On Sunday, January 8, 2017 at 1:14:21 PM UTC-8, Benderthe.evilrobot wrote:
"Theodore Heise" wrote in message
...
On Sun, 08 Jan 2017 11:08:20 -0600,
AMuzi wrote:
On 1/7/2017 8:33 PM, Theodore Heise wrote:
Hi all,

I have an early 1990s Rodriguez tandem with a rear bottom
bracket in serious need of overhaul. The cranks flop
severely.

I've pulled the cranks and the lock ring on the left side, but
the adjustable cup won't come out. It turns about a quarter
turn, but then gets too stiff to turn further. It has no
flats for a wrench instead having holes for turning with a pin
spanner--so I'm unable to put a lot of force on it.

I've soaked it with WD40, but still no joy. Any advice for
me?

Delco 10.4020 penetrant is the best, PC Blaster is good.
Warming with a heat gun can help.

If no other path, flats can be cut on the cup with a disc
grinder to allow a wrench instead of those brittle expensive
pins.

p.s. Try the right side cup too. If that moves, you can easily
deal with the left one after disasssembly.

Thanks for the added tips. Off to get penetrating oil and new
pins now. Grinding on it is beyond my abilities, so if I'm not
able to get things off with the addition of penetrating oil and
time, I'll be hauling it off to my LBS.

At that stage; I'd turn it as far as the tight spot and give it a few
strikes with a hammer. sometimes you can ease it out bit at a time that way.

Once I had to shift a seized in pedal shaft, after snapping a couple of
spanners - I welded on the biggest nut I had a spanner for. Quenching the
hot steel with penetrating oil did slightly more than just spraying it on
cold. The same approach would probably work with a BB cup.

It is extremely bad practice to hammer a pin spanner. Firstly it will break the pins off on several types of pin spanners and in any case it will round off the holes so that you can't get one to work in any case. From the pen of Mr. Experience.