"lifetime" mainspring

Submitted by ezaragoza on January 18, 2023 - 4:57pm

Looking to replace the mainspring for my 1977 Bulova 23J 11AOACB watch. The mainspring is marked "Bulova Sealed Lifetime power do not open",
ink stamped H1, so of course I opened it and the spring is broken.

My questions are - does anyone you have the whole assembly ? or should just the spring get replaced?

According to Ranfft and other sources, the mainspring is 1.10 x 11.0 x 0.11mm.

Whole assembly or spring please :)

Ed Zaragoza

Posted January 20, 2023 - 7:56am

Hi Ed. Your watch isn't but 46 years old. That's a short lifetime. I'd contact Bulova and tell them the mainspring didn't last a lifetime and you want another one. Couldn't hurt nothing and who knows, they may send you another one. A lifetime seems like it should be longer than 46 years. Here's a link to contact them:

Contact us (bulova.com)

Posted January 20, 2023 - 9:17pm

This part hasn't been made for decades so any that you find complete would need to be opened and cleaned and then have the barrel greased.  If you order a new mainspring you would still need to clean and then grease the barrel or the spring won't "slip" correctly.

Those Ranfft numbers don't look right. The Jules Borel DB is down at the moment but Emmywatch.com shows the dimensions as 1.10 x 0.115 x 320 for a 10mm barrel with a GR reference of GR2644X. If you search with that GR ref you should be able to source one. McCaw has one for $18. Otherwise you could source one of the donor movements that is listed on the Emmywatch link from above and pull the mainspring from that.

Posted January 20, 2023 - 11:40pm

I usually but movements on ebay and swap out the entire barrell.

Posted February 2, 2023 - 9:14pm

I contacted Ofrei, and they sent back the following recommendation for a replacement spring.

Dennison Width: 2, Dennison Strength: 9.75, Length in Inches: 12.5 Metric Width: 1.1 mm, Metric Strength: 0.12 mm.

replaced fine, was able to close the barrel no issue, and the watch is back to life :)

Thanks to all

Eddie Zaragoza