Disposable brake master cylinders?

[RobThomas]

I bought a new M-cyl from Ebay for £32, including postage and tax. Not exactly expensive. It is going to replace this one which has done perhaps 1000 miles in the last 5 years. It has just had a wash to get the goop off for the photo.

Frankly, I'd rather pay more for one that lasted longer. Market forces???

mastergrotty.jpg (137.16 KiB) Viewed 2417 times

[les]

Sometimes when reading posts I am not sure I'm understanding the issue, in this case you say you bought a m/c for £32, and then go on to say, you'd rather pay more for one that lasted longer. I'm left wondering why you didn't?
Forgive me if I'm missing something.

[RobThomas]

Ahhh...That one is a genuine Lockheed M-cyl that hasn't lasted and has now been replaced with the cheapo replica since they don't seem to last long enough to justify the expense of another Lockheed one, hence the suggestion that they are bocoming a 'disposable item'.

I can't recall ever having to replace the M-cyl in a modern car. 200,000 in a Ford Mondeo and the master was just like new so I stuck it in a drawer in the garage. Maybe the creeping rust from the outside of the body has started to climb up into the bore? Modern masters seem to be either a corrosion-resistant alloy or well plated steel whereas the Morris ones are almost designed to rust upon fitting.

Maybe the answer is to go the Mazda 323 route or get the Lockheed one zinc plated???

[Sleeper]

Get the lockheed one re-sleeved in stainless..

Past Parts i Bury St Edmunds

John

[RobThomas]

£135 sounds a sensible price. I wonder if there is a market for ones converted from new???

[RobThomas]

I've found a Tilton Master cylinder with remote filler and will look into it.

Meanwhile, I'm searching for the git who repalced all the gearbox tunnel cover hardware with metric self tapping screws when the new floor was welded in 5 years ago.

[les]

Never thought of self tappers as being metric or indeed imperial! I thought they had their own thread pattern.
If the threads in the floor are damaged you might recover them with a suitable tap, 1/4 bsf ?

[RobThomas]

Yes, thanks. All rethreaded and ready to go with some spare brassware. The heads on these self tappers were metric hexagon, nasty modern things with coarse threads that barely held anything in place so they didn't need much work to tidy up. Lots of goop around the cover that had turned to sticky Treacle and had soaked into the carpet. Ughhh! Glad I had my interview last week since it'll take ages to clean my fingernails (Got the job, by the way)

[David W.]

Back to the master cylinder....
Goop on the outside shouldn't effect the function. Exactly why and how did the mc fail? You said 1000 miles in 5 years, so it didn't get much exercise. Are you using good brake fluid that won't degrade?
I think you need to find the source of the goop on the outside, and fix that problem.

[RobThomas]

The previous owner had lots of work done 5 years ago, including new floors and brakes. That Lockheed M-cyl had sat in the chassis leg with dust, lots of brake fluid and probably some waxoyl. It seems to have stayed wet down the sides of the body, presumably from dust and brake fluid combining to make a great corrosion source. The rust on the outside had also crept into the bore at the front, the dust cover having not sealed anything out of there. I'd guess the process was created by overfilling that spilled down the chassis leg and then slow leaking that drew moisture into the workings of the cylinder. The drain hole beneath the cylinder was also very clogged up with stone-chip from the underside.

This time I have applied some storage wax to the cast cylinder, stuff that fell off of the back of the RAF stores. The chassis leg got cleaned out, the various holes either unblocked or covered over with quality tape and then Dinitrol wax sprayed in. Not sure what else can be done???

[biomed32uk]

Sounds very similar to what I have been doing, fortunately the master cylinder was OK and not in trouble, took the opportunity to clean it out, and fit some new seals.

The main reason for doing it was to sort the cage nuts underneath it, or the lack of them. Having to take the master cylinder out should I want to drop the gearbox cross bracket off would be a right royal pain, a job that's been on the to do list for a while.

Also been there with the bodge fairy with a mixture of all sorts of self tappers holding the gearbox cover down, all reclaimed with a 1/4 BSF tap. New set of screws and some closed cell neoprene tape sorted that a couple of years ago, cover came out a treat this time with no sticky goo around.

[ianmack]

If a little used good quality cylinder fails early it has usually got damp inside. When I fit a new cylinder I smear red brake grease under the rubber end cover, for both lubrication and damp prevention.

[amgrave]

I agree with the red rubber grease, I’ve used it on my master and slave cylinders. It was also one of the things Roy used to suggest.

[DAVIDMCCULLOUGH]

I had a new master cylinder fail after about 2 years. I found some old stock lockheed seals and fitted them into it, probably about 7-8 years ago now and no problems since.

[alanworland]

I re sealed all my cylinders and assembled with red grease (original master cylinder) and used silicone fluid which has been fine for the last 10 years.

Alan

[amgrave]

+1 for silicone fluid, been in for three years so far and no problems, don't even have to change it every two years either