Repair of 90's Rapidfire shifters
04-08-24, 08:33 AM
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Repair of 90's Rapidfire shifters
Hello Everyone,
I am a long time volunteer at a local non-profit that repairs and gives away bikes. We receive quite a few 90's era ATB's with Shimano Rapidfire shifters that are gummed up and do not operate. I am looking for suggestions of what solution(s) to soak the shifters in (off the bike) that will dissolve the hardened beeswax -like old Shimano grease. So far I have been pretty successful soaking them for about 2 days in gasoline but I am not crazy about the residue left (or flammability). I have heard of using mineral spirits, acetone, brake fluid, etc... I would like to use something safe and if possible non harsh chemicals, I am open to any and all suggestions to solve this problem ! Thanks in advance.
I am a long time volunteer at a local non-profit that repairs and gives away bikes. We receive quite a few 90's era ATB's with Shimano Rapidfire shifters that are gummed up and do not operate. I am looking for suggestions of what solution(s) to soak the shifters in (off the bike) that will dissolve the hardened beeswax -like old Shimano grease. So far I have been pretty successful soaking them for about 2 days in gasoline but I am not crazy about the residue left (or flammability). I have heard of using mineral spirits, acetone, brake fluid, etc... I would like to use something safe and if possible non harsh chemicals, I am open to any and all suggestions to solve this problem ! Thanks in advance.
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04-08-24, 09:21 AM
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Hello Everyone,
I am a long time volunteer at a local non-profit that repairs and gives away bikes. We receive quite a few 90's era ATB's with Shimano Rapidfire shifters that are gummed up and do not operate. I am looking for suggestions of what solution(s) to soak the shifters in (off the bike) that will dissolve the hardened beeswax -like old Shimano grease. So far I have been pretty successful soaking them for about 2 days in gasoline but I am not crazy about the residue left (or flammability). I have heard of using mineral spirits, acetone, brake fluid, etc... I would like to use something safe and if possible non harsh chemicals, I am open to any and all suggestions to solve this problem ! Thanks in advance.
I am a long time volunteer at a local non-profit that repairs and gives away bikes. We receive quite a few 90's era ATB's with Shimano Rapidfire shifters that are gummed up and do not operate. I am looking for suggestions of what solution(s) to soak the shifters in (off the bike) that will dissolve the hardened beeswax -like old Shimano grease. So far I have been pretty successful soaking them for about 2 days in gasoline but I am not crazy about the residue left (or flammability). I have heard of using mineral spirits, acetone, brake fluid, etc... I would like to use something safe and if possible non harsh chemicals, I am open to any and all suggestions to solve this problem ! Thanks in advance.
Direct lubrication to the pin that the pawl is on and make sure it can move back and forth freely. Light oil will do to lubricate it.
Here's the
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Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
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Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
04-08-24, 09:36 AM
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rapidfires/
if above video isn't fixing the issue you can further dismantle the unit.there are 3 spring attachment devises that all need to line up on reassembly.when apart you can physically remove the pawl off the shaft & thoroughly clean the gunk off.you may get lucky by using a fast drying spray solvent like carb gumout with the precise nozzle but there may still be gunk within.my '94 stx shifters have needed 3 cleanings-the gunk is very stubborn at times.
04-08-24, 09:38 AM
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Soaking the whole shifter isn't the way to fix the problem. You need a more targeted approach. The problem is that the pawl that moves a gear forward tends to get sticky. Spraying lubricant into the shifter housing may fix the problem but if you take the cover off the shifter you should be able to see the pawl that is the problem.
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04-08-24, 01:26 PM
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Typically I start by removing any covers that can be removed, spray in some Clean-Streak, isopropyl alcohol, or other degreaser into the shifter, find the stuck pawls and move them back and forth till they start working properly, use an air gun to spray out the degreaser and bits of old grease, then relubricate with Tri-Flow or Dri-Slide. Gets most shifters working fine again.
There are a few models that might not be worth the time, either because the above method hasn't had a great success rate on them, like 7 speed Deore LX M560, and any of the early 90's models that have two tiny finger-like pawls right next to each other, or because they work so poorly even when they aren't gummed up, such as Acera X ST-M290 or Nexave ST-T300.
There are a few models that might not be worth the time, either because the above method hasn't had a great success rate on them, like 7 speed Deore LX M560, and any of the early 90's models that have two tiny finger-like pawls right next to each other, or because they work so poorly even when they aren't gummed up, such as Acera X ST-M290 or Nexave ST-T300.
04-08-24, 06:40 PM
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04-08-24, 09:32 PM
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Typically I start by removing any covers that can be removed, spray in some Clean-Streak, isopropyl alcohol, or other degreaser into the shifter, find the stuck pawls and move them back and forth till they start working properly, use an air gun to spray out the degreaser and bits of old grease, then relubricate with Tri-Flow or Dri-Slide. Gets most shifters working fine again.
