Rusted/Worn out bolts

[karan733]

I need to raise my saddle height but the bolt is completely worn, and the allen key doesnt have anything to grip. Is there a way of getting the old one off or adjusting the saddle?

Also, are rusted bolts a hazard? I have noticed the bolts in the brake calipers have rusted over after the recent rain, will they have become too brittle and split under heavy braking?

 

[battered]

I need to raise my saddle height but the bolt is completely worn, and the allen key doesnt have anything to grip. Is there a way of getting the old one off or adjusting the saddle?

Eurgh, can be tricky. If the Allen key hole is worn you need a screw extractor or in bad cases to drill out the offending item. I'd take it to a shop if I were you and replace it as unless you know what you are doing you can spend a lot of time making a mess of it.

Also, are rusted bolts a hazard? I have noticed the bolts in the brake calipers have rusted over after the recent rain, will they have become too brittle and split under heavy braking?

No. For proof look under any car over 5 years old.

 

[hubgearfreak]

I need to raise my saddle height but the bolt is completely worn, and the allen key doesnt have anything to grip. Is there a way of getting the old one off or adjusting the saddle?

yes, go to a proper tool shop (not B&Q) and buy the size of torx bit (pictured below) that will need a bit of hammering in. then extract the old bolt and fit a new one.

 

[karan733]

yes, go to a proper tool shop (not B&Q) and buy the size of torx bit (pictured below) that will need a bit of hammering in. then extract the old bolt and fit a new one.

Right, im being daft - how will this work if the allen hole has been rounded off?

 

[accountantpete]

Personally I'd either get a hacksaw and cut a slot to enable a flat headed screwdriver to work or simply cut the bolt in the middle.

 

[tyred]

Right, im being daft - how will this work if the allen hole has been rounded off?

The Torx bit will be slightly larger than the allen key so when it's hammered in the splines will grip the head of the bold and unscrew it. It's called an "interfernce fit."

 

[Rob3rt]

2 DIY options imo.

Coming from experience working in heavy industry for a total of 12 months (during summers while doing my undergrad degree) as a machine technition, if a bolt would sheer, we would try 2 things before drilling it out.

1) Get a centre pop, smack it in at an angle off centre and keep tapping it, hoping that it gets enough grip to turn the bolt enough to loosen it.

2) Get a screw extractor, smack it in, then turn the bolt out, if this failed or didnt fully extract, drill a bit bigger and use next size screw extractor, until the bolt was out. If no luck, drill that sucker out!

 

[battered]

Right, im being daft - how will this work if the allen hole has been rounded off?

This *does* work, it's one of the engineering options I talked about when I suggested taking it to a shop. I've used it and it works a treat. Truth be told though, if you don't already know this, leave it to a nman who can.

 

[delstron]

Just going to a shop when we have a problem does not help learn to master these tecniques and improve our skills. I would suggest Hubgears reply is the most sensible, get a torx bit and drive that in. Application of penetrating fluid in advance will help things along.

 

[battered]

It depends on your skill level though. If you are coming at this with decent engineering knowledge then yes, by all means use a Torx as a screw extractor. If however you are a novice mechanic you are likely to waste your time at best and bugger something else at worst.

These days I can tackle pretty much anything on a bike. A few years back I couldn't and I managed to cross thread a cable adjuster on a derailleur. I had the good sense to take it to a shop where they cleaned up the thread with a tap and fixed it. It's still running today on the commuter. Had I persisted I'd probably have buggered it completely. I'm all for learning the skills but you need to walk before you run.

 

[PpPete]

I'm reasonably mechanically minded..... but all my best learning experiences have been as result of really stoooopid mistakes. Some of them so embarrassing that wild horses wouldn't drag them out of me.

 

[guitarpete247]

As has been said earlier a screw extracter would certainly get your bolt out. Liberal use of penetrating oil to break the rusts hold to start with. Screw extracter are not too expensive. This set from Screwfix is only £2.96 for a set of 5.

 

[tyred]

It depends on your skill level though. If you are coming at this with decent engineering knowledge then yes, by all means use a Torx as a screw extractor. If however you are a novice mechanic you are likely to waste your time at best and bugger something else at worst.

You're probably right, but, it's the only way to learn and the best lessons are often learned from your mistakes.

I would always encourage anyone to have a go.

 

[hubgearfreak]

It depends on your skill level though. If you are coming at this with decent engineering knowledge then yes, by all means use a Torx as a screw extractor. If however you are a novice mechanic you are likely to waste your time at best and bugger something else at worst.

your definitions and mine differ enormously. if the OP had decent engineering knowledge, then they wouldn't be asking the question. if the OP is a novice mechanic, then ask the question and proceed to have a go on the concensus of opinion.
if the OP is the sort of person, ie. incompetant enough to cross thread a cable adjuster, then you're probably right about leaving it to the shop

 

[Crankarm]

It depends on your skill level though. If you are coming at this with decent engineering knowledge then yes, by all means use a Torx as a screw extractor. If however you are a novice mechanic you are likely to waste your time at best and bugger something else at worst.

These days I can tackle pretty much anything on a bike. A few years back I couldn't and I managed to cross thread a cable adjuster on a derailleur. I had the good sense to take it to a shop where they cleaned up the thread with a tap and fixed it. It's still running today on the commuter. Had I persisted I'd probably have buggered it completely. I'm all for learning the skills but you need to walk before you run.

+1.

A little knowledge is a dangerous thing.