15 replies to this topic

[Compdoc]

I'm just refurbishing the seals on the brake master cylinder of a 1996 SPI, the one with with a servo attached, and have managed to crack the plastic reservoir, which seems very brittle.

I can get the whole master cylinder from Mini Spares for £80, but after lashing out £20 already for the seal kit I am a bit reluctant. The reservoir is shown on Mini Spares diagrams but is NLA.

I think Mini Spares buy these direct from Caparo (AP Braking) and pretty much every other part is available except the reservoir, which seems strange as Caparo must be manufacturing them to fit on the new master cylinders. Tried Caparo's website but they don't appear to sell to the public.

Anybody got any ideas, perhaps new old stock somewhere, or are these master cylinders fitted to any other vehicle? Reservoir part number GRK6010.

[Spider]

I've never found them anywhere as a separate spare part.  Might have better luck finding a good used one. The Plastic should be on the soft side but they do get brittle with heat and / or age.

[Compdoc]

Oh well, it looks like I'm just going to have to bite the bullet and buy a new complete master cylinder. Teach me to be a bit more careful in the future. Thanks for your help.

[tiger99]

Have you tried all the Mini suppliers including Somerford, Bull Motif etc? Just because Mini spares don't have it doesn't mean that others don't still have stock.

And yes it must still be made. They do break, and if the suppliers were serious about wanting to stock them I suspect that the manufacturer would oblige.

However there has been a trend for some years now to not supply parts for hydraulic assemblies, only the complete items. You can't easily buy seals, for instance, for the majority of cars now. The reason is largely due to fear of legal liability when a busy mechanic changes seals in less than perfectly clean conditions and a brake failure follows some time later, plus the fact that we have become a disposable society and despite considerations of recycling, no-one really wants to fix things now if they can just throw them away and charge the customer for much more than he needed. The Mini world has not seem much of this as yet. Enjoy being able to get individual parts while you can!

[Dusky]

And generalisation once again. *Sigh*

Complicated, I'll have a look to see if I have one that's good to use.:)

[Compdoc]

And generalisation once again. *Sigh*

Complicated, I'll have a look to see if I have one that's good to use.:)

Thanks for the offer Dusky, but I ordered a new master cylinder this morning. I did try a lot of suppliers for the reservoir, but none had stock. Hens teeth were mentioned a few times.

[tiger99]

Well maybe if they read this, they will waken up and do something about the situation. Especially if we could get some feel for how many people might need a new reservoir....

As a last resort, not suggested in this case, fittings are available to connect flexible pipes to the master cylinder reservoir ports, and you can get plain reservoirs for remote mounting. Kit car people tend to need stuff like that. You can even get a triple reservoir, the bulk of which is shared but at the bottom it is segregated into two brake and one clutch compartments, so you have only one thing to fill.

[Compdoc]

Well maybe if they read this, they will waken up and do something about the situation. Especially if we could get some feel for how many people might need a new reservoir....

As a last resort, not suggested in this case, fittings are available to connect flexible pipes to the master cylinder reservoir ports, and you can get plain reservoirs for remote mounting. Kit car people tend to need stuff like that. You can even get a triple reservoir, the bulk of which is shared but at the bottom it is segregated into two brake and one clutch compartments, so you have only one thing to fill.

I did find out that a few other manufacturers used the same master cylinder, but believe it or not, all used a different design of reservoir. The most interesting one was Morgan that used two giant reservoirs that would need holes cut in the bonnet to fit a mini. As you say, lots of the kit car parts suppliers had remote reservoir kits but not far short of The £80 mini-spares are charging for a complete master cylinder.

[tiger99]

Sad. Daft even. Standardisation is good for everyone because it saves money.

[ryomini]

Compdoc, when removing the reservoir do you just pull the pin at the bottom and lift it off

or can you even leave the pin in there and just pull it out of the seals

I think I have the same problem, mine seems to be leaking from the rear seal

and like you seems to be a pity to have buy a whole unit

I have never dismantled this item before

do you have a photo log of the work you did ?

[tiger99]

The pin is what is positively locating it and has to come out first.

[Compdoc]

Compdoc, when removing the reservoir do you just pull the pin at the bottom and lift it off

or can you even leave the pin in there and just pull it out of the seals

I think I have the same problem, mine seems to be leaking from the rear seal

and like you seems to be a pity to have buy a whole unit

I have never dismantled this item before

do you have a photo log of the work you did ?

I don't have any pictures as it was supposed to be a 2 minute job. But at Tiger99 says, you have to pull the pin out first, then lever gently the reservoir stubs out of the rubber seals, which are surprisingly tight. Try to keep the reservoir level to keep stress of the stubs. Replacement seals are part of the master cylinder repair kit, around 20GBP.

[ryomini]

Thanks for that extra info

actually mine seems to be leaking from the 'o' ring that goes between the master cylinder and the huge servo unit - I think I'll let my garagist handle this one

[Compdoc]

Thanks for that extra info

actually mine seems to be leaking from the 'o' ring that goes between the master cylinder and the huge servo unit - I think I'll let my garagist handle this one

That large "O" ring is just an air seal. There is another seal a little bit further up the cylinder which stops the fluid. So you probably need at least a repair kit if the cylinder bore is smooth, or at worst a new master cylinder. I would get your mechanic to check the bore first before ordering a repair kit, the last two Mini cylinders I have dismantled have had damaged bores. Or maybe I'm just unlucky!

[tiger99]

No, you are not just unlucky, it happens to most of us. With the age of all Minis now it is very common for all the hydraulic cylinders including the master to have serious wear and need replacement. With calipers the seal mostly slides against the piston (it sort of shuffles about slightly in the groove), so it is the pistons that are usually needing replacement. Rear wheel cylinders are usually not fit for re-use as they corrode. Big Red do good reconditioned calipers, but economics dictate that in most cases, except rare cars, wheel and master cylinders are disposable.

In view of the fact that the entire hydraulic system is only a small part of the cost of a restoration, and it's importance, it doesn't hurt all that much to have to replace the lot. I have had to do that on several cars including Minis.