Author Topic: rebuilt front calipers - success - thanks Motobrickers  (Read 238 times)

Offline Eville Rich

  • Motobrick Curious
  • Posts: 25
rebuilt front calipers - success - thanks Motobrickers
« on: August 05, 2019, 08:18:45 PM »

This past weekend I finally finished my project to redo the front brakes on my '87 K75S. I took my time doing it.  The advice from the forum was super helpful.  A few items:
1) Loosening all the bolts, including the bolts that hold the caliper together while the caliper is mounted was key. 
2) I installed new EBC rotors along with EBC HH sintered pads.  Went together just fine.
3) The seal kit and slider pin kit worked quite well.  I'd never rebuilt calipers before and by being careful and taking time, all went well.
4)  Cleaned first with brake fluid then finished with brake cleaner. Let it all dry. Lubed the seal with brake fluid.
5) Put the caliper halves together and torqued to the suggested 50 NM in the instructions with the rebuild kit.  Had to finished the torque with the calipers back on the bike. One rubber o-ring per caliper on my bike (each kit had two o-rings).
6)  Took a long time bleeding with a vacuum bleeder plus some careful squeeze/turn/close/release bleeding to finish it.  The vacuum bleeder did OK up but it didn't really do it without the traditional slow bleeding method.  I'll be dealing with the master cylinder and brake lines in the future - I wanted to isolate on variables in case I ran into issues.

When I opened the caliper halves I found some remaining watery brown fluid.  Glad I did this rebuild.  Cleaned up fine but I suspect they'd not been rebuilt before (~30k on the odo) and who knows about the bleeding history.  What triggered my rebuild was rapid brake pulsing.  Rather than fight to solve it with 32 year old stock parts, I just replaced the pads and rotors.  It stops so much better and smoother than before. 

While getting parts and taking my time, I also redid the mounting bits for the instrument cluster and took a few trips to the hardware store to sort out fairing mounting hardware.  I also replaced what I think was an Aeroflow windscreen with a stock screen.  That is also a big improvement for me.  Nice smooth airflow on the helmet.  The Aeroflow seemed to create more buffeting for me, anyway.

I'm going to ride it a bit for a while.  Maybe take up the brake lines and master cylinder later in the fall. She's feeling pretty good with new tires this spring, new rear Progressive shock, and new fork oil.  Plenty else to sort through to keep me occupied.

I appreciate the help on the board.  Hopefully I can share some useful things going forward.

Eville Rich

  • WI, USA
  • 1987 K75S

Offline herseyb

  • ^ Proficient Motobricker
  • Posts: 209
Re: rebuilt front calipers - success - thanks Motobrickers
« Reply #1 on: August 11, 2019, 10:34:56 PM »
greetings from brooklyn, wi

 :useless
  • Brooklyn
  • '90 K75 - '93 K1100RS (and a tw200)

Offline volador

  • ^ Proficient Motobricker
  • Posts: 111
  • NEEDS MORE CHROME
  • NYC
  • 1991 K100RS 1993 K75S ABS
FIVE BOROUGHS SISYPHEAN SOCIETY "WHEN LIFE THROWS YOU A CURVE... LEAN INTO IT"

Offline TommyT

  • New Brick Owner
  • ^ Motobrick Curious
  • Posts: 63
Re: rebuilt front calipers - success - thanks Motobrickers
« Reply #3 on: August 12, 2019, 06:17:18 AM »
I also replaced what I think was an Aeroflow windscreen with a stock screen.  That is also a big improvement for me.  Nice smooth airflow on the helmet.  The Aeroflow seemed to create more buffeting for me, anyway.
Which of the windscreens are taller? How tall are you may I ask?  Have 90 k75s with a stock windscreen and I am 6'3". I find the stock  one throws the airflow  right  into my helmet. I have been think of changing windscreens and thought the Aeroflow would be an option.
  • Olive NY
  • 1990 K75s, 1990 K75RT

Offline RobP

  • ^ Proficient Motobricker
  • Posts: 157
Re: rebuilt front calipers - success - thanks Motobrickers
« Reply #4 on: August 12, 2019, 11:36:39 AM »
RE: windscreen - The stock windscreen on my K100RS put the blast of air right in my helmet and the wind shriek and buffeting were almost unbearable at highway speeds.  Even with earplugs the noise was deafening. I went with the tall Aeroflow and that has transformed high speed crusing into a pleasant experience.  I am 6'1"
  • Driftwood, TX
  • 1985 K100RS

Offline herseyb

  • ^ Proficient Motobricker
  • Posts: 209
  • Brooklyn
  • '90 K75 - '93 K1100RS (and a tw200)

Offline Eville Rich

  • Motobrick Curious
  • Posts: 25
Re: rebuilt front calipers - success - thanks Motobrickers
« Reply #6 on: August 13, 2019, 07:30:57 PM »
Quote
Not of any old brake rebuild, doofus.  Of his very own sexy K bike!

:freebizzaro   I'll get some pics once it's looking a little sexier.  It's not bad but I have a few things to tidy up after my swap from the low to high seat.  Plus need to re-attach the lower fairing.

Quote
Which of the windscreens are taller? How tall are you may I ask? 

I'm a hair over six feet.  My last ride I felt the air right on my faceshield, but it was smooth up to 75 mph or so.  I suppose it could be due to the specific wind conditions at the time.  The aeroflow (or whatever I have) just seemed to create more buffeting. It's a good bit taller than the stock windscreen.  It also seemed to shake a good bit, but I suppose that might be addressed with my tightening of the fairing.  I'm riding with a Schuberth C3 Pro helmet and I suspect that helmets could also be a factor in varying experiences.  But even with the faceshield up, the blast of air on my face was smooth.  Until a bug hit my cheek.  But it was nice for a hot evening ride.  More testing to come.

Eville Rich
'87 K75S
'15 WR250R
16 Super Tenere
  • WI, USA
  • 1987 K75S

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