Author Topic: Cleaning inside of old master cylinders  (Read 525 times)

0 Members and 1 Guest are viewing this topic.

Offline drifter

  • Full Member
  • Posts: 191
  • Country: 00
Cleaning inside of old master cylinders
« on: August 31, 2019, 01:17:43 AM »
Well I'm finally running out of things to fix on my franken Pan, should be done in a few days.  So I'm thinking of my next project, the 1978 Sportster Cafe Racer I bought 3 years ago.  Quick history: the previous owner bought it in 1990, put the engine in a drag frame and rode it a 1/4 mile at a time.  Then put it back in the original frame about 4 years ago, got it to run and passed away.  The bike has brand new tires with a date stamp of 1990.  I have to go through it and fix a few things, one of which is the disc brake system (front and back) dried up and left crud in the cylinders and hoses.  I would like to keep the originals so does anybody know how to clean them out and make them serviceable again?  Any whiz bang chemicals?  I pulled the rear master off and managed to remove the piston, it fought pretty hard. 

Offline PIRSCH FIRE WAGON

  • Site Supporter
  • Full Member
  • *****
  • Posts: 893
  • Country: us
Re: Cleaning inside of old master cylinders
« Reply #1 on: August 31, 2019, 06:26:33 AM »
Disassemble, Parts Cleaner, Brake Hone if need be, If the fluid container itself has to be cleaned of scale, use a Dremmel with a sand Drum. let air dry and reassemble with new, reinstall.
Tom

Offline JW113

  • Full Member
  • Posts: 1774
  • Country: 00
  • San Jose, California
Re: Cleaning inside of old master cylinders
« Reply #2 on: August 31, 2019, 08:43:07 AM »
Pine Sol and an ultrasonic cleaner.

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Offline HD Street Performance

  • Premium Vendor
  • Full Member
  • *****
  • Posts: 9127
  • Country: 00
    • HD Street Performance
Re: Cleaning inside of old master cylinders
« Reply #3 on: August 31, 2019, 09:30:43 AM »
No petroleum products should be used in a brake system to clean it.
Use denatured alcohol or fresh fluid. The cylinder itself can be honed with brake fluid for lubricant.

Offline JW113

  • Full Member
  • Posts: 1774
  • Country: 00
  • San Jose, California
Re: Cleaning inside of old master cylinders
« Reply #4 on: August 31, 2019, 12:30:00 PM »
You could try alcohol in an ultrasonic cleaner, would likely do well if it's only gunk you're trying to clear out. If it's corroded, need something with a little more bite than alcohol. I like Pine Sol, it's water based, is a degreaser, and acidic enough to eat corrosion.

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Offline drifter

  • Full Member
  • Posts: 191
  • Country: 00
Re: Cleaning inside of old master cylinders
« Reply #5 on: August 31, 2019, 10:54:27 PM »
Thanks guys. 
I forgot that I have a brake hone, too many tools (NEVER!) bought over the years and stored out of sight, thanks.
An excuse to buy another tool (see above), an ultrasonic cleaner sounds interesting if I can find a place to put it, thanks.

Whatever the residue is that is in there is hard and dry, I was hoping for a magic elixir but will see how your suggestions work first.

Offline HD Street Performance

  • Premium Vendor
  • Full Member
  • *****
  • Posts: 9127
  • Country: 00
    • HD Street Performance
Re: Cleaning inside of old master cylinders
« Reply #6 on: September 01, 2019, 07:09:42 AM »
Personally I would glass bead it then and then move forward with a flush and hone.

Offline BUGLET

  • Full Member
  • Posts: 565
Re: Cleaning inside of old master cylinders
« Reply #7 on: September 02, 2019, 10:58:37 AM »
   I would use plastic beads instead of glass and use a red scotch brite then a white one on a mandrill does a much better job then a hone.

Offline eglideic

  • Full Member
  • Posts: 1245
  • Country: us
Re: Cleaning inside of old master cylinders
« Reply #8 on: September 08, 2019, 07:03:10 AM »
 I'm puzzled. Why is it not recommended to use "Brake Parts Cleaner" ?????

Offline JW113

  • Full Member
  • Posts: 1774
  • Country: 00
  • San Jose, California
Re: Cleaning inside of old master cylinders
« Reply #9 on: September 08, 2019, 10:20:42 AM »
When brake cleaner used to contain 1,1,1 trichloroethane, it worked great, but those days are long gone. These days brake cleaner is simply acetone in a spray can. Total waste of money IMO.

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Offline eglideic

  • Full Member
  • Posts: 1245
  • Country: us
Re: Cleaning inside of old master cylinders
« Reply #10 on: September 09, 2019, 06:37:15 AM »
When brake cleaner used to contain 1,1,1 trichloroethane, it worked great, but those days are long gone. These days brake cleaner is simply acetone in a spray can. Total waste of money IMO.

-JW

 Thanks for the info. I guess being a chemistry professor like yourself does have its advantages.

Offline JW113

  • Full Member
  • Posts: 1774
  • Country: 00
  • San Jose, California
Re: Cleaning inside of old master cylinders
« Reply #11 on: September 10, 2019, 08:57:36 AM »
Or, perhaps I paid attention during chemistry class.

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber