Master Cylinder Plunger Binds Up

[Guest]

I rebuilt my front Master Cylinder on my 80 GS1000GL but I have had nothing but issues. After I installed the new plunger and spring etc. The plunger binds up. I cleaned the bore that it slides into very well. I even took a bronze cleaning tool and hooked it up to my drill to make sure the bore was clean. Still if I put the plunger in and press it down with my finger til it bottoms out it get stuck and I have to push it back up with a screwdriver. Any ideas? This is how I have it going in there. <a href="http://s1234.photobucket.com/user/gs1000emt/media/IMG_3597.jpg.html" target="_blank"><img src="http://i1234.photobucket.com/albums/ff401/gs1000emt/IMG_3597.jpg" border="0" alt=" photo IMG_3597.jpg"/></a>

[gs1000emt]

http://i1234.photobucket.com/albums/ff401/gs1000emt/IMG_3597.jpg

[Agemax]

silly question but are you fitting it dry, or lubricated with clean brake fluid?

[gs1000emt]

lubed with clean fluid. Is there anything else I can use to lube it? Although its supposed to slide nicely with just brake fluid so something is wrong. They are all genuine parts from boulevard.

[Agemax]

clean brake fluid is ALL you should use as lubrication.
you say you used a cleaning tool, what was it, a wire brush type thing?
has it left the bore with a matt finish?
try polishing the bore using a small polishing mop on a dremmel or similar tool

[Nessism]

Disagree with trying to polish the bore. If there are pits in the metal, get a new master cylinder.

I'd take a close look at the metal plunger piece to see if there are any burrs that could get hung up in the bore. I had to polish the plunger one time because it was out of round and binding. That was a K&L kit though (never again).

[Agemax]

Disagree with trying to polish the bore. If there are pits in the metal, get a new master cylinder.

I'd take a close look at the metal plunger piece to see if there are any burrs that could get hung up in the bore. I had to polish the plunger one time because it was out of round and binding. That was a K&L kit though (never again).

i dont mean polish it, as in mirror polish, just polish it smooth if the drill tool he has used has left a rough finish!

[gs1000emt]

I used a bronze wire brush inserted into my drill. But I only did that after the initial problem with it binding up. So if the Master is bad? Where can I purchase another? Do I have to buy aftermarket? Im on a pretty tight budget.

[gs1000emt]

The order of parts in my pic is correct right? http://i1234.photobucket.com/albums/...t/IMG_3597.jpg

[hikermikem]

The order of parts in my pic is correct right? http://i1234.photobucket.com/albums/...t/IMG_3597.jpg

pic link broken...

[eil]

I'm concerned that the bronze brush might have scratched the bore. Shine a light down in there and try to feel it with your pinky, if it doesn't look and feel perfectly smooth, it's no good.

I recall when reassembling my master cylinder with new parts that the piston was a little sticky at first, even with copious amounts of fluid coating everything. After it was installed and properly bled, however, there was never any sign of binding or stickiness.

[eil]

This is the correct order for the parts. Left is toward the banjo bolt, right is toward the lever. Substitute the plastic washer and wire clip on the far right for the new dust boot.

[Elielrosario]

I recall when reassembling my master cylinder with new parts that the piston was a little sticky at first, even with copious amounts of fluid coating everything. After it was installed and properly bled, however, there was never any sign of binding or stickiness.

Were you able to do something to correct this "stickiness"?

[gs1000emt]

Sorry dont know why the link wasnt working. But yes that is the order I have it. Any suggestions on replacement masters?

[gs1000emt]

http://i1234.photobucket.com/albums/...t/IMG_3597.jpg Here see if this works. Any ideas to get bore super clean. I was using carb cleaner. Was that a no no?