?

 

[Pontiac787]

These are the options I would try, and in this order.

1) Try wacking the edge of the bolt with a punch in the direction you want it to spin. Move around the bolt.

2) Drill out the extractor, if you can, and try again.

3) cut a groove with a grinder and try to move it with a flat head screwdriver. Impact driver if possible.

P.S. - I don’t see blue loctite causing any major concern.

 

[PugetDude]

^^#3 for the win^^

 

[whateg01]

Is that BB standard or is it specially made for the exercise bike? I would think they would use a standard BB to keep costs down. If that's the case, it should be pretty inexpensive to just replace.

 

[Beauregard]

I've had luck using the tip of a soldering iron to heat the bolt in sensitive areas.

 

[whateg01]

Looking closer, it probably isn't a standard BB, but it uses generic metric deep groove ball bearings, so I wouldn't be afraid to just drive the whole thing out with a hammer and take it to a machine shop and let them deal with it. The bearings are v cheap and readily available.

 

[Youngandfree]

Support and parts for this bike ended some time back, if my research is correct. I do appreciate the input !

It's probably not worth $2000 anymore if you can't get any support or parts.

 

[Old tool guy]

These things have pretty small flames.

 

[BillK]

Once you broke of the extractor you rea lly made the job next to impossible. Where do you live ? Se if there is a machine shop around with a "metal disintegrator" edm machine. They should be able to get it out.

Either that or take it to a muffler shop and have them weld a nut on it. Once they do that it will probably almost come out by hand.

 

[Kuma601]

The arm is off so removing the spindle assembly should be simple. Once out of the frame a variety of extraction attempts can be made. As well finding compatible parts to swap in. What brand and model is this?

Convert it over to something that common parts are readily available:

Amazon.com : square taper bottom bracket

I replaced a square drive spindle on a 70's Sears exercise bike with a Shimano spindle from the 80's. Same BB shell that finding stuff from the bearing shop and old bike shops was easy. eBay has lots of stuff too.

 

[tarmy]

I have had to do that exact fix on my exercise bike…no longer supported. Mine sheared from fatigue.

I removed the shaft and did my fix in a good vice on the bench.

As mentioned… center punch and cobalt drill. I eventually got mine out in pieces and the threads were goobered up. I had to buy a left handed thread tool bit and carefully re threaded the new slightly bigger hole. Bought a new bolt online (metric lefty) and it has been used for 5 plus years…nearly 4500 miles per year!

Go slow and use some heat if needed. Mine did NOT have any locktite. If needed, pay somebody with a good lathe to do the drill out and re thread. Hell, somebody here may be able to do it.

 

[aafadca]

I had pretty much the same problem with an old riding mower engine exhaust. luckily it was off the mower so I tried different things, welding a nut on stud (stud broke off flush), drilling (bit broke!), took it to a mechanic shop (no luck). Finally took it to my old high school machine shop. They were able to somehow machine it out. So if you no other way works find a machine shop. They should be able to do it.

 

[AK_Willy]

These are the options I would try, and in this order.

1) Try wacking the edge of the bolt with a punch in the direction you want it to spin. Move around the bolt.

2) Drill out the extractor, if you can, and try again.

3) cut a groove with a grinder and try to move it with a flat head screwdriver. Impact driver if possible.

P.S. - I don’t see blue loctite causing any major concern.

I'm gonna give #3 a try. I've got a few rotary tools, just need to grab the correct wheel, to cut the groove. Thanks for the ideas!

 

[scooby074]

You could try a carbide burr in a die grinder.

But that is the perfect job for a tap disintegrator. Literally what they were made for. Call around and see if any machine shops around can offer the service (and how much $$$). Id do that before digging much deeper and making a bigger mess.

 

[jonesg]

$60 at a machine shop to rescue a $13 bracket.
tough decision.

https://www.amazon.com/dp/B08C786DW8/?tag=atomicindus08-20

 

[jar944]

Once you broke of the extractor you rea lly made the job next to impossible.

You can grind them out with a diamond or carbide burr.

 

[73project]

I would be using Pontiac787's trick #3 with a thin kerf cutoff disk. Cut a groove through the bolt and the easy out that is deep enough to get a good bite with an impact screwdriver. Apply some heat to the shaft and then set the impact screwdriver to rotate clockwise when struck. I've removed many motorcycle covers and and buggered bolts using these impacts.

 

[jkuro]

I've done this. Use a small drill bit and very carefully drill around the circumference of the broken extractor. Keep at it untill you can pick the broken extractor out. Very tedious but it works. Now try a new extractor, be sure to turn this one clockwise.

 

[My Old Tools]

Grind the slot and use a hand impact driver and hammer.

 

[Kuma601]

Most these manufacturers didn't use propriety parts. If the exercise to save and use the original part is more of the challenge go for it.

If this is a gym level fitness spinner, parts exists from a variety of supply places. eBay is a good resource too.

 

[AK_Willy]

The arm is off so removing the spindle assembly should be simple. Once out of the frame a variety of extraction attempts can be made. As well finding compatible parts to swap in. What brand and model is this?

Convert it over to something that common parts are readily available:

Amazon.com : square taper bottom bracket

I replaced a square drive spindle on a 70's Sears exercise bike with a Shimano spindle from the 80's. Same BB shell that finding stuff from the bearing shop and old bike shops was easy. eBay has lots of stuff too.

After re-reading, this makes perfect sense. Time to stop drilling and beating on this part, and remove it for measurements. The bearings have to be common as mentioned before. Replacing it would make the most sense, and as you said, fixing this part will be alot easier if removed first.
Bike is a Pro-Form TDF Pro 4.0
Seems discontinued now but was $3K.
Thanks for the tips. Crank axle and bearings coming out Monday for sizing!

 

[drmarkr]

Google that model and "bottom bracket"......you'll find parts are available. And even vids on replacing them. Not sure if this is your model, but these parts are not unique to exercise bikes.