[jwcfbd]

First off I'm ashamed to post this picture because I thought I took better care of my car but what would cause my brake fluid to have the consistency of pudding? I pulled the cap off the master cylinder the other day and saw this. I never had any problems with my brakes so I had no idea there was anything wrong.

[JACK_BURTON55]

i have no idea but that looks like the iron eating mold that grew in the creek behind our old house LOL yikes man, i better go check mine tommarow

[glhs#116]

Looks like lots of water got in, doesn't it?

As an aside, one of the things that really impressed me about this old GM iron was the brakes. Mine were neglected when I got it. Leak in the rear line, crud (like dirt and stuff) in the master cylinder. The fluid was cloudy (though thankfully not jelly like yours). All I did was replace the rear line and flush the system several times with new DOT4 until it ran clear. By flush I just mean open the bleeder on each corner and stomp the pedal a lot. No bad master cylinder, no bad brake pistons, no leaks. Just a solid pedal and great braking. I've been through about 1.5 sets of front pads since then it's all great. Not sure the newer stuff would take that kind of abuse!

Sam

P.S. Oh yeah, I've got a great one-man-bleed technique: Get yourself a long hose for the bleed screw and a catch jar. Plug the end of the hose with a screw. Slit the side of the hose for a few inches near the end with the screw. Now you have a one way valve for cheap. When you stomp, the fluid bursts out. When any suction occurs the slit just sucks closed. Nice!

P.P.S. I would take the same approach as a first step. First I would scoop all the crud you can out of the master cylinder reservoir. Then I would fill with nice fresh fluid. Then I would blow about five or six bottles of brake fluid through the system by visiting each corner in turn and flushing until you see good fluid. Then I would flush some more. Don't forget to keep topping up so you don't get air in. Good luck!

[glhs#116]

Here's another thought: That still looks like water to me. Is the lid of your master cylinder sealing? Is the rubber gone or something?

Sam

[bren566]

I have to agree with glhs. It definitely looks like water got in somehow.

[uneasyrider]

Ditto, water, common brake problem. If you haven't ever had a problem it might be that no one else has in the last 20yrs and that it's only been added to in that time. It finally got to a saturation point to where it looked as bad as it does now. Brake fluid has an affinity for water. Flush out the system and refill it and put a new seal on you master cyl. You should be able to get a new one at the local auto parts store. If they carry Motor Mite or Dorman I bet they have one on the shelf or can get it. You might just take it down and have it power bled and refilled. Don't let them sell you a brake job (unless of course they look bad) and see how it works. There is a big possability though that the water has pitted the bores on everything and it will start leaking now.

[Lemans71]

I've seen this happen a lot. The master cylinder cap is bad. Remember brake fluid is designed so that it absorbs water. Even water out of the air, so every time you let off the brake a little air (and moisture) gets into the master cylinder. The water will collect in the master cylinder and pool, like your did. Water will rust the inside of the master cylinder. Mix this combination up, (water, brake fluid, rust) and you have a mucky mix of gunk.
The whole system should be flushed out throughy. I would not be supprised if the master cylinder, wheel cylinders and/or calipers have to be replaced also. This gunk almost all the time finds its way down there after a period of time. Good luck P.

[Lemans71]

Master cylinder cap SEAL is bad.

[jwcfbd]

thanks guys. water is what I was thinking also but wasn't sure. I'm in the middle of a complete brake redo so I ran brake cleaner through the lines then blasted them out with compressed air. When I add fluid and bleed the brakes I'll make sure to run some extra fluid throught the lines.

[jwcfbd]

oh yeah and I checked the cap seal and it does look bad.

[Old Goat 67]

My 02 cents.
I always use silicone brake fluid and have never had any issues with it.
Anyone else care to comment?
Charles

[glhs#116]

The difference is the "DOT5" silicone stuff doesn't absorb water. Whether this is good or bad is something people have been known to disagree about. I think it all comes down to proper maintenance whichever fluid you run. The criticism I've heard of DOT5 is that since it doesn't absorb water it can trap water instead and cause localised rusting. The older fluid absorbs water and so it acts the same everywhere along the line.

So what, really. Both fluids will probably be a problem if left in for 20 or 30 years with no maintenance or a bad seal somewhere. Both will doubtless be problem free if changed somewhat regularly and sealed up. Of course the nice thing about DOT5 is it doesn't disolve paint. If I had DOT5 in my car I probably wouldn't have bare metal on my left front frame rail where a leak disolved ALL the primer and rustproofing off.

Sam

[sts]

Scrape out the gook; then service it? A reman m/c costs pennies. I'm one of the cheaper folks around, but I wouldn't reuse that cylinder if someone paid me.

[6D6GOAT]

i would spend a couple extra bucks and get a new MC not a rebuilt one.. the few rebuilt MC's i have tried (and wheel cylinders) have always leaked.

PS, i thought you couldnt use the silicone brake fluid if you already have some dot4 brake fluid in there. that you had to have a new dry brake system if you want to start using the dot5 brake fluid...??

[screamingchief]

i would spend a couple extra bucks and get a new MC not a rebuilt one.. the few rebuilt MC's i have tried (and wheel cylinders) have always leaked.

PS, i thought you couldnt use the silicone brake fluid if you already have some dot4 brake fluid in there. that you had to have a new dry brake system if you want to start using the dot5 brake fluid...??

Agree,100% Vic.

Dot 5 does'nt mix with any glycol based brake fluids.

I use castrol LMA (Low Moisture Absorbtion) DOT4 exclusively in all my brake jobs,and I dont worry about the paint,I just dont go around dousing the car with the stuff and I dont allow any leaks in the system,and I know how to bleed the brakes without getting fluid all over the place too.

If you ever do get DOT3 or DOT4 brake fluid on a painted surface,dont panic,just douse the area immediately with lots of fresh clean water,DO NOT attempt to rub it off in any way,that is what ruins the paint 9 out of 10 times...

The water will neutralize the brake fluids effect almost instantly.

[75TA]

Note that I was told that DOT 5 brake fluid requires special seals. So even if you start with a cleaned out system - you seals may not be suitable.