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· 35mph Average
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Discussion Starter · #1 ·
Hi folks does anyone know if a dura ace rear brake will lose its power in the spring over time ? I got my new madone frame last week and i'm having problembs with the rear caliper not returning fully , i have checked all the new cables inners and outers and they seem to be free but there is some resistance on them when they enter and exit the top tube, i have taken the caliper to pieces and greased it and it seems to work perfectly fine by hand, but its about 4 years old , would a new caliper have more power in the spring ? anyone else had any problembs like this ? :confused:
 

· Banned forever.....or not
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The springs might wear out after 50 years.
 

· 35mph Average
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Discussion Starter · #6 ·
yes i've tried 4 new inners greased and 3 new outers without kinks and iv'e checked for ragged ends, to no avail, i'm completely at a loss and am even thinking of selling this new frame as my lbs have tried to fix it too .
 

· Matnlely Dregaend
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I had this problem... turned out the return spring on the STI lever was snapped.
 

· 35mph Average
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Discussion Starter · #10 ·
Hi folks are these return springs on the dura ace 9 speed shifter difficult to fit ? i don't think its this as the shifter seems to spring back ok, i'v just bought a new rear dura ace caliper , although i don't think the old one has anything wrong with it , i'm pretty sure the problem lies with the top tube entrance where the outer housing goes in, i stripped a little of the grey outer sleve of the outer cable and the resistance seemed to be less but still there,is there different thicknesses of outer cable ? that could cause the inner cable to become slightly squashed in the frame top tube entrance ?
 

· Number 2 on the course.
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joker said:
i'm pretty sure the problem lies with the top tube entrance where the outer housing goes in, i stripped a little of the grey outer sleve of the outer cable and the resistance seemed to be less but still there,is there different thicknesses of outer cable ? that could cause the inner cable to become slightly squashed in the frame top tube entrance ?
Brake cable housing is typically a plastic sleeve surrounded by a steel coil surrounded by a plastic casing.

When cutting a new length of cable housing it is possible to end up with the cut end of the coil deformed in such a way that it inhibits cable movement. Make sure that the housing ends are cut cleanly. Light work with a bench grinder or Dremel tool can clean up the cut ends -- just make sure that you don't overheat the plastic parts and melt them.

Resistance can also occur if the inner plastic sleeve is crushed, though this shouldn't be a significant cause of drag and ususally works itself out. You can take a sharpened spoke, small nail or similar and use it to ream out the end of the cut housing to further ensure free cable movement. The cable itself can also be used.

I am not familiar with your frame, so I can't comment on how it might be contributing to the problem. Obviously any place where there is resistance to cable travel needs to be appropriately addressed.
 

· 35mph Average
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Discussion Starter · #12 ·
thanks for the replys folks i've fixed the problem , my lbs and me never had the outer cable pushed in the frame housing far enough , resulting in severe drag on the inner cable,wich wouldn't allow my rear brake caliper to spring back normally.
 

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Don't lube or grease cables in plastic cable housings

Like the guy said, the inner sleeving of modern cable housing is usually (slippery) plastic, sometimes teflon-lined. You might want to spray the cable with silicone spray lube when you insert it into in the housing, but anything petroleum-based is likely to gum up, collect dirt, and cause the cable to bind after a while.
I prefer to use teflon-coated cables, especially for the rear brake, and change them once a year.
 

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Grease or lube

ti_litespeed said:
anything petroleum-based is likely to gum up, collect dirt, and cause the cable to bind after a while.
That's funny, because I have been greasing and oiling lined cable housing for decades with no problems whatsoever. I go about 10K miles between cleaning/lubing cables, and the cables last 30-40K miles. YMMV.
 
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