Bottom bracket removal tools...advice and help.

So

As expected after a few hard rides my newly acquired Team Marin is making grumblings from the bottom bracket. As far as I can tell its a Shimano M730 XT BB (91-93). A couple of questions really as I have not had this style of bb before so none of the relevant tools!!

- What tools would I need to remove it? Are there any brands better than others I would rather buy good tools and pay a bit more than the budget if it makes the difference.

- I assume that each side unscrews clockwise? Is there a good technique which side first?

- If I managed to get inside and find the bearings need replacing...assuming the cups are ok, what size bearing race do they take or bearing size and number or is it just a case of new BB?


See pics below for BB style

Thanks in advance

Wook

I would remove the existing BB and replace it with a modern cartridge style BB.

Shimano UN54 or 55 are pretty cheap, smooth and last for ages: http://www.chainreactioncycles.com/Models.aspx?ModelID=71369

You can get special tools remove the existing BB, but they won't be any use for cartridge style BBs:

http://www.chainreactioncycles.com/Models.aspx?ModelID=42802

http://www.chainreactioncycles.com/Models.aspx?ModelID=13228

You might be able to "bodge out" the existing BB by knocking round the lock ring with an old screwdriver and a hammer, you can sometimes also get the cup out with an old screwdriver and a hammer as well. The cup with the flats on can be removed with a large adjustable spanner.

You'll need a tool like this: http://www.chainreactioncycles.com/Models.aspx?ModelID=689 to install the new cartridge style BB, or you can get ones with a handle on, so you don't need a large spanner.

...so it might just be worth going to the LBS to get them to remove the current one and then replace with a cartridge style and get the fitting tool for that? Is it a case of if the bb is noisy its not worth reparing? Seems a shame as its an old XT one and original spec...

hi wook.

the threads are what you'd expect. non-drive is clock-wise in and anti-clockwise for out.

drive is clock-wise for out..vise versa. japanese industry standard aka.

a 36mm headset spanner will sort the drive side(two flat sides).

for the drive...a lockring spanner and a pin spanner would be the 'normal' providing your cups are not too stubborn. the main cup and lockring are threaded the same way, the lockring bites on the bb shell to lock it all up.

this for lockring.
http://www.ebay.co.uk/itm/COMBO-CYCLING ... 416c5ffd29

this for 6 hole cup.

http://www.ebay.co.uk/itm/Park-Tools-SP ... 43b60c883d

once you're in see how your bearings look. most likely in a race or can be loose. XT headsets are loose on the lower race on some models. either way take a sample to lbs.

thats the right way, drive side is installed until snug against shell where t'other side is adjusted like a headset, smooth but snug etc...

now, i remove these 'my way' as i replace with a sealed unit, so dont have any inhibitions on using a hammer, scredriver, mole grips etc..

yours is a good bb and worth keeping in.

cheers.

wookiee":1h3hmp0l said:

So

As expected after a few hard rides my newly acquired Team Marin is making grumblings from the bottom bracket. As far as I can tell its a Shimano M730 XT BB (91-93). A couple of questions really as I have not had this style of bb before so none of the relevant tools!!

- What tools would I need to remove it? Are there any brands better than others I would rather buy good tools and pay a bit more than the budget if it makes the difference.

- I assume that each side unscrews clockwise? Is there a good technique which side first?

- If I managed to get inside and find the bearings need replacing...assuming the cups are ok, what size bearing race do they take or bearing size and number or is it just a case of new BB?


See pics below for BB style

Thanks in advance

Wook

Click to expand...

Is the noise a creak or a crack? creaking can often be caused by loose cranks, crank bolts, chainring bolts or just simply dry threads on the cups. Is it a cracking noise? is there play on the axle? does it spin smooth or is there a tight spot?

The tools to take these brackets out are very cheap and will do the trick (you can pay so much more if you wanted too but cheap/correct will do). Only use screw drivers and hammers if you never want to use this bracket again and are happy with skinned knuckles and missing/dented paint.

Undo the lock ring first then unscrew the adjustable cup with a pin spanner. Don't use an adjustable spanner on the fixed cup with 2 flats, get a proper fixed cup spanner with plenty of heave. Once the bracket is out, clean the cups and axle. If there are no pits then change the bearings and reassemble. Use 1/4 inch loose balls. The adjustable cup will unscrew with a normal thread but the fixed cup has an opposite thread so comes out in the opposite way to normal.

If there is a pit mark on the cup or axle then replace with a cartridge unit.

I had the same BB on my Pine Mountain. I knew it was knackered so beiing a tight wad i spent ages trying to get it out with various home made tools.

Gave up in the end, bought the tool and then got the bracket out in 2 minutes flat.

I don't think it's a commonly used BB now so I replaced it with a cartridge one.

Happy to lend you the tool.

Mark

You might find this useful: --> http://www.drystonepaul.com/maintenance ... y_1992.jpg

As Xerxes says. The right tools are best if you're going to use the BB again but if you're not the drive side and lockring can be removed without special tools. The following Park Tool from Winstanleys is very good and approx half the price of other stores and is perfect for the adjusting cup which can be problematical.

http://www.winstanleysbikes.co.uk/produ ... anner_Tool

Sealed BBs are much less hassle and I have them on most of my bikes, but I still quite like working on the old style BBs. They last well with regular servicing a couple of times a year - as long as the cup surfaces and bearings are not pitted.

Hi

Thanks for all the replies...so I'm torn as to whether to buy the tools and see if the cups/axle is pitted in which case I need to replace the BB anyway. Just ditch it all together and hope that it comes out freely (after Two tones previous concerns over removing BB's from zolatone frames!) and get a suitable cartridge one...

From what I can gather the bearings are in a race having looked at other ones for sale...I must admit I am really a fit and forget kinda BB man and ride in all weathers (mainly wet... you should have seen my ride today!)

Next question would be... what size/width based on the pics of the current one be needed and is it worth paying for a better quality one?

Cheers

Wook

I tried but failed to get the new bearings for my one so just went for a UN 55 for about £12.

Left you a PM as well about this.