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MG TD TF 1500 - Goo In New Master Cylinder

I don't know about the rest of you, but I got a lot done over the weekend. My TF now sports a set of rebuilt carbs, the clutch controls are hooked up and adjusted, and I have most of the new brake parts on.

I think this has come up before, but I want to be sure, so I am asking again. My new, old stock Lockheed master cylinder has some sort of goo in the bottom and around the filler lid, that is sticky. It's some sort of lube, but I don't know if I should leave it in, and just pour in the new fluid, or clean it out. I am sort of against cleaning it out, because I don't know where all the cleaner is going, and if I can get it all out.
Next. If I am changing to silicone brake fluid, what about the old Castrol LMA that is sitting in all the pipes? I have installed four new wheel cylinders on the front and two new ones on the back, and I don't want contaminated fluid getting to those and messing up my new parts.
What is the advice from the experts?
Cleve

Although I'm not an expert, I think the consensus on changing over to silicone, is to rebuild all the cylinders (new rubber) and master cylinder (new rubber), replace all the lines and clean out all the T joints.
Otherwise, stick with the regular old stuff...

(Don't have any idea what the "goo" is)
gordon lawson

Clive - It is necessary to get all of the old LMA fluid out of the system. In the case of the lines, since you have replaced all of the wheel cylinders, you can probably get away with flushing them out with some silicone fluid before hooking them up to the cylinders (rather expensive flushing media though). Cheers - Dave
David DuBois

Goo is exactly what you don't want in your master cylinder. Goo is the ancient derivation of the Hersperian word 'Go' and is counter productive to your requirements of the MC. You want some 'some sort of lube' which can also be loosely attributed to 'stob' which of course is the ancient derivation for 'Stop'.

With respect to the goo (and switching to Silicon), and since I'm assuming you are looking for something to do with your car while it is winter, disassemble the MC, clean it completely with brake cleaner, spray it with clear acrylic, and reassemble using silicon fluid. Remove the brake hoses and replace them, and then remove the brake lines and flush them with areosol shots of CRC brake cleaner followed by compressed air. If you take off all the tees you can polish them with lemon juice and salt and spay on clear acrylic to preserve the color and shine of the brass bits. You might have to file down the brass fittings on the brake lines to get them to be smaller than the minor thread diameter so they will reinsert in the fittings and make the flared end of the brake line join properly with the mating fitting. The cool thing about the clear acrylic is that it dries really fast, and the silicon will not eat it up like Dot 3 does with paint.

Make sure you don't using any lube with petroleum products while putting together your brake system (don't ask me how I know this, but I did do my brake system twice in a one week period).

warmly,
dave
Dave Braun

Goo, or gel'ed brake fluid is very common in cylinders and lines that have not been used for some time.
I hope you plan to re-sleeve your cylinders as they are much better than new alum. ones. As for silicone fluid, its not really a big issue unless you live a hot humid climate. The new Castrol CMA will last you many years and you will not have to go through the laborious effort of flushing the system.
Colin Stafford

Dave and others

I was about to say that you have WAY to much time on your hands if you polish your brass fittings, but alas, mine are shiny also.

Cleave

I would unhook the lines from the rear sylinders and drain out the old fluid. Regardless if you change to silicon, flushing the fluid is not a bad idea. Dave's flusing imformation will clean the pipes.

I recommend getting anything out of the master cylinder.

If you do not drive the TD routinly, I recommend the silicon. Moisture issues are the primary reason I use it, but I really like that if I get it on the backing plates, it does not eat the paint.

Have had silicon in for 25+ years and not a single problem with breaks or need to check everything after sitting all winter.
Bruce Cunha

Colin,
I don't think this is brake fluid. The Master Cylinder is brand new, but has been sitting on the shelf for years. It is a clear, golden "muck" that looks and feels like dried glue.
If it is not safe, then why did Lockheed build the cylinders with the stuff in the first place?
Cleve

Hi Cleve, --- I wonder if that stuff you found in the MC is maybe a version of the brake grease that Moss sells. You are supposed to use it on reassembly of the cylinders during a rebuild. Or could it be dot3 brake fluid that has congeeled after sitting on the shelf for many years? In any event I would certainly get rid of it.

When I bleed the brakes with silicon fluid, I put what I bleed out in a container and label it "contaminated" fluid. Then when I want to flush out a line I use that instead of new stuff. So far seems to work fine and it satisfies my Scottish ancesters.
Hoot Mon,

Bob
R. K. (Bob) Jeffers

Bob,
Maybe we are related! My mother is a McLeod. You know what they say, "deep pockets, and short arms".
Cleve

Cleve,

I bought a similar NOS MC from Tom Coasting in Earlswood. likewise it was gooey and wrapped in that stiff waxey paper.
Definitely strip down and clean out all the dried preservative.
I also found the main seal had been sitting over a hole in the bore and had taken a set, so I fitted a new seal kit.
Silicon, well - DaveB has said it all. If you go to silicon do not reuse any seals, they will swell in silicon if previously used on std fluid. If you stick with std fluid it will need changing every 2 years or so. The hygroscopic effect will cause corrosion problems. See latest issue of ttt No. 12 on the T register site, for a TF tale of brake corrosion on std fluid.
Here's a 'cat amongst the pigeons' idea - during years of spannering I have found a smear of red rubber grease on the pistons (behind the seal where brake fluid should not be) is a big aid to preventing corrosion.
Good Luck
Graham
TD/C 7822
G.D. Smith

Graham,
Thanks for the advice. I don't have any red grease, but I do have some clear that is made by Raybestos, I think. It says it can be used inside and out of all brake parts and is good for rubber, like cups and seals. I use it when putting the cups in the bores.
I smelled of this goo in the master cylinder last night, and for sure, it is not brake fluid. So I am guessing it is assembly lube.
Cleve
Cleve

My first guess would be that it is some sort of dried up grease to prevent rust. I would try to clean it out with rubbing alcohol.
Carl Floyd

This thread was discussed between 28/11/2005 and 29/11/2005

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