Anyone know how to remove a seized bolt? I have a bolt directly threaded under the bottom bracket shell that is holding the plastic bottom bracket cable guide. I've tried everything. Water, WD40, but I cannot remove it. It is really stuck in there. Any ideas?

i use a product called Reducteur H-72, industrail commercial grade.... dunno if its available in your location

helps release rusty nuts and bolts, in 30 seconds, it really does the trick {every time!

Two other products that are more available in the US are PB Blaster and Kroil. You did not mention your frame material. I will assume it is metal. Spraying this on the outside may help you out. I think your best bet would be to remove the bottom bracket and spray the oil on the other side of the screw. This will get the fluid into the threads.

If the screw extends into the bottom bracket I would grind off the rusty bit that sticks out.

If you have stripped the head of the screw you may have to use vice grips to grab the head. If that fails you may need to drill out the screw. Start with a small drill perfectly centered and work up very slowly. Hope this helps.

Ride Safe,

Joe

Lots of penetrants out there that will do the job, water and WD40 are not one of them, it helps to tap on the stuck bolt to help the penetrant do it job and get into the threads.

P B Blaster!! Just started on an older frame and it works great!

A manual impact driver will work. It's a brute force tool I'd usually not use on a bicycle but for the screw that holds on the cable guide, it'd be okay. It's cheap and a tool worth keeping in your toolbox anyway.

Impact driver - Wikipedia, the free encyclopedia

Best I have ever used:

LPS Labs 01916 LST Penetrant - 11 Oz. Aerosol Can - VV-P-216C at SkyGeek.com

Drill it out? The location suggests that a slightly larger, replacement, screw would go unnoticed.DELRON UNDER BOTTOM BRACKET GUIDE :: BRAZON/SMALL PARTS :: Nova Cycles Supply Inc.

Try a 50-50 mixture of naptha and automatic transmission fluid. Give it a little time to penetrate.

First question: have you broken away the cable guide so that you can just grab the screw with pliers? Are you trying to salvage the cable guide? They are less than $1- each if you purchase dozen; $5- or so each at the LBS. Chemicals (as listed in the posts above) that are effective on helping getting the screw out will damage the cable guide.

An impact driver will dent the BB shell; which will be difficult to repair.

Using a drill to remove the head of the screw, which will then allow removal of the cable guide, followed by pliers on the remains of the screw will be effective. New screw required.

In addition to Nigel's excellent advice, I'm surprised that no one has suggested using heat. You don't need a blow torch to apply a bit of heat to the part, though it would certainly be effective. Just touch the head of the screw with a soldering iron and let a little heat penetrate the bonded parts. Watch out for flames if you're using solvents around hot tools! YMMV.

Hi guys. Thanks for your great advice. The suggestions were fantastic and I was able to get the bolt out not long ago. I think all of the suggestions would have worked fine.

I was just about to head to Home Depot and look for some bolt penetrant such as Liquid Wrench, but thankfully I didn't need it. In the end what worked best for me was a hammer and some vise grips. I sprayed some WD40 on and inside the BB she'll and let it sit overnight. Its true that WD40 isn't a bolt penetrant and not as effective as the other bolt penetrant a mentioned, but I had some lying around the garage. I came back in the morning and turned the frame upside down and hammered lightly on the bolt head to try to maybe break any time rust that may have been covering the threads. Then, instead of using the screwdriver, I used some vise grips as were mentioned by some users here. There was just barely enough of the bolt head sitting on the plastic cable guide that I could clamp on to. I clamped on to the bolt head very tightly with the vise grips and did a couple turns. And voila! The bolt started to turn. Joy! Thank you again everyone!

Liquid nails is glue.......

Oops! I meant the Liquid Wrench product, not Liquid nails. I made the edit above. Sorry. Thanks everyone for the great advice!

I'm not a bike mechanic but I slept in a cheap motel.
If you use Kroil, heat & cold with a firm smack from time to time with a well fitting screwdriver or pin punch and hammer it works every time.I remove 100 year old bolts all the time this way.Most times the bolt or screw is saved as well.It may take a day or a week but works without drilling and possible damage.

I restore 70's and 80's motorcycles so I often run into frozen fasteners. Here are some things to try (usually in this order):

Allow PB Blaster to soak and tap with a hammer

Apply heat

Use an easy out (with reverse drill bits)

Weld a washer on to fastener (or what's left of it) and weld a nut on to washer giving u extra leverage

Sometimes it helps to alternate between loosening and tightening directions. I've had some incredibly tight bolts that first moved in the tightening direction, then came out.