I'm thinking of dunking my rear mech in Jizer.

[KneesUp]

Please tell me I'm not the only one who has heard the stories about how well Coke cleans things, and has therefore assumed the title is a typo.

 

[fatboy123cycling]

Jizer is an excellent degreaser - it is water rinsable and also a corrosion inhibitor. It cleans Aluminium really well. With regard to your rear mech or cassette I would use the ultrasonics - however, I would agitate it regularly in the Jizer to flush any dirt out.
Drain and then lubricate. It will be o.k. with most plastics - and will be really good for chains - I would put it in the tank - but use a brush as well on the plates and between the links - drain and lubricate.

 

[slowmotion]

What's wrong with a brush and elbow grease. Works on MTB mech which get invisible through mud. Ultrasonic bath. Middle class crisis hey ?

No. I originally bought the bath to remove solder flux residues from small production batches of printed circuit boards. It subsequently proved handy for cleaning my chain and cassette when used with a different solvent, Jizer.

 

[slowmotion]

Jizer is an excellent degreaser - it is water rinsable and also a corrosion inhibitor. It cleans Aluminium really well. With regard to your rear mech or cassette I would use the ultrasonics - however, I would agitate it regularly in the Jizer to flush any dirt out.
Drain and then lubricate. It will be o.k. with most plastics - and will be really good for chains - I would put it in the tank - but use a brush as well on the plates and between the links - drain and lubricate.

After the Jizer, I wash the bike bits in the US bath with a fairly strong detergent solution and then repeated rinses with clean water. I then stick the bits in our oven in the kitchen for about 45 minutes at 70C before re-lubing.

 

[slowmotion]

Yes, go ahead and do it. An ultrasonic batch is great for all parts, including shifters - STIs, Ergos, the lot. All you will have to do afterwards is remove the idler wheels and dry the axles/bushings and lube them inside there. I have no idea what Jizer is but any soapy degreaser will do, no need to use a petroleum product - dangerous in an ultrasonic bath in anyway.

As for cleaning shifters in such a bath, Shimano products are fine but Campag Record ergo levers have a ball bearing inside that requires special attention once it's been in such a bath. I just disassemble it and rebuild from scratch, using the ultrasonic bath to clean the individual parts.

The ultrasonic bath works perfectly for chains as well, I use it primarily for that.

I took off the rear mech today, gave it a wipe, and looked at it in detail. All the pivots that the parallelogram action has for lateral (shifting) movement are pretty straightforward to re-lube after cleaning. However, the main swing pivot that tensions the chain (and has a fairly powerful torsion spring) might be a bit of a problem to get grease into. Campagnolo say that attempting to dismantle it could cause a problem. I got cold feet about lobbing it in the US bath. Am I being too cautious?

 

[Oldbloke]

Sounds like overkill to me, I soak the bits in paraffin then scrub off residue.

 

[Yellow Saddle]

I took off the rear mech today, gave it a wipe, and looked at it in detail. All the pivots that the parallelogram action has for lateral (shifting) movement are pretty straightforward to re-lube after cleaning. However, the main swing pivot that tensions the chain (and has a fairly powerful torsion spring) might be a bit of a problem to get grease into. Campagnolo say that attempting to dismantle it could cause a problem. I got cold feet about lobbing it in the US bath. Am I being too cautious?

Yes, you are.
If you feel you cannot get lube in there, buy yourself an aerosol can of White Lithium grease. It is great stuff. The grease is dissolved in a volatile carrier. It sprays like WD40 but the carrier evaporates and leaves behind a light grease, great for derailer springs, shifters or anywhere where you'd ideally like grease but can't get in to apply it.