Cleaning inside of brake parts?

[macnut xj]

Okay, I decided it's time to fix the sticking rear/front brake system on my XJ. The problem seems to be in the rear master/prop valve. I removed the rear caliper and tried to push the piston back in with c-clamp. Wouldn't budge! Spooge hole inside the master looked clean. I disconnected the line from the caliper and the piston pushed right back in. So I removed the master and prop valve and pulled them apart. I have yet to find anything wrong, but inside the master is some spots of brown varnish looking stuff. I blew thru all passages and washed everything out with brake parts cleaner, but it didn't touch this brown varnish. How do you get that stuff out of there? Do you just scrap it out as best as you can? And does anybody have a clue what might be the cause for the sticking brakes?
Thanks!

John
82 XJ1100J
"eXJunk"

[ratbyk]

Brown Crud

If you can get at this brown crud, hit it with about 400 wet sand paper. Just enough to wear it off. Do not remove any metal and try and polish things up.
Ken/Sooke

[Underdog]

I've had pretty good luck with a product called Gum Cutter made by Berkibile. Check the local auto parts stores. It seems to be stronger than regular carb cleaner. It will remove paint so be careful with it. Although it's made primarily for cleaning carbs and EGR valves, it did a good job on my brake cyls. An alternative to sandpaper is 3M scotch brite pads. I use the red ones. You can stuff them in places where the sandpaper won't work. I also used the cylindrical cleaning brushes they sell for cleaning oil pasages in engines. Haveing said all that, my rear still hung up after being completely rebuilt. I've played around with the pushrod length and bled some fluid through. So far it hasn't acted up again. Probably waiting until I repaint the rotor for the second time. Good luck with yours.

[randy]

John, if you clean everything out and the brake still binds, you need new lines (shameless plug). Stainless are best.

Randy

[deo]

John,
Let me echo Randy. I had the rear binding up on me after a full rebuild. The old rubber lines breakdown over time and lose their ability to stay firm while in use. I put a new stainless one on and it works like they are supposed to. Although I didn't get my stainless from Randy they still work well. (Only did one so far Randy so I may still order the rest.)

dave