R90/6 brake pad replacement

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redavide
Posts: 103
Joined: Tue Dec 04, 2007 12:33 pm

R90/6 brake pad replacement

Post by redavide »

I plan on replacing R90/6 front brake pads. My R90/6 has twin discs (exactly like R90S). Does anyone have any link, etc. to detailed instructions, etc. on how to do this? And perhaps on how to recondition calipers while I'm at it. Thanks in advance.

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schrader7032
Posts: 7682
Joined: Fri Oct 27, 2006 3:00 am
Location: San Antonio, TX

Re: R90/6 brake pad replacement

Post by schrader7032 »

Check out boxer2valve...he might have some good videos:

https://www.youtube.com/results?search_ ... oxer2valve
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

redavide
Posts: 103
Joined: Tue Dec 04, 2007 12:33 pm

Re: R90/6 brake pad replacement

Post by redavide »

Thanks!

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srankin
Posts: 271
Joined: Fri Jul 14, 2017 8:45 pm
Location: Spencerport, NY USA

Re: R90/6 brake pad replacement

Post by srankin »

Another great source of repair videos is Brook Reams.
https://brook.reams.me

Anton is another source.http://www.largiader.com

I hate to say it the ATE calipers on the R90/6 are a bit fussy to change pads on, there is some messing needs be done with an adjustment bolt to get the pads properly seated and so they work best.

The good news is, it is not impossible nor does it require any special tools. Once you do it, you won't have a problem again. St.
Owner of a 84, R80RT and 78, R100RS

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schrader7032
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Joined: Fri Oct 27, 2006 3:00 am
Location: San Antonio, TX

Re: R90/6 brake pad replacement

Post by schrader7032 »

I used to have issues with that adjustment bolt on my single caliper ATE. I read something someone posted and it has helped quite a bit. I've heard about using a sharpie to draw lines across the disk and squeeze the brake, spin the wheel, and make adjustments until the lines are scrubbed off. Never really worked for me. What I do know is find a way to put light pressure on the hand lever and then use the Allen wrench to turn the adjuster. You will feel the eccentric pin get tight when going one direction and then back the other direction. In the middle is where you want to be. So, I get the feel of the range from tight-to-tight, then find the happy median.

As far as bleeding, if you are going to do the squeeze the lever and crack the bleed nipple method, avoid pulling the lever all the way to the handlebar. You will be dragging the internal rubber seal across potentially rusty or rough spots. Secure a piece of wood to the grip which will limit the throw of the lever...that throw should be about your normal usage. Then pump away and flush old out and new in. Then after that, pull the lever back to the piece of wood or to where you now have firm pressure, and tie it up for the night. This opens the internal valving and lets any trapped air bubbles come up and into the reservoir.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

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75R60
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Joined: Mon Jul 25, 2016 11:24 pm
Location: Boston

Re: R90/6 brake pad replacement

Post by 75R60 »

Thanks for this. Both of my bikes front brakes are very spongy. I’ve adjusted them the way you described here finding the center of the concentric pen with light pressure on the handbrake. Still very spongy I think maybe this way of getting rid of the air might help
Dang
‘75 R60/6
‘75 R90/6

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srankin
Posts: 271
Joined: Fri Jul 14, 2017 8:45 pm
Location: Spencerport, NY USA

Re: R90/6 brake pad replacement

Post by srankin »

If you have positioned the pads in the calipers as the instructions show and the lever is still spongy then there is possibly two reasons for it.

One reason may be air in the lines, bleeding will remove it, I will bet Brook has a video on how to do that.

Second, depending upon the age and miles the environment the bike has been in, the front flexible brake lines may just be shot. The original lines in time were prone to flexing. One of the first improvements I have done is to ditch the stock lines and replace them with stainless units.

Oh as a final thought, don't forget to make sure your brake cable from the handlebar to the master cylinder is properly adjusted.

Hopefully this helps, Cheers, St.
Owner of a 84, R80RT and 78, R100RS

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