There are a few models that might not be worth the time, either because the above method hasn't had a great success rate on them, like 7 speed Deore LX M560, and any of the early 90's models that have two tiny finger-like pawls right next to each other, or because they work so poorly even when they aren't gummed up, such as Acera X ST-M290 or Nexave ST-T300.
There are a few models that might not be worth the time, either because the above method hasn't had a great success rate on them, like 7 speed Deore LX M560, and any of the early 90's models that have two tiny finger-like pawls right next to each other, or because they work so poorly even when they aren't gummed up, such as Acera X ST-M290 or Nexave ST-T300.
I do much the same cleaning, sometimes working the pawls with a pick to help the dissolving of the gummy grease in the pivot. Where i differ is in the lube after free pawl movement. I like oils with a swipe of grease on top after working in the thin then thick oils. Andy
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04-09-24, 08:55 AM
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04-09-24, 09:15 AM
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Thanks for the tag.
My experience has been that WD-40 and Clean Streak are only temporary fixes. If you really want to get those types of shifters working again, here is the method I use for rather good success:https://www.bikeforums.net/bicycle-m...l#post23196306
My experience has been that WD-40 and Clean Streak are only temporary fixes. If you really want to get those types of shifters working again, here is the method I use for rather good success:https://www.bikeforums.net/bicycle-m...l#post23196306
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04-09-24, 11:01 AM
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All good advice above. One thing I’ll sometimes do before degreaser and lubricant is to flush the shifter with boiling water. This can work wonders for loosening up that hardened grease.
04-09-24, 11:19 AM
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Ditto all the above. Dental picks are a big help--my dentist gives me his old ones when I ask. And I'll add, definitely stay away from the gasoline!
And kudos for volunteering at the nonprofit. Keep up the great work. It's how I enjoy spending a good part of my time. Freeing up stuck shifters is a big part of the work, and the reason many of them get donated.
And kudos for volunteering at the nonprofit. Keep up the great work. It's how I enjoy spending a good part of my time. Freeing up stuck shifters is a big part of the work, and the reason many of them get donated.
04-10-24, 03:23 AM
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Our tried and true method is to remove the covers, saturate the mechanisms with PB Blaster, working the shifter and pawls for a few minutes. Finally follow up with a squirt or two of the 3-IN-One lightweight penetrating oil. Work the shifter again and magic. This stuff is gold for these shifters.
Available at Home Depot https://www.homedepot.com/p/3-IN-ONE...0015/300719551
Available at Home Depot https://www.homedepot.com/p/3-IN-ONE...0015/300719551
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04-10-24, 03:24 AM
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Hello Everyone,
I am a long time volunteer at a local non-profit that repairs and gives away bikes. We receive quite a few 90's era ATB's with Shimano Rapidfire shifters that are gummed up and do not operate. I am looking for suggestions of what solution(s) to soak the shifters in (off the bike) that will dissolve the hardened beeswax -like old Shimano grease. So far I have been pretty successful soaking them for about 2 days in gasoline but I am not crazy about the residue left (or flammability). I have heard of using mineral spirits, acetone, brake fluid, etc... I would like to use something safe and if possible non harsh chemicals, I am open to any and all suggestions to solve this problem ! Thanks in advance.
I am a long time volunteer at a local non-profit that repairs and gives away bikes. We receive quite a few 90's era ATB's with Shimano Rapidfire shifters that are gummed up and do not operate. I am looking for suggestions of what solution(s) to soak the shifters in (off the bike) that will dissolve the hardened beeswax -like old Shimano grease. So far I have been pretty successful soaking them for about 2 days in gasoline but I am not crazy about the residue left (or flammability). I have heard of using mineral spirits, acetone, brake fluid, etc... I would like to use something safe and if possible non harsh chemicals, I am open to any and all suggestions to solve this problem ! Thanks in advance.
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04-11-24, 06:18 AM
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Hello Everyone,
I am a long time volunteer at a local non-profit that repairs and gives away bikes. We receive quite a few 90's era ATB's with Shimano Rapidfire shifters that are gummed up and do not operate. I am looking for suggestions of what solution(s) to soak the shifters in (off the bike) that will dissolve the hardened beeswax -like old Shimano grease. So far I have been pretty successful soaking them for about 2 days in gasoline but I am not crazy about the residue left (or flammability). I have heard of using mineral spirits, acetone, brake fluid, etc... I would like to use something safe and if possible non harsh chemicals, I am open to any and all suggestions to solve this problem ! Thanks in advance.
I am a long time volunteer at a local non-profit that repairs and gives away bikes. We receive quite a few 90's era ATB's with Shimano Rapidfire shifters that are gummed up and do not operate. I am looking for suggestions of what solution(s) to soak the shifters in (off the bike) that will dissolve the hardened beeswax -like old Shimano grease. So far I have been pretty successful soaking them for about 2 days in gasoline but I am not crazy about the residue left (or flammability). I have heard of using mineral spirits, acetone, brake fluid, etc... I would like to use something safe and if possible non harsh chemicals, I am open to any and all suggestions to solve this problem ! Thanks in advance.
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