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MG MG Y Type - Brake Master Cylinder rebuild

I would like to service the Brake Master Cylinder. Does anyone know if a rebuild kit or necessary componants are readily available to rebuild a Y Type Master Cylinder. I am reluctant to remove the Master Cylinder until I have the necessary parts. Preferably an Australian supplier. Are there any other vehicles that use the same Master Cylinder. Any advice would be appreciated

Terry Ciantar
T J Ciantar

Terry

Assuming the actual cylinder is in good shape, and does not need sleeving, then you need Lockheed Master Cylinder Repair Kit KL.71410 for a Y/YT or KL.71408/BMC 8G7103 for a YB.

I am assuming it is for a Y/YT in which case it is common to Allard (1947/48) P1, P2, K2, K3, M2X, J2, J2X, Alvis 3 Litre TC/108/G, Armstrong Siddley 18hp, Austin A.125, A.135, Princess III (1953/56), Bristol 400, 401, 402, 403, 404X, Arnold-Bristol 405, 407, 408, (1961/62), Frazer Nash 2 Litre Sports, Le Mans Mk II, Mille Miglia, Targa Florio (all models fitted with knock on wheels only), Humber Super Snipe IV, Pullman Mk II Mk IV, Imperial Mk i & II, Jaguar XK120 and XK 140, ... etc.

Your best best would be to clearly try the Jaguar XK owners club in Australia ... unless you have a good auto factor who an order based on the Lockheed refernece number.

Good luck Terry.

A great sourc for this sort of thing is the Alternate Parts List that can be downloaded free of charge from the left hand side of the NEWS page at www.mgytypes.org.

Paul
Paul Barrow

Terry, I purchased my Lockheed kits from Automotive Surplus in Mitcham Melbourne. Phone 03 9873 3566
e-mail sales@autosurplus.com.au They despatched the correct kits for the Y Type master Cylinder promptly and at a reasonable cost. Mel Fry Y5103
M.H. Fry

Thank you Paul & Mel, Paul you are correct in assuming that it was for Ya. I'm hoping that I will find the Master Cylinder in reasonable condition and with a bit of luck would have been resleeved in stainless. I have just completed the wheel cylinders which was a very straight forward job as they had been resleeved and rubber parts obtained locally. Thanks again.
Terry
T J Ciantar

Bingo! Thanks Mel. Automotive Surplus can supply and as you said very reasonable price.

Terry Y2866
T J Ciantar

Based on that I have added them to the links page for future reference too so thank you Mel and Terry.

Paul
Paul Barrow

I have a spare master cylinder if you need one Terry, or if you want to re-build in advance.

I had one re-sleeved in stainless just before Easter at Knight's here in Brisbane for $100 (including supply of seals & machining the piston).

Tony
A L SLATTERY

Thanks Tony, I'll keep that in mind and contact you off line if I run into trouble when I remove mine and see what condition it's in. I'm hoping that it has been resleeved as were the wheel cylinders.

Terry y2866
T J Ciantar

When I fitted new seals to my master cylinder I was pleased to see that it had already re-sleeved with stainless steel, however the previous owner had missed drilling the by pass port, they must have been puzzled when the new brakes came on and stayed on............

Drilling the hole through the filling hole was difficult and a required using a pin vice to hold the small bit and reach down to the sleeve.

Regards,

Brad
B Wilson

When fitting the outer concertia cover/rubber boot there is a little hole in it which should be pointing to the ground - see MG Service Department Service Sheet Amendments (#68)PDF on the News Page (left margin Downloadables) PDF at www.mgytypes.org.

Paul
Paul Barrow

Hello Brad, in a way you have hit the nail on the head. Although for a slightly different reason. I commenced the brake overhaul due to a problem with my brakes staying on after I apply them. All four brakes would stay locked on and on releaseing any one of the wheel cylinder bleeders fluid would spurt out under some preasure then all would return to normal position. As stated earlier in this thread the wheel cylinders have now been overhauld. I have owned the car for some years and the brakes had been working well so I assume I will find the return bypass port is full of crud which is stopping the fluid return. Looking at the workshop manual the bypass port does indeed look very small and would be easily blocked. Should know for certain within the next week.
Paul, would I be correct in assuming that the hole in the outer rubber boot is to allow any fluid which may leak, to drain out of the boot?


Terry Y2866
T J Ciantar

I am replacing my Master Cylinder at present due to a slow leak from the secondary seal.

I discovered last night that the breather hole in the cap was completely blocked - it took a very small drill and a few minutes to clear the original hole, so I got to thinking - if this breather is blocked - what affect does this have on the operation of the Master Cylinder.

There was a lot of corrosion around the secondary seal, so was moisture being drawn in here to compensate for the blocked breather ?.

I know from experience that a vacumn is not tolerated, and the atmospere will find a way in there somehow !.

Refer to page L-3 of the CD workshop manual.

Over to those who might know for sure.
A L SLATTERY

Tony

As with all blocked breathers - they lead to a build up of pressure ... or of a vacuum that cannot then be released. A vacuum in the master cylinder tank will mean that the fluid cannot return properly into the tank when the pedal is released ... leading to brake lock up and possible boiling of brake fluid and a loss of effective braking.

Another tip to remember when rebuilding the brake master cylinder on a Y or Y/T is that there is a small hole in the rubber boot. This MUST go down towards the ground! See the MG Service Department Service Sheet Ammendments.

Paul
Paul Barrow

Just to add to an old thread, and to pick up Paul's comment - "...there is a small hole in the rubber boot..." -I have two new boots, one marked PBR Made in Australia, and one received this week specifically as a YA master cylinder rubber kit from NTG (whom I respect greatly).Neither has the weep hole! I can only presume that it is a multi-brand, multi-purpose boot, and that not all applications need the little hole.
So this is just a note of caution to all Y-typers, to follow Paul's earlier advice, and make sure that a weep hole is provided - or fashion one before assembly!. Regards, John.
J.P. Hall

All, as this thread talks about Master Cylinders, I thought I would draw your attention to a YA Master Cylinder being advertised on eBay....It clearly is not a YA M/C as the advert stipulates. The reservoir is much flatter and smaller than proper YA one which is larger and square in shape.

http://www.ebay.co.uk/itm/MG-YA-MASTER-CYLINDER-ORIGINAL-/382223728370?hash=item58fe4f3ef2:g:eRkAAOSwHm5ZtVXw

I have told the seller and also spoken to NTG too as they are referred to as the ones who have refurbished the unit.

Richard
R E Knight

Agreed Richard - not an YA/YT Master cylinder and thank you for flagging that to the seller. It may well have come off a Y that they broke recently ... but it is nor original equipment for sure.

While on the subject though of brake master cylinders, the only people I entrust with Y/YT master cylinder Rebuilds (even though they a re half a world away) are C&C - see http://www.mg-cars.org.uk/imgytr/links.shtml#Brake / Friction Systems for a link to them.

Paul
Paul Barrow

C&C rebuilt two of my M/C for the YT and did good professional job. One now fitted and doing good job on the car, one for the spares shelf.
R E Knight

Just a thought - is the fluid return bleed hole clear, it was overlooked when my master cylinder was re-sleeved, and so I drove around Brittany with the brakes partially on. Bryan
B Mellem

This thread was discussed between 09/05/2011 and 14/09/2017

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