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Stuck Dust Cap on Dura-Ace 7800

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Stuck Dust Cap on Dura-Ace 7800

Old 04-04-09, 07:29 PM
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PanicDog
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Stuck Dust Cap on Dura-Ace 7800

I'm full of questions tonight!

I've got a Dura-Ace 7800 crankset that I am trying to remove. I have the Park BBT9 tool, but the dust cap on the left arm won't budge. I feel like I will need a real wrench to get enough leverage to loosen it. I guess whoever installed it tightened it too much? Not sure how they would do that if they used the BBT9 though. In any case, does anyone have any tricks for getting a tight dust cap off?

Here is a picture in case there is any confusion as to what part I'm talking about.



Thanks!
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Old 04-04-09, 08:05 PM
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JiveTurkey
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Did you loosen the pinch bolts first?

http://www.parktool.com/repair/readh...?id=95#shimano
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Old 04-04-09, 09:06 PM
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I was using Zinn's book which said to loosen the dust cap first. I just removed the pinch bolts and the dust cap is still too tight to turn with the BB9.

Any ideas on what could cause it to get stuck like this and ways to loosen it?

This is the same bike with the rusty headset. http://www.bikeforums.net/showthread.php?t=527673

I bought the bike used. Does this look like neglect?
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Old 04-04-09, 09:53 PM
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Perhaps the person who installed it tightened the crap out of it, which you are not supposed to. Either that or no lube was used on the threads when it was installed.

My advise is to put a few drops of an oil like tri flow into the gap in the crank arm, aiming for the cap. I believe the cap on the DA cranks is alloy instead of plastic like the rest of them so some lube may help free the cap. If you have a rubber mallet try lightly tapping it a bit in hopes that the oil penetrates into the threads a bit.
Good luck.
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Old 04-04-09, 09:56 PM
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you can grab the TL-FC15 with some channel locks or something and it won't harm it too much. But don't put it back anywhere near so tight. It's supposed to be 1Nm which is practically nothing. What I do is tighten it fairly snug to make sure the axle is pull all the way through the BB. Then I loosen it completely. Bring it up to contact and give it about 1/4 more of a turn. Just a light grip on the tool, if you're squeezing it, you made it too tight.
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Old 04-04-09, 10:31 PM
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Thanks guys! I dripped some oil on the threads and then I removed the head of the BBT9 tool from the handle and then wrapped a thick bath towel around the head to get some more leverage and I was able to get if off that way. I'll definitely keep it loose when I put it back on!
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Old 04-05-09, 10:00 AM
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dvs cycles
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First of all it is NOT a dust cap. It is to preload the bearings of the BB.
Loosen the 2 pinch bolts that attach the crank arm and it will take the pressure off the part.
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Old 04-05-09, 10:20 AM
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Originally Posted by dvs cycles View Post
First of all it is NOT a dust cap. It is to preload the bearings of the BB.
Loosen the 2 pinch bolts that attach the crank arm and it will take the pressure off the part.
First of all, he already posted that the pinch bolts were loosened and its still too tight.

I went through the same loosening learning curve and wore out the plastic piece on the park tool.

I then got one of these:



Nashbar Integrated Bottom Bracket Cup Bit

It's a preload tool on one side and a bb tool on the other and its metal. Comes with a socket drive adapter so you can install your big ole breaker bar if the "thing" is too tight.
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Old 04-05-09, 04:43 PM
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the tool to tighten the preload is a round plastic knob, meant to prevent people from over doing the preload on the bearings
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Old 04-06-09, 06:16 AM
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Originally Posted by merlin55 View Post
the tool to tighten the preload is a round plastic knob, meant to prevent people from over doing the preload on the bearings
Point taken however the thread is not about how the preload should be performed (which will come in handy when he ever gets the preload off and is ready to install it again) ... it's about what to do if someone did it wrong and it can't be removed with the little round plastic knob.

The tool was suggested for UN sticking the preload (subject of current thread) and NOT the installation of the preload (subject of future thread).
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