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Author Topic: Pulsing front brakes  (Read 39564 times)

Offline Laitch

  • Faster than a speeding pullet
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Re: Pulsing front brakes
« Reply #50 on: July 25, 2018, 10:16:16 AM »
Quote from: Filmcamera on July 25, 2018, 09:44:04 AM
One of the places I was looking at to potentially replace my calipers was beemerboneyard and they have this link
A horned dilemma for unbelievers in BMW part numbers—that's for certain. :giggles
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  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

Offline Filmcamera

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Re: Pulsing front brakes
« Reply #51 on: July 25, 2018, 10:22:22 AM »
Also this from real oem but it does not mention the K1200RS but does mention the R1100 etc
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  • San Jose, Costa Rica
  • 1991 K100RS 16v ABS1, 2022 Triumph Tiger 900 Rally Pro
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Offline Motorhobo

  • +25 years of K75
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Re: Pulsing front brakes
« Reply #52 on: July 25, 2018, 10:24:04 AM »
Did you try Drake at http://kbikeparts.com/?
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1994/1995 K75 ABS Frankenbike: original engine 136k miles, frame from Gary Weaver (RIP), 173k miles -- Current Odometer: 198k miles
1994 K75 since 2013, 82,000 mi (19k mine) w/California Sidecar Friendship II Sidecar & Black Lab 'Miss B' - RIP

Past: 1974 Honda 550/4 (first bike), 1994 K75 (sold), 1995 K75 ABS (parts bike), Sidecar Dog & Best Bud 'Bo' - RIP

Offline Filmcamera

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Re: Pulsing front brakes
« Reply #53 on: July 25, 2018, 10:28:02 AM »
I found a set from a 1994 R1100 RS with part numbers which do match and they were the same price so I am going to get those...
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  • San Jose, Costa Rica
  • 1991 K100RS 16v ABS1, 2022 Triumph Tiger 900 Rally Pro
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Offline The Mighty Gryphon

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Re: Pulsing front brakes
« Reply #54 on: July 25, 2018, 03:12:49 PM »
I didn't check your link, but did Beemer Boneyard actually have a used part in stock?! :mbird
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  • In my garage in Marilla, NY
  • '91K100RS White/Blue
Current:
'91 K100RS16V "Moby Brick Too"

Past:
'94 K75RT "Ilsa, She Wolf of the SS"
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline Filmcamera

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Re: Pulsing front brakes
« Reply #55 on: July 25, 2018, 03:37:59 PM »
Lol noooo of course they did not have it in stock!! It was just that it said for K100, K1100 and 1200 etc - anyway in the end I got a set from a R1100rS which is the same part number etc so is for sure the right part.  Now I just have to hope it fixes the problem... I will have them in a couple of weeks due to shipping etc here but will report back when I have news.  Fingers crossed!
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  • San Jose, Costa Rica
  • 1991 K100RS 16v ABS1, 2022 Triumph Tiger 900 Rally Pro
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Offline rbm

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Re: Pulsing front brakes
« Reply #56 on: July 25, 2018, 06:07:59 PM »
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  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/

Offline Martin

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Re: Pulsing front brakes
« Reply #57 on: July 25, 2018, 06:14:41 PM »
FC when you get it sorted you might want to check out your old calipers. If it can be sorted you could either sell them and recoup some of your investment or keep as spares.
Regards Martin.
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  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline Filmcamera

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Re: Pulsing front brakes
« Reply #58 on: August 05, 2018, 10:45:31 AM »
Sigh... I cannot seem to get a break (pun intended)


I got the calipers yesterday and set about dismantling them to give them a clean etc when my trusty 6mm allen broke off inside the head of one of the bilts.





It is hardened steel (though clearly not hard enough!)





I have no clue how to get it  out, I tried drilling into it and after five minutes had made a tiny dent but no more.  It doesn't just pop out when banged from behind and is in too tight for a magnet to work.


Any ideas?
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  • San Jose, Costa Rica
  • 1991 K100RS 16v ABS1, 2022 Triumph Tiger 900 Rally Pro
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Offline Laitch

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Re: Pulsing front brakes
« Reply #59 on: August 05, 2018, 03:05:48 PM »
Quote from: Filmcamera on August 05, 2018, 10:45:31 AM
Any ideas?
Neglected fasteners should always  be soaked with penetrant before any attempt to remove them is undertaken.

If there are no threads engaged with that screw then heat both sides of the hole with a hair dryer or heat gun. Apply penetrant. Wait 10 minutes then put a notch with a punch at the line in the attached photo, engage the notch with a drift and pound the screw in the direction of the arrow. When it moves, you should be able to knock it from the hole on the shaft side.


If the hole is threaded, you'll just keep hammering it circularly to rotate it out.

If you ever need to drill something out like you attempted, light oil should be applied liberally to the bit's tip while drilling to keep its cutting edges sharp. Smallest bit diameters start the project and are replaced incrementally with larger bits. With right-hand fasteners I use left-hand bits—even in this case—but use what you've got if it comes to that. I use the highest drill speed possible.
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  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

Offline riots100

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Re: Pulsing front brakes
« Reply #60 on: August 05, 2018, 04:00:24 PM »
I had something like that happen to me on another project as well.  I roughly did what Laitch describes.  I cut a notch with a dremel and then used a cold chisel to engage the bolt.  It took some doing and a couple of notch cuts, but I finally got it out with patience and finesse.
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  • Los Angeles, CA
  • 1992 K75, 2007 K1200GT, 1991 K100RS
----
BDJ

Offline rbm

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Re: Pulsing front brakes
« Reply #61 on: August 05, 2018, 04:11:04 PM »
Maybe I'm the dissenter but I'd leave well enough alone.  Just clean them as much as possible as they stand, put them on the bike and ride.
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  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/

Offline Grant

  • Motobrick Curious
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Re: Pulsing front brakes
« Reply #62 on: August 07, 2018, 01:09:28 PM »
Here is my experience. First I put new brake pads in, it got worse, I mean rally bad. Next I took the calipers apart to clean them and reassembled. (I checked the rotors with a dial indicator and found no noticeable run-out, so eliminated this as a cause). When I was bleeding the brakes with my vacuum bleeder I noticed some gummy dark brown chunks coming through the bleeder line with the brake fluid. I took the bike out for a test drive and the brakes were fine, no more pulsing and very smooth at any speed!

My theory is that there was a build up of gummy brake fluid / crud? in the channel inside the caliper. One piston was working and the other was plugged, causing unequal pressure on one side of the rotor when braking and resulting in the pulsing effect.

I am going to take the calipers apart again to see if I can clean the channels to verify my theory, (although I think all the crud is now cleared).   
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  • Abbotsford BC Canada
  • 1984 K100 0005895
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