best way to remove bearings from eccentric bottom bracket?

For discussions about bikes and equipment.
tommydog
Posts: 285
Joined: 11 Feb 2017, 6:48pm

best way to remove bearings from eccentric bottom bracket?

Postby tommydog » 25 Dec 2020, 4:19pm

I have a pinch style Eccentric bottom bracket, like below. The problem is I want to remove the bearings, but this involved a lot of torque when using the Park tools spline tool. Consequently, when I do up the pinch bolts, this is unable to hold the Eccentric bottom bracket in place while I use the Park Tool spline tool. I don't want to over torque these bolts in the frame, so have resorted to removing the Eccentric bottom bracket from the frame and plan to mount it in a vice and use a large breaker bar. The problem is if I put the Eccentric bottom bracket in the vice, it will chew up the Aluminium and I don't want to damage this .

I could wrap the Eccentric bottom bracket in plastic, leather, or a cloth, but I have never been very successful doing this when in high torque applications. I normally end up distorting / marring the service. I even thought about clamping the park tool in the vice and then using a strap wrench on the bottom bracket, but I don't think that would work due to the torque involved. Previously I have used some cheap soft jaws, but I found these useless for high torque stuff. I wonder if something more expensive like this would be better:

Heuer Jaws/Protected Jaws
https://www.amazon.co.uk/Protected-Plan ... =8-11&th=1

The above are nearly £45, but if it does the job it would be a good investment for other things.

Alternatively I could heat the bottom bracket case and then dump it in a bucket of engine oil for a week and then try with a strap wrench. But I neve like heating Aluminium, and it still may not come easy.

Below are some pictures so people know what I am up against. My main focus is getting the bearings out without marring anything.

Image

Image

Image

Image

Image

julianm
Posts: 149
Joined: 6 Jun 2011, 8:13pm

Re: best way to remove bearings from eccentric bottom bracket?

Postby julianm » 25 Dec 2020, 4:50pm

How about heat in boiling water, use an oil filter chain wrench on the central section? Protect that surface with a wrap of beer can shim/sheet lead? You might get away with a good quality chain whip if there is enough wrap. Good luck anyway!
wrench1.jpg
wrench1.jpg (7.04 KiB) Viewed 458 times

Nigel
Posts: 283
Joined: 25 Feb 2007, 6:29pm

Re: best way to remove bearings from eccentric bottom bracket?

Postby Nigel » 25 Dec 2020, 4:58pm

If Julian's approach doesn't work, here's a couple more ideas:

a) make some jaw pieces to fit into the grooves on the shell, so you don't damage the outer faces (which fit to the frame). That's a milling machine, or careful filing, job on some suitable offcuts. Then use those shaped jaws in the vice to hold the shell.

b) if that shell is solid, apart from the cylindrical hole through middle for the BB, then could put two moderate size holes for pins into the body (in the groove areas, going for the mid-point of eccentricity for max material in both holes), such that the pins provide the turning resistance in the vice, rather than scuffing up the surface material. I'd be looking at 6 or 8mm for the pins. Possibly use a M6 or M8 bolt into a tapped hole as the pin, so easier to remove when all is done. Hole could be filled with a plastic plug if thought necessary when re-assembling into bike.

And, just checking, you are trying to turn the tool the "right" way. One side of an English standard BB has a left-hand thread.

User avatar
Chris Jeggo
Posts: 203
Joined: 3 Jul 2010, 9:44am
Location: Woking

Re: best way to remove bearings from eccentric bottom bracket?

Postby Chris Jeggo » 25 Dec 2020, 6:29pm

I have been trying to visualise what happens if you use two BB cup removal tools, with one in the vice and a spanner applied to the other. I think things start to come apart somewhere, but I might be missing something.

julianm
Posts: 149
Joined: 6 Jun 2011, 8:13pm

Re: best way to remove bearings from eccentric bottom bracket?

Postby julianm » 25 Dec 2020, 6:43pm

Couple more ideas - a Stillson wrench would probably be effective but would obviously dig into that central section - protect it with a slit length of pvc waste pipe?
U bolt/exhaust clamp on the centre & bolt a bar or ring spanner to it over the pvc.
Dismantle your car engine & borrow a connecting rod to clamp on the centre using the shells to protect the alloy.
When you put it back together use a good smear of this on it :
moly.jpg
moly.jpg (4.72 KiB) Viewed 411 times

which should make life easier the next time.
Good luck & Happy Christmas!

