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MG MGA - Goo Monster from Planet X vs. Cpt Master Cylinder

The brakes in my MGA have been acting really strange lately and I suspected old hoses coming apart from the inside. So tonight I replaced them, and when it came to bleeding the system I noticed a sheet of something floating in the fluid resevoir. I got my tweezers and pulled it out in pieces. I really can't tell what it is but I'm sure it wasn't helping any.

It's black but also looks kind of clear. Very gooey and soft, breaks apart easily. I got the majority of it out and then bled the front brakes. The right brake fluid came out black-ish at first before cleaning up. Left came out clear from the start.

Now here's the other strange part. I had my wife pump the brakes while I looked inside the MC. There are two holes, one where the plunger moves around and another smaller one behind it (towards cockpit). When she pumped the brakes, more of that goo streamed up out of the smaller hole!

What the h*ll is this stuff??? Here are a few photos (sorry about the quality)...

http://www.lbcnuts.com/temp/goo1.jpg

http://www.lbcnuts.com/temp/goo2.jpg

http://www.lbcnuts.com/temp/goo3.jpg

http://www.lbcnuts.com/temp/goo4.jpg

In photo 1 the flash went off but you can see how it's kind of clear. Photo 4 shows how gooey and stretchy it is.
Steve Simmons

Steve,
Your car has COOTIES!!! Keep it the hell away from mine as I don't want my car to get the same thing your car has.

That said.....

When was the last time it was bleed. Is it Dot 3 fluid. I had a problem with corosion before rebuilding my system with Dot 5. I now have no problems. It will be interesting to see what others have to say.

How about a Holloween run?
JEFF BECKER

It does not look like a result of corrosion. It looks like rubber products that have broken down, probably from the inside surface of the hoses, or from seals.
Time for new hoses, seals, and fluid.

Mick
Mick Anderson

The hoses were definately done for. I was thinking that's what the goo was from, but how did it get all the way to the MC? The fluid is DOT3 as far as I know (I guessed so by the rust and lack of paint on the outer MC). The fluid hasn't been changed in 2 years or so.
Steve Simmons

Steve, it appears that the goo from he-- has worked it way through your system. When the brakes retract they force fluid back into the master cylinder and with it comes the goo. It'll take some time, but you should be able to bleed it out of the system. I'd guess that the good is indeed breakdown from the rubber lines. If it was coming from the cups and seals you'd have other problems.
Bill Young

Gallstones
D Sjostrom

That is what old brake fliud turns in to (dot 3 worse than dot 5). The fluid absorbs water it loves water. Brake fluid also softens all the rubber pieces in the system, this is why flushing the brake fluid every 2 years is reccomended. Flushing postpones the deterioration of the rubber and eliminates the water. I have been refering to that goo as shark sh*t since the 70's. Before I changed to using silicone fluid back in the 80's we always used Lockheed/Girling brake fluid in English cars because the regular American stuff made the rubber turn soft and gooey faster.
I would reccomend that all rubber components of the brake/clutch system be replaced,hoses, wheel cyl seals ,caliper seals,clutch slave and master cyl seals. These really quite cheap and easy to do yourself. Then use the purple silicone fluid.
While you are at it you can clean and repaint around the master cyl for the last time because silicone doesn't eat paint.
There seems to be those who dislike silicone fluid because it requires a little more care in bleeding. I feel the advantages including ,WONT EAT PAINT, far out weigh the disadvantages. Silicone doesn't soften rubber this is both an advantage (rubber lasts longer) and a disadvantage (rubber stays firmer and doesn't seal as well)
Do IT ALL even if you use dot 5 now is not the time to underepair.
have fun Randy
R J Brown

Steve ,I would echo Randy's comments about the merits of silicone fluid. I switched for the recent brake & clutch job in which I replaced all cylinders, hoses etc. including a resleeved master cylinder. None of the wheel cyliders appeared rebuildable due to corrosion from water-absorption of the Dot 3 fluid. I blew the lines out with compressed air, flushed with methyl hydrate to remove all old fluid and then hit them with air again. Bleeding is more time consuming for sure, but I found that by working at it slowly and letting the car sit for a day or two between attempts allowed the air to slowly be released. All is good now and I am counting on less corrosion-induced problems down the road.
Tom Heath

that is exactly the same sort of sludge that came from my m/c three years ago. the PO hadn't driven the car for several years and I doubt that he ever bleed or changed the fluid. I replaced all the brake pipes, rubber hoses, wheel cylinders and had Joe Curto sleeve the m/c... I have good pedal now. Also, I now use silicone fluid.. Mike
mike

Steve,

With this thread title and your background, can we expect the Goo Monster video soon?

