Triumph Herald 1200 Leaking Master Cylinder

[Bordfunker]

I refurbished the brake master cylinder on my Herald 1200 a couple of months back after discovering a leak while cleaning up the bulkhead.

 

I replaced the seals and reassembled the cylinder, and everything looked fine, however I have now noticed that it is leaking again.

 

Having checked the piston seal, this is fine with no sign of a leak.

 

Which leads me to suspect either a hole in the cylinder casting itself, or more likely a leak at the union from the cylinder to the brake pipe.

 

Having looked online I can see complete brake pipe kits, but might really only need a couple of unions and a length of pipe made up.

 

Can anyone suggest where to get these?

 

Thanks

 

Karl

[dougbgt6]

I would undo the union, there may be crude inside from when you took it apart before. Do it up tight and see if it still leaks. There are motor factors about who sell ready made short lengths and there's also Ebay, this sort of thing  http://www.ebay.co.uk/itm/Brake-pipes-made-for-Classic-cars-Lotus-MG-Rover-Triumph-3-16-Cunifer-up-to-60cm/291917364242?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D2%26asc%3D38661%26meid%3D179381c88ef940cab2beb071dffb702a%26pid%3D100005%26rk%3D1%26rkt%3D4%26sd%3D291917364250

[Clive]

Many places will make you a pipe up to length for a few quid. When measuring don't forget to allow extra so a coil "pigtail" can be incorporated (it allows for movement)

However, are you sure fuid is not escaping from the lid? I have had that where the seal was not doing its job..... amazing how much the fluid gets splashed about in the reservoir.

[Pete Lewis]

Loctite also make a hydraulic seal for pipe and unions theres a whole range to suit

pressures , fittings and cure times

They can be useful on some problems

 

pete

[Bordfunker]

Thanks for all the advice guys.

 

Doug, the union itself is pretty chewed up, and looks damp where the pipe exits, so I'm fairly happy to replace it.

 

Clive, the lid is also suspect as pointed out by the missus who was assisting with the pedal pumping.

 

This is the type of master cylinder I've got, and the metal,lid that sits at the base of the clear plastic top is corroded.

 

 

Pete, I may get some of those in as useful standby.

 

Thanks again

 

Karl

[Pete Lewis]

Guess thats a 5/8"bore 0.625"

 

later were 0.7" on type 16 calipers ( might be on the type 14s)

 

there are very cheap landrover specd cylinders that are the same base design but 0.75" so less stroke but higher pedal load , you dont really want a .75 on a .625 but many use them and at under £15

Its economical but not quite correct

 

they are same fit but need the orig pushrod swapping over

 

pete

[Bordfunker]

I just nipped out to the garage to take a look, and it's definitely the lid which is leaking.

 

I'll try drawing the fluid down and replacing the cap seal.

 

Karl

[Pete Lewis]

The plastic top extention is to allow some visual warning capability it also increases the resv. volume

but does add one more area to leak , you could delete the extention and fit a solid cap

but like many then you must remove the cap to check the levels

 

Pete

[Casper]

 

 

The plastic top extension is to allow some visual warning capability it also increases the resv. volume

 

Mainly to increase capacity for (originaly) optional disc brakes.  I wouldn't run discs without either the extension or a larger M/C resevoir

 

C.

[Andrew]

Guys

Can I just add a comment. I have a 13/60 and had exactly the same issue with my MC leaking. I don't want to Appear clever do what I did buy a replacement MC complete as then you know the bores and the seals are new. The new one is a plastic reservoir but that is the point you can see the fluid level.

From memory the new MC was approx £40 from

 

Regards

Andrew

[Andrew]

The last word was supposed to be Fitchets

Andrew

[Pete Lewis]

There also places like merlin motor sport and car builder solutions where you can get a compatible Mcyl

and a bolt on or remote more modern larger plastic reservior

Just an alternaative

 

pete

[Bordfunker]

Thanks for your suggestions guys.

 

It looks like the fluid is leaking out from the thread on the alloy cap, so I might be able to get away with replacing the runner seal, which I didn't bother replacing when I rebuilt the rest of the cylinder.

 

The reason I didn't replace it was because the cap was stuck firmly on, and so I left as is.

 

Lesson learned!

 

Karl

[Pete Lewis]

Metal caps on alloy cylinders can become one and many left unattended are in need of giant gland nut pliers to get them removed

On the christmas list get a pair of 16" gland nut or slip joint pliers always good for oil filters fitted by gorilla's and things tight like caliper pistons etc.

 

like

http://www.ebay.co.uk/itm/Neilsen-Slip-Joint-Plier-Water-Pump-16-400mm-Brake-Calipers-Pliers-Grips-8Q-/281067745979?hash=item4170f172bb:g:6yQAAMXQyY1TSQ2K

[Colin Lindsay]

You can buy replacement MC from any motorsport suppliers, mostly clear plastic if you're not worried about originality.

Similarly if you want to keep the original setup with the plastic extension, fitted for the extra fluid required when brake discs were introduced, you can get replacement seals to stop any leaks. Mick Dolphin had some of the metal tightening rings as NOS a while ago, so they're still available. 

[Bordfunker]

Thanks for that Colin.

 

For now I've simply removed the plastic extension and metal sealing ring, and cleaned both up to remove 40+ years of crud.

 

I did drain the fluid down to below the level of the plastic extension piece in the MC.

 

I also cleaned up the thread on the MC itself with a wire brush, having first plugged the reservoir to stop contamination of the fluid.

 

Next up was fitting the rubber seal itself, which was obviously designed for the MC without extension, and therefore featured too small a diameter central hole.

 

Out with a craft knife and a circle template, and 5 minutes later we have an appropriately sized seal.

 

The whole lot has be put back and the fluid topped back up.

 

Hopefully that will be the last we see of the leak, but time will tell.

 

Karl

[Bordfunker]

Apparently not!

 

The MC has started leaking even worse than before, no doubt due to me removing crud that had helped keep it fluid tight!

 

Time to bite the bullet and buy a replacement.

 

So 15 minutes this afternoon spent removing the MC and mounting bracket, leaving me with this.

 

 

The sheen is from all the brake fluid that has leaked out.

 

I'll have to give it all a wipe down with White Spirit.

 

Karl

[dougbgt6]

Karl, WHERE is the rubber boot to cover your clutch pedal?!! You wanna keep the heat out the cabin? You godda have a rubber boot!

[Bordfunker]

Given that I don't currently have a heater, that missing boot is part of my master plan to find alternate heat sources!

 

Joking aside I will be refitting the boots to both brake and clutch when I've finally sorted out the leaking brake MC.

 

Karl

[Pete Lewis]

water good for brake fluid removal

and corroded battery terminals use a boiling water

 

pete

[Bordfunker]

Have they changed the formula of brake fluid over the last 25 years?

 

I remember that brake fluid used to strip paint at the merest contact when I had my Mini back in the early 90s.

 

I'll give it all a wash down ahead of the new MC turning up later this week.

 

Karl

[dougbgt6]

Are we talking dot 5 silicon fluid here? This is daja vu all over again.     

[Pete Lewis]

What colour is the fluid,

the std is dot 4 for these cars which disolves in water its a semi clear syrupy colour like a thin oil
So is dot older 2 , 3 ,and later 5.1,

dot 5 is silcon normally a bright coloured does not disolve in water

pete

[Casper]

And it also depends which paint you have.

 

C.

[Bordfunker]

Pretty sure it's Dot 4, but too cold to go out to the garage and check!

 

As for the paint on my Mini it was standard crappy early 80s Austin Rover fair, and very soft.

 

Karl