User avatar
531colin
Posts: 13413
Joined: 4 Dec 2009, 6:56pm
Location: North Yorkshire

Re: best way to remove bearings from eccentric bottom bracket?

Postby 531colin » 25 Dec 2020, 7:15pm

Chris Jeggo wrote:I have been trying to visualise what happens if you use two BB cup removal tools, with one in the vice and a spanner applied to the other. I think things start to come apart somewhere, but I might be missing something.


I like this idea. I think if you try to undo the left side (the loose cup on a unit BB, which is a normal thread) this will have the effect of tightening the BB unit in the ali shell. If the left cup comes out, I would make some "Vee" blocks out of wood and use them to clamp the ali. eccentric in the vice to undo the BB unit.

It looks clean enough, but if you suspect its either corroded in or fixed with threadseal then those things need different treatment. On this subject, you say the ali eccentric turns in the frame before the BB unit lets go....did you install the BB unit?

Those soft vice faces are silly money, SJSC will sell you a new ali. eccentric for less than that.

gregoryoftours
Posts: 1467
Joined: 22 May 2011, 7:14pm

Re: best way to remove bearings from eccentric bottom bracket?

Postby gregoryoftours » 25 Dec 2020, 7:43pm

Surely having a bb tool in each side and torquing against each other won't work because of the thread direction of BSA BB. Well I guess it would work to remove whichever side was looser but not the other side.

rjb
Posts: 4294
Joined: 11 Jan 2007, 10:25am
Location: Somerset (originally 60/70's Plymouth)

Re: best way to remove bearings from eccentric bottom bracket?

Postby rjb » 25 Dec 2020, 7:52pm

gregoryoftours wrote:Surely having a bb tool in each side and torquing against each other won't work because of the thread direction of BSA BB.


It should work because as you tighten one side the other unscrews. Grease the one that comes loose then reverse the spanner direction. I would not put the remover directly in the vice jaw, I split my cast iron vice removing a freewheel from a tandem wheel. Put the spanner in the vice jaws.

You could try reinstalling the bottom bracket eccentric the opposite way round to the left side is on the right. Precession could then work in you favour to loosen things up if you are not in a hurry. :wink:
At the last count:- Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin, Raleigh 20, Falcon K2 MTB dropped bar tourer, Longstaff trike conversion on a Falcon corsa. :D

PT1029
Posts: 973
Joined: 16 Apr 2012, 9:20pm

Re: best way to remove bearings from eccentric bottom bracket?

Postby PT1029 » 25 Dec 2020, 7:58pm

Suggest
1. Generous heat to dry out any moisture in the threads, any oxide - hydroscopic - in the threads will contract (having expanded when wet), thus making the threads less tight.
2. In the thinner central section, drill a hole right into the cavity, Using a decent penetrating oil (3 in 1 orange spray can, plus gas, others available, blue WD40 can not much good here) put penetrating oil into both ends of the cavity, leave/repeat for some days or weeks.

Then have another go at loosening cups as per various suggestions above.
The drilled hole can be quite easily blocked off before reassembly, but ensure the blocking is secure, as damp/salty road muck can get there via the clamping slots in the bike frame.

Grease or (better) copperslip the BB threads generously before reassembly, ditto eccentric in the bike frame.

PH
Posts: 9964
Joined: 21 Jan 2007, 12:31am
Location: Derby
Contact:

Re: best way to remove bearings from eccentric bottom bracket?

Postby PH » 25 Dec 2020, 8:14pm

Is there some way to utilise the pin spanner holes to stop the eccentric turning in the frame? Or even out of the frame? It's a big lump of aluminium, it wouldn't harm it to drill some extra holes. Or if you're putting it in a vice, work out a way of clamping the middle section, it won't matter if you mark it, it doesn't touch anything and no one will see it.
I've never had an issue with the three frames I've had using this style of EBB, two and four bolt designs, I've removed them in the frame. Though taking them out and re-greasing is part of my maintenance routine, whether EBB or not.

colin54
Posts: 1560
Joined: 24 Sep 2013, 4:34pm

Re: best way to remove bearings from eccentric bottom bracket?

