Vintage Campagnolo clamp on DT shifter issue
#1
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Vintage Campagnolo clamp on DT shifter issue
I recently came across and acquired a vintage Campagnolo clamp on DT shifter assembly found in a parts box at a "flea market-like" event. It was by no means NOS but the aluminum levers were in nice condition. The steel parts had some rust but I figured that a bath in EvapOrust would remedy much of that. I should note that neither of the levers would move but again hoped that the time in the EvapOrust would help fix that issue. Before going into the EvapOrust, I did as much disassembly as possible which amounted to removing the bolts securing the levers to the clamp on body, the Campagnolo logo'd outer keyed disk and a thin, keyed washer. I could not remove the levers from the bosses as they seemed to be "fused" together. Perhaps this is why the shifter was in the parts box. Anyway, I was hopeful that the EvapOrust would do its thing and clear some corrosion from the bosses allowing the levers to be removed. No such luck ! The rust on the steel parts of the clamp on assembly was mostly removed but I'm guessing another bimetallic fusion process was holding the aluminum levers to the steel bosses. I tried several penetrants to no avail. The final solution was to apply some (actually a lot ) of heat with a hot air paint stripper to the base of the levers while prying the levers off of the bosses. To be sure, there was a fair amount of corrosion on the underside of the levers and rust on the mating surfaces of the bosses. Steel parts went back into the EvapOrust and the corrosion on the aluminum levers cleaned up nicely with steel wool. Now comes the issue. I'm not completely sure that this lever assembly had all of the OEM parts and can't be sure that the previous owner had it assembled properly. I've Googled it and found numerous photos of numerous lever assemblies and see that most have washers on both the inside and outside of the levers and many have a "nylon" washer too. I'm attaching a photo below of how things came apart i.e. where the single thin washer was in the assembly.
From the internet photos, it seems like there should be a washer between the boss and the inside of the lever. Also, since the outside of the lever is slightly concave and the inside of the Campagnolo logo'd outer disk is slightly convex, a washer between those two surfaces might interfere with the "friction" action. I do suppose though that washer actually provides the "friction" action.
So, I guess my question is, do I have the proper assembly shown in the photo? If it is, do I need a washer between the inside of the lever and the mating surface of the boss? Thanks
From the internet photos, it seems like there should be a washer between the boss and the inside of the lever. Also, since the outside of the lever is slightly concave and the inside of the Campagnolo logo'd outer disk is slightly convex, a washer between those two surfaces might interfere with the "friction" action. I do suppose though that washer actually provides the "friction" action.
So, I guess my question is, do I have the proper assembly shown in the photo? If it is, do I need a washer between the inside of the lever and the mating surface of the boss? Thanks
#2
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That looks like it cleaned up real nice, eventually! I do suspect you might be missing some washers. The classic and vintage folks would know for sure, you should move this there.
#3
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Yes, it did clean up nicely! If I am missing a washer, it would have to be VERY thin since the outer Campagnolo logo'd disk would not fit into the concave recess of the lever. I did consider posting in the C & V section but thought this was more of a "mechanical" issue and assumed that a moderator would move it if that was an appropriate thing to do. I'm sure that plenty of bike mechanics have C & V interests but will concede that many if not most C & V enthusiasts are actually very mechanically inclined. I'm hoping for a definitive answer from either group .
#4
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So what I’ve done is lightly grease the inner mating surfaces between the bosses and levers, lightly grease the thin keyed washer, the outer convex logo’d disk and threads on the fixing bolt then reassembled in the order shown in the photo. With only a small amount of torque on the fixing bolt, there seems to be sufficient friction to allow lever movement and perhaps prevent unwanted movement RE: derailleur spring return tension. That would have to wait until I actually install the levers on a bike and run cables to the derailleurs. If I assume that the shifters had never been disassembled , it’s the way it should be. If they had been disassembled, I’ll have to rely on the knowledge and experience of the “experts” here on the forum .
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Is the other lever with similar parts, i.e. no more or fewer than those you've shown disassembled?
The Record shift levers went through several iterations. It does appear that you are missing the plastic friction plate with the convex surface to fit into the lever. The tension bolt may not be original, as it does not have the D-loop.
These are a later version than yours, and have a split washer under the tension bolt:
The Record shift levers went through several iterations. It does appear that you are missing the plastic friction plate with the convex surface to fit into the lever. The tension bolt may not be original, as it does not have the D-loop.
These are a later version than yours, and have a split washer under the tension bolt:
Last edited by JohnDThompson; 05-07-21 at 12:06 PM.
#6
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Thread Starter
Is the other lever with similar parts, i.e. no more or fewer than those you've shown disassembled?
The Record shift levers went through several iterations. It does appear that you are missing the plastic friction plate with the convex surface to fit into the lever. The tension bolt may not be original, as it does not have the D-loop.
These are a later version than yours, and have a split washer under the tension bolt:
The Record shift levers went through several iterations. It does appear that you are missing the plastic friction plate with the convex surface to fit into the lever. The tension bolt may not be original, as it does not have the D-loop.
These are a later version than yours, and have a split washer under the tension bolt:
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That set of levers is assembled correctly! It is a second generation Gran Sport set. The lever stops were pressed on the clamp and then the steel spacer is pressed on the lever boss holding the two plates in place. The bosses are held on the clamp by the spreading of the boss body like a rivet and the pieces then become one. Same process for both sides. The outer thin spring steel washer is what holds the tension on the shift lever because the convex chrome plated washer deforms the spring steel washer into the concave section of the lever. The tighter you make the screw into the boss , the more pressure is applied to the spring steel washer. HTH, smiles, MH
#8
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Thread Starter
That set of levers is assembled correctly! It is a second generation Gran Sport set. The lever stops were pressed on the clamp and then the steel spacer is pressed on the lever boss holding the two plates in place. The bosses are held on the clamp by the spreading of the boss body like a rivet and the pieces then become one. Same process for both sides. The outer thin spring steel washer is what holds the tension on the shift lever because the convex chrome plated washer deforms the spring steel washer into the concave section of the lever. The tighter you make the screw into the boss , the more pressure is applied to the spring steel washer. HTH, smiles, MH
Last edited by sovende; 05-07-21 at 05:42 PM.