Brake master cylinder - original or aftermarket?

[unclealec]

Trying to pull a fast one here. I am still locked in a death struggle with the captive nuts and screws before I extract the master cylinder from its underground tomb.
Also, I am about to order some stuff from ESM.

So I ask - given that I have a disc brake conversion on my ex-PO Telephones van, with a remote reservoir, may I assume that it will be an original Lockeed cylinder? I shall order a rebuild kit if it is, but it would be nice to be able to rebuild it as soon as it is exhumed.

[philthehill]

Never assume anything.
It may or may not be an original Lockheed cylinder and it could be one of two internal diameters.
It may not be in a condition suitable for reconditioning.
I would wait until you have the thing in your hand, you have determined the size and the condition of the bore/cylinder.
When you have done all those things then order the requisite parts which may turn out to be be a new master cylinder.
Good luck
Phil

[geoberni]

I agree. Having recently found that my MC was leaking, I waited until I had removed it, to check the size marked on it and then, having looked at the condition of the bore, I decided to order a seal kit.

[unclealec]

Sounds like good advice. I wasn't aware of the two different piston diameters.

[ManyMinors]

The bore size changed back in about 1963. You're very unlikely to have the earlier type on your late van. However, as Phil says, it is impossible to know whether your van is still fitted with an original Lockheed cylinder or an aftermarket "pattern" one.
When I bought my Minor it had recently been fitted with a new aftermarket master cylinder and it failed quite quickly. I soon replaced it with a Lockheed one.

[unclealec]

I was wondering if it were possible to fit a remote reservoir to an aftermarket master cylinder.
My research suggested that it was not, so I asked the experts; apparently it is possible, so you may have saved me from myself. And possibly saved me some money if I have to buy a new replacement.

[oliver90owner]

……
When I bought my Minor it had recently been fitted with a new aftermarket master cylinder and it failed quite quickly. I soon replaced it with a Lockheed one.

I see this so many times but without any analysis, whatsoever, of the reasons/causes.

Are these items made to the wrong sizes for components or are rapidly wearing (even possible scoring)? Or is it simply the poor quality of the seals?

The former is a definite scrapping situation, but if it is only the seals, it would be an effective (and cheaper) repair to simply replace those seals with good quality ones. Indeed, if the seals are of the same dimensions as those of the more expensive replacements, it may be more economical to buy the cheaper and fit good seals in the first place.

[ManyMinors]

……
When I bought my Minor it had recently been fitted with a new aftermarket master cylinder and it failed quite quickly. I soon replaced it with a Lockheed one.

I see this so many times but without any analysis, whatsoever, of the reasons/causes.

Are these items made to the wrong sizes for components or are rapidly wearing (even possible scoring)? Or is it simply the poor quality of the seals?

The former is a definite scrapping situation, but if it is only the seals, it would be an effective (and cheaper) repair to simply replace those seals with good quality ones. Indeed, if the seals are of the same dimensions as those of the more expensive replacements, it may be more economical to buy the cheaper and fit good seals in the first place.

Well, that is a point of view, but as my car is used daily and I want it to be kept up to a good, safe and reliable standard, I'd rather not have cheap pattern parts on it - especially in the braking system. I'm perfectly capable of fitting a seal kit but there is no seal kit available for these pattern cylinders as far as I could see and anyway - since it was probably the seals which had failed in the first place that didn't seem a sensible option. It isn't a quick job to replace the master cylinder and I for one would rather do it just once, hence my decision to purchase a new one of known good quality. If others have the time and inclination to attempt to mend cheap, poor quality safety related items then that is their choice of course. I have previously dismantled a pattern wheel cylinder to find the design completely different to the original so new seals were not an option. I suspect the same would be true of the master cylinder.

[oliver90owner]

You are likely quite right, but I was just enquiring if any fault analyses had been carried out.

IF it is only the seals and good ones could be sourced, it would be a sensible option for me as I have precision tools to measure and the ability to install hydraulic seals. I’ve installed hundreds of seals over the years. Scored component parts are never a good sign, but even those could be re-machined if a replacement was simply not available.

I await to see if anyone has actually investigated the master cylinder failures. I always investigate before replacing such seals, but have never yet come across a cheap chinese aftermarket brake master cylinder for a Morris Minor.

I would not wish to buy one if they are not safe, or not able to be made safe before fitting. I’ve had too many failures, with single circuit brakes, to last me a lifetime!

[ManyMinors]

I discarded it I'm afraid - on the basis that I have more than enough old bits which I've kept on the basis that they "might be useful one day"! If I still had it I'd happily let anybody have it to strip down. Despite being fairly new, I was having to top it up about once a week so I guess it was poor quality seals - or maybe a scored bore which had lead to a damaged seal? Who knows. Either way, I had neither the time or the interest to strip it down. I agree that it might have been perfectly possible to rescue it, but that wasn't a path I wanted to take with something so vital .

The most distinct external difference between the pattern and Lockheed M/cylinders seems to be that the filler cap of the pattern ones has a fairly plain square top as opposed to the "Lockheed" lettering and hex top of the genuine ones.

[serowman]

I have pattern M/CYL but it has been resleeved with a stainless sleeve and it is working perfectly,I guess back to standard size

[jagnut66]

If in doubt replace it with a good quality replacement item.
Brakes are your lifeline.......
You could always refurbish the original if you so wish to (and, if once cleaned up, it's not found to be beyond redemption) and keep it as a spare.
Best wishes,
Mike.