Joe (busy heating the popcorn).
Joe Cook

Oh god no! LOL!
Steve Simmons

Steve, make it easy on yourself get a Gunnison pressure bleeder from your favorite vendor. If you go silicone it makes life easier. Gary
gary starr

I have an EZ-bleed kit that uses tire pressure to bleed the system. Problem is, it will only accept up to 12 PSI or so which means you have to let the air out of your tires to use it. I hate that thing!
Steve Simmons

Steve

Be brave like me. I have the same kit. Never knew it was pressure limited to 12psi. I have been putting 27psi through it! Works fine.

Steve
Steve Gyles

Steve,
I found the same stuff all around my master cylinder when I was taking apart my project. It was outside the on the shelf and was a medium gray color and was for the most part dried up by the time I got around to it. I guess it was intially inside the master and then was dumped out by some unknowing mechanic. What a mess to clean up. Putty knife and a bunch of MEK. Stunk pretty bad if I remember.
Ken

I used full pressure once. I watched in horror as my master cylinder expanded like a balloon! This was in an MGB, but still...
Steve Simmons

Steve, I made a vacuum bleeder from an old pump, a solenoid valve and an old mayonaise jar. Works great and no problems with over pressures. It will pull fluid through the system in just a few minutes from the master cylinder clear out the far offside wheel cylinder. The only downside is that some bleeder valves tend to leak around the threads when loosened, so I remove the bleeder and wrap a couple of turns of teflon tape on the threads before starting. Use clear vinyl tubing and you can see the air bubbles moving through the lines. A bit of surgical tubing makes a good adaptor for various size bleeders.
Bill Young

I bought a vacuum bleeder last time I was in the US (when I went driving with Steve actually). I thought it would be better than the Eezibleed. I tried it, and went back to the eezibleed. I too use this on full tyre pressure, never had any problems.

I can also testify to the superior properties of Si fluid after using it for 18 years. Even then, I have had to replace seals and hoses once in that time, mainly because the clutch MC seals would not hold pressure, so I thought if I do one, I do them all.....

dominic

I've always been told not to use teflon tape on hydraulic fittings because the tape cannot withstand the pressures applied by the system. Is this just an old wives tale?
Steve Simmons

Steve,
Hydraulic fittings depend on the seal of the pipe inside rather than the threads, with reference to brakes. For NPT or other taper thread fittings, it would work, but you have to apply it correctly. Too many people wrap the tape around and around and around the threads. The tape will squish over time and flexing, and a leak will occur. When in the Navy, we were told to wrap only 1 1/4 threads around. The tape is used mainly to lubricate and seal small imperfections. I have never needed more than this and don't think I have had any leaks.
Mike
mike parker

I was told by my parts supplier that using silicone brake fluid would ruin my brake light switch in less than six months. If I wanted to not be changing them all the time I should Dot 5 fuild. Is there any truth to this remark as I would prefer to use silicone.
gordon

Gordon three years with silicone "still ticking" or is that "running"? I'll never go back... Mike
mike

Gordon,
Some rubber is adversely affected by silicone. I understand that there is a DOT 5.1 fluid which is better than 5.0.
Check this site.
http://www.thebrakeman.com/fluid_tech
mike parker

DOT 5 fluid does not affect the brake light switch in any way. Some of the new ones go bad in short order because they have very poor internal electrical contacts.

I have been using DOT 5 fluid for decades. After restoring my MGA, and putting another 100,000 miles on it, I replaced the brake switch in 1997. I have no record of buying one during the restoration, so the original factory part may have lasted 40 years and 250,000 miles (with various fluids). The replacement switch is still going strong after 8 years and another 100,000 miles. I have a spare in stock, just in case, but it has been accumulation a lot of dust.

DOT 5.1 fluid is nothing like Dot 5, not even silicone, but is more like an uprated version of DOT 4 with glycol base. The DOT specifications do not make any mention of the make-up of the fluid, only the performance characteristics.

Gotta love DOT 5 fluid. It doesn't eat paint, and makes the rubber parts last damn near forever.

$.02
Barney Gaylord

Hi Folks. Like Barney and others, I have had excellent results with Silicone fluid, and have run it for about 20 years in my MGA. It does not absorb moisture, does not eat paint, and preserves rubber seals. While it sounds too good to be true, this stuff really is fabulous! It honestly eliminates or greatly reduces many rust/corrosion induced hydraulic problems, and makes the entire braking system last much longer. I have also never had a problem with silicone fluid destroying brake light switches. I personally think that silicone fluid is the ONLY way to go. Cheers! Glenn
Glenn

Barney,
I thought that silicone didn't affect any rubber either, but the site I posted states that it can happen. I am sure I don't know how, but it is worth noting.
mike parker

This thread was discussed between 13/09/2005 and 16/09/2005

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