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Want to replace centering adjustment screws on Dura Ace BR-7403 brakes

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Want to replace centering adjustment screws on Dura Ace BR-7403 brakes

Old 11-29-20, 12:53 PM
  #1  
johnlink
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Want to replace centering adjustment screws on Dura Ace BR-7403 brakes

The attached pdf files shows the centering adjustment screws on Dura Ace BR-7403 brakes as Phillips head, but mine are straight. The screws in both the front and rear brakes are tight and the screwdriver tends to slip out of the slot, damaging it. I'd like to replace the centering adjustment screws with Phillips head screws or, even better, with socket head cap screws. One of the attached pdf files says the screws are M4 x 11.7. Is there any reason why the screws at https://www.ebay.com/itm/Genuine-Shi...EAAOSwZ2tcLH41 wouldn't work as replacements?


Attached Files
File Type: pdf
BR-7403 Instructions.pdf (126.0 KB, 1 views)
File Type: pdf
BR-7403.pdf (109.7 KB, 3 views)
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Old 11-29-20, 01:01 PM
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might work. all you can do is try them.

if you have problems with "phillips head screws slipping" consider going to 1/4 hex bits with accurately shaped Phillips drivers. I like the Wera items available on ebay. you can get hex and Torx drivers as well.

A really good Phillips screwdriver, like a Snap On, is OK when new. The one you pull out of the bargain bin at ace hardware will destroy fasteners from the start.

The shimano screws in particular seem very soft. A good "bit" fits correctly and will not slip and round out the screw head.

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Last edited by mpetry912; 11-29-20 at 01:05 PM.
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Old 11-29-20, 01:06 PM
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A genuine JIS screwdriver fits much better-
https://www.parktool.com/product/der...ewdriver-dsd-2
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Old 11-29-20, 01:08 PM
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Shimano screws are likely JIS drive, not Phillips. JIS drivers will probably fit the recesses properly. Having said that I prefer socket drive over Phillips. M4 x 12 should fit OK, if not it would be easy to grind off the slight extra length.
https://en.wikipedia.org/wiki/List_o...rives#Phillips
https://en.wikipedia.org/wiki/List_o...ves#JIS_B_1012
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Old 11-29-20, 01:14 PM
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Originally Posted by johnlink View Post
. I'd like to replace the centering adjustment screws with Phillips head screws or, even better, with socket head cap screws. One of the attached pdf files says the screws are M4 x 11.7.

I personally would just run down to my Ace or Tru Value hardware store with one of them and match it up with a SS socket head they have for like $1
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Old 11-29-20, 01:34 PM
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Try using a 2.5 or 3mm hex wrench in the existing bolts on your brake adjuster bolts.
Some of the dura ace brakes used a combination JIS and hex bolt. Assuming the bolt
is not seized in place, it should turn with a hex wrench.
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Old 11-29-20, 01:39 PM
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I think these will work, although I'd rather have a socket head as long as the screw was stainless steel. I just bought the 2-pack which cost me $1.25.
https://www.homedepot.com/p/M4-0-7-x...1058/204225839

Last edited by johnlink; 11-29-20 at 01:54 PM.
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Old 11-29-20, 01:40 PM
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Originally Posted by onsay99 View Post
Try using a 2.5 or 3mm hex wrench in the existing bolts on your brake adjuster bolts.
Some of the dura ace brakes used a combination JIS and hex bolt. Assuming the bolt
is not seized in place, it should turn with a hex wrench.
Neither the front nor the rear bolt is seized but no hex driver works.
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Old 11-29-20, 03:25 PM
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On the vast majority of the dual pivot calipers I see I don't touch these "centering" screws at all, unless the caliper is already set up really off center. Then I generally just set the screw so that the two sides/arms/pads are symmetrical. To center the caliper/pads I just turn the caliper backing plate (and the mounting bolt) on the frame. Andy
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Old 11-29-20, 03:50 PM
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Originally Posted by Andrew R Stewart View Post
On the vast majority of the dual pivot calipers I see I don't touch these "centering" screws at all, unless the caliper is already set up really off center. Then I generally just set the screw so that the two sides/arms/pads are symmetrical. To center the caliper/pads I just turn the caliper backing plate (and the mounting bolt) on the frame. Andy
That's the same thing I've always done, both with my 7403 brakes and previously with my 7402 brakes, but now that I have centering screws on the 7403 brakes I'd like to be able to use them.
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Old 11-30-20, 03:13 AM
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Originally Posted by johnlink View Post
I think these will work, although I'd rather have a socket head as long as the screw was stainless steel. I just bought the 2-pack which cost me $1.25.
https://www.homedepot.com/p/M4-0-7-x...1058/204225839
How about a hex head version
Hex Head cap Screws Metric

Or this Metric set screw with internal hex
Set Screw Metric M4
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Old 11-30-20, 10:03 AM
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Originally Posted by Andrew R Stewart View Post
On the vast majority of the dual pivot calipers I see I don't touch these "centering" screws at all, unless the caliper is already set up really off center. Then I generally just set the screw so that the two sides/arms/pads are symmetrical. To center the caliper/pads I just turn the caliper backing plate (and the mounting bolt) on the frame. Andy
+1. I have various Shimano dual pivot brakes, including Dura Ace BR-7700, on three bikes and have NEVER touched the centering screws. I center the brakes after removal or pad changes as Andy describes, just pivot them around the mounting bolt and hold them in position by hand while tightening the bolt. Dual pivots don't require the tricky centering procedure that old single pivots did.
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