Postby colin54 » 25 Dec 2020, 8:59pm

Is there enough room to get a piece of medium/coarse emery or sand paper between the eccentric and the frame BB shell if there is, and you then clamp it up there might be enough increase in friction to stop it turning .
There's a v pipe vice in that Record 75 vice by the way if you have the loose v block that goes with the fixed part, that might grab it if there's enough room, you can see one half of it in your last picture.

AndyA
Posts: 492
Joined: 21 Mar 2009, 9:16pm
Location: Edinburgh

Re: best way to remove bearings from eccentric bottom bracket?

Postby AndyA » 25 Dec 2020, 10:29pm

Get someone to machine you a set of tube blocks that are 0.2mm less than the OD of the eccentric and clamp them in the vice. Hardwood would work fine but aluminium is best. If the torque proves too much put a bit of emery between the blocks and eccentric for extra friction. I also think a decent strap wrench would work if everything is very clean

Brucey
Posts: 42940
Joined: 4 Jan 2012, 6:25pm

Re: best way to remove bearings from eccentric bottom bracket?

Postby Brucey » 25 Dec 2020, 11:24pm

If you

a) tighten the pinch bolts on a bone dry eccentric

AND

b) hold the other cup

at the same time then you can end up with far more torque on the cup you are trying to unscrew.

Heat will help.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

tommydog
Posts: 285
Joined: 11 Feb 2017, 6:48pm

Re: best way to remove bearings from eccentric bottom bracket?

Postby tommydog » 26 Dec 2020, 8:43am

Chris Jeggo wrote:I have been trying to visualise what happens if you use two BB cup removal tools, with one in the vice and a spanner applied to the other. I think things start to come apart somewhere, but I might be missing something.


You would get one side off this way, but it would still leave you with a problem of getting the other side off. Plus if you take one side off, you have effectively tightened the opposite side.

PH wrote:Is there some way to utilise the pin spanner holes to stop the eccentric turning in the frame?


The pin holes are only 5mm and not very deep. Plus once you have removed the one side, you then need a way to hold it to get the other side off.

rjb wrote: I would not put the remover directly in the vice jaw, I split my cast iron vice removing a freewheel from a tandem wheel.


Absolutely no worries here. The vice is an old British Record 75 (I believe around 1935). It's all cast steel and pretty much indestructible. It even has an anvil on the top for beating down on things. In the past, I have used the vice to bend 5mm metal plate and clamped plenty of stubborn things in there for use with a very long breaker bar. If you can pick up one of these vices, I recommend it. But I know what you mean about cheap vices, some look very nice from China, but they just crack with hardly any force.


colin54 wrote:Is there enough room to get a piece of medium/coarse emery or sand paper between the eccentric and the frame BB shell if there is, and you then clamp it up there might be enough increase in friction to stop it turning .


Possibly, but as it won't come easy I am reluctant to use brute force when it is in the frame. I don't want to distort the frame in any way. I think it's better to find a way to hold it in the vice.


AndyA wrote: I also think a decent strap wrench would work if everything is very clean

I think it would probably end up slipping at higher torque. But I may have a go at making one of these below for fun. Do you think there is any chance it would work
https://www.youtube.com/watch?v=zXWgLP3Bems

Brucey
Posts: 42940
Joined: 4 Jan 2012, 6:25pm

Re: best way to remove bearings from eccentric bottom bracket?

Postby Brucey » 26 Dec 2020, 8:54am

tommydog wrote:
You would get one side off this way, but it would still leave you with a problem of getting the other side off. Plus if you take one side off, you have effectively tightened the opposite side...


IME both sides are unlikely to be equally tight. If you mark the parts you will see which side is moving and act accordingly.

As per my post above, if you use two methods to hold the eccentric still simultaneously, it does not follow that you will tighten the BB cup on one side whilst releasing the other one, for the simple reason that the reaction torque is shared between two things not just one, so ought to be about half as much.

FWIW the frame has to withstand quite high loads in use, so the idea that it can't contribute usefully to BB removal is simply not correct. What it is unlikely to do is withstand all the removal torque by itself, but that is OK, because it doesn't need to; if it withstands half of it, that is usually more than adequate.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~