green brake fluid

Charles S Otwell · April 05, 2009, 10:09:03 PM

OK here is what happened (on the Valk, but brake are brakes) My front brakes started acting up, by that I mean sometimes the brake lever would feel normal and sometimes it would be hard to pull. They finally locked up and wouldn't release so I let the pressure off at the bleeder valve, both calipers released so I assumed the master cylinder wasn't letting the fluid return. Here is where the subject green fluid comes in, when I got home I removed the master cylinder, when I removed the last screw the rubber diaphragm popped the cover off and was swelled to twice the size of the cap (not an exaggeration). The fluid is clean and clear except for the green tint. the hole in the bottom was clean. Has anyone run across a brake fluid that would swell the rubber diaphragm, that much? I intend to flush the system and replace anything else rubber, including the line if I need to. So far the brakes have not locked up again, but I have been easy on front since it happened. I know that brake fluid will swell some types of rubber, but not usually it's own diaphragm. The bike has 39,000 miles on it and the fluid is to clean to be original. Has anyone run into this before?? post is a little long sorry

rjb/AKA Bob Barram · April 05, 2009, 11:26:13 PM

Charles, never heard of green fluid before and I am wondering if the previously owner put in something other than the recommended (is it dot 4 for your Valk)DOT fluid. It should say on the stock cap. That is the only reason I could think of why the rubber swelled..

Charles S Otwell · April 06, 2009, 12:44:16 AM

There are tons of info on green brake fluid every thing from the green brake fluid (LHM) used for Citroens to green algae caused by moisture to corrosion from the copper or brass washers used for seals at the fittings, but nothing about swelling the rubber to twice it's size. Oh well I'll go thru the whole system anyway, but I like to know what causes a problem so I'll know how to avoid it..

hootmon · April 06, 2009, 02:58:36 AM

I'm with Bob on this one.. Probably dot 3 used instead of dot 4...
Yes, replace ALL rubber parts which would include a caliper re-build.

Curtis_Valk · April 06, 2009, 01:10:40 PM

Quote from: hootmon on April 06, 2009, 02:58:36 AM
I'm with Bob on this one.. Probably dot 3 used instead of dot 4...
Yes, replace ALL rubber parts which would include a caliper re-build.

The only difference between DOT 3 and DOT 4 specification is the boiling temperature. I'd almost bet it was something other than brake fluid or else the DOT 5 something (the racing stuff that is not compatible, it's either 5.0 or 5.1 ......it escapes my mind right now).

I'm with you on the rebuild Hoot. No sense taking chances with brakes. Besides, that should only take Charles about ten minutes once he gets tools and parts lined up and ready.

Curtis

hootmon · April 06, 2009, 03:13:42 PM

Quote from: Curtis_Valk on April 06, 2009, 01:10:40 PM
The only difference between DOT 3 and DOT 4 specification is the boiling temperature.
Curtis

I believe you can use Dot 4 in Dot 3 systems, but I do not believe you should use Dot3 in Dot4 systems..
I've heard of other people having seal issues when used the other way around.. I could be wrong, but this is the report I have received from others. I do understand the Dot 4 is for higher boiling point..

Charles S Otwell · April 06, 2009, 03:33:55 PM

Quote[once he gets tools and parts lined up and ready.
/quote]

Yeah, but that could take days

Magnum Magna · April 06, 2009, 11:32:54 PM

I wonder if it swelled the diaphragm it could have softened the hose also and when braking it collapsed the hose. The collapsed hose will stay collapsed intern locking the brakes.

Smoked U · April 07, 2009, 01:16:56 AM

Your system has been contaminated with a petroleum based product that is not compatible with the rubber seal products that are designed for use with a water based (alcohol) system.

Drain a little of the fluid off at the wheel cylinders. If it does not have the green tint, then the contaminate has not reached the seals in the calipers and you probably won't need to rebuild them if they are not leaking or not releasing the pads from hard contact with the rotor. Suction out the master cylinder fluid and then drain all of the fluid from the system and flush it thoroughly with new DOT 4 fluid.

Drain the master cylinder and rebuild it at a minimum because it is lost along with the seal at the cover.

Could the lines be swelled? Again, depends on how far the contaminate reached through the system. Once the rest of the system is drained and refilled, you can test the brake system to see how it performs. No seizing and no soft mushy feel at the brake lever, you dodged an expensive bullet.

If your pocket is deep enough of course, you could go ahead and change out every piece of rubber on the sytem.

Chad in Michigan · April 07, 2009, 07:00:22 AM

i don't remember what color the fluid was, but i did the same mistake on an old geo metro i used to have. i think i used tranny fluid to fill up the reservior on the brakes and within a few months, they were completely shot. i wouldn't hesitate to replace anything rubber. once it swells, all it takes is that one time you need to panic stop and then it's too late.

Charles S Otwell · April 07, 2009, 10:48:49 AM

If your ever stranded (I am talking emergency here) and need brake fluid to make it home, use water, it won't hurt the seals, it will work and is easily flushed.

L J VFR · April 07, 2009, 11:39:55 AM

Quote from: Charles S Otwell on April 07, 2009, 10:48:49 AM
If your ever stranded (I am talking emergency here) and need brake fluid to make it home, use water, it won't hurt the seals, it will work and is easily flushed.

Huh, learn something every day.... Thanks Charles..

Chad in Michigan · April 07, 2009, 01:31:04 PM

might not hurt the seals, but what about the piston in the mast cylendar and the caliper? i've changed many of rusted calipers on vehicles due to water contamination, and i don't think you can compress water like that either.. dunno, but i'd stay away from the h20 method and call AAA.

Chad in Michigan · April 07, 2009, 01:45:37 PM

http://www.babcox.com/editorial/bf/bf40142.htm

read about water in brake fluid here

Charles S Otwell · April 07, 2009, 06:07:48 PM

Quotemight not hurt the seals, but what about the piston in the mast cylinder and the caliper? I've changed many of rusted calipers on vehicles due to water contamination, and i don't think you can compress water like that either.. dunno, but i'd stay away from the h20 method and call AAA.

I did not suggest you convert from brake fluid to water just mentioned that water could be supplemented for brake fluid in an Emergency, yes by all means if you have an alternative use it. Everyone doesn't have AAA, and yes water will compress like that. Of course you would completely flush the system at the first chance, I would go as far as to say you would might want to disassemble everything to clean it, but if your on the side of a mountain and lose a caliper seal or bust a line you could clamp off the side that's leaking refill the master cylinder with water and get back to civilization or you could walk home or push your bike back. I realize that most motorcycle have a front and rear brake that are separate and that you can usually limp home on just the one. As a matter of fact this tidbit of info came from back when the brake fluid in cars were not separated front from back, so there was probably no reason to mention it in the first place, but I did!