Gunk in MC

[Rasputin]

Ok. What the heck causes this and how do I get rid of it? I am replacing the brake lines and rebuilding the MC's so it aint so bad. It is an 81 MNS and I wish it was still fluid but it looks like fish eggs. Seems to me that someone said it was from mixing different types of brake fluid. Is this correct? Oh bye the way I have a supplier who says he has rebuild kits for an 81 MNS front and Rear MC's. I have ordered one and it should be in soon. If he is correct would any one else want one? Heres the pics of what I am looking at.

[CatatonicBug]

As I've never seen the results of mixing Dot3/4 with Dot5, I don't know for certain what it looks like when you do that. However, what you have looks nasty!! Hopefully you can clean it out. Be sure to be VERY thorough, and rebuild the calipers too.

If you have found a supplier for rebuild kits for the REAR MC of an '81 MNS, buy LOTS of them!! They would be VERY valuable! They are not made anymore. The rear MC of the LH was the ONLY one that was an 11/16" bore (stamped on the outside of the MC). I searched and searched to find one for mine, and ended up having to swap out my MC for one from an XJ (3/4" bore).

Be sure that your supplier is NOT just selling you the kit for an XS1100 "Special". Those are different.

[Rasputin]

Be sure that your supplier is NOT just selling you the kit for an XS1100 "Special". Those are different.


Yup, I know that and I have repeatedly asked if it was for an 81LH XS1100 and they say it is. I will have to check it out once I receive it to be sure. One just never knows where ya may find this stuff. Is supposed to be delivery date of the 27th of this month so we will soon know more.

[DGXSER]

I'd have to agree that this would appear to be the described result of mixing DOT 5 with DOT 3/4 fluid. Not done it or seen it either.

Otherwise, I think someone emptied a ton of those gel packs they put int electronics gear into your MCs.

[tarzan]

Looks like orange chicken to me.

[Larrym]

Weird Science

Grisly looking alright. A real candidate for the PO "hall of shame." I've got some of both kinds of brake fluid and I'll mix it together in a glass jar. Maybe it will turn out like what you've discovered.

Whether the PO used the wrong fluid to top off the MC or did a major fluid replacement/flush with that concoction you're making the right call to replace as many parts as you can.

Hopefully this was just an isolated incident of the PO just not reading the fine print and not his standard operating practices.

Crossing my fingers for you!

[Macamon]

While the jury is out, you should take things apart and hose it down with brake cleaner (don't use petrolium cleaners as they contaminate the brake fluid [even just residue]). See if there is any oxidation on the cylinder walls. If you find corrosion in your master, you may want to go pick up a small 3 pronged hone for your drill motor. (I'll have to do this to my project bike I picked up this weekend). If you have never used one. don't sit in one spot too long (very tempting if you have one spot with pitting) but move the hone from the bottom to the top of the cylinder like you're... well, you know Full even strokes with no pause at the ends.
You want to cut the cylinder hole as evenly as possible from end to end.
Hopefully this is all unnecissary information. Good luck!

OH YEAH!! Don't forget to protect your painted surfaces from the new brake fluid. My master and both my calipers have the paint peeling from them... Maybe I'll just polish 'em

[jmyers40]

I have a set of shop-vac detailing ends that I got for about $10 for detailing my car for inspections. It worked wonders when I reccently cleaned out my front MC. I'd gently scrape out the scaley stuff with a pick from my gun cleaning kit, then suck it out with the little ends.

It was something similar to these:
Mini Car detailing Kit
but I bought them stateside; Wal-Mart I think

Good Luck.

[oldyam80sg]

Looks like someone added something other than brake fluid to your master cylinder.

[Rasputin]

Just for giggles I filled it with Dot3 and stirred it a bit. It went back to a fluid state (in the M/C anyways). That should make it much easier to clean up.

[Larrym]

Steve McQueen Lives On

Gawd!! Didn't you ever see the movie "The Blob"?? The original one not the other one.

Very risky to give something from another planet what it wants.

[Larrym]

It came from Outer Space!

Then again maybe not..



I just added the two types: DOT #3 and DOT#5.
Looks weird as the DOT5 is a light purpley color and the DOT3 is clear.
I'm going to just let it sit undisturbed for a while.

Let's see if there's a Nuk-yu-ler reaction or something!

[Ivan]

DOT 3 brake fluid is a mix of caster oil and alcohol, and that crud is what it looks like after sitting for several years and the alcohol evaporates out. Basically its just caster oil that's solidified.

Dumping more brake fluid in it was the proper move to clean it up.

[CatatonicBug]

Just for giggles I filled it with Dot3 and stirred it a bit. It went back to a fluid state (in the M/C anyways). That should make it much easier to clean up.

Good to know! I will add that to my pile of mental sticky-notes!