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MG MGA - Master cylinder - repair or replace

I have been sorting out my brakes (again) and after losing brake pressure while driving decided to refurbish the brake/clutch master cylinder. I discovered that both bores have a rough patch about half way down.

Is it better to get my Lockheed m/c resleeved or just buy a new one from Moss? Can anyone recommend who can do the resleeve job?

Would it be possible to clean up the bore with a reamer? If so how much can be shaved off from the 7/8" bore and still give a good seal? On the other hand it would probably involve buying several reamers as the adjustable ones probably won't reach the bottom of the bore.
Dan Smithers

Hi Dan,

I had mine re-sleeved in stainless back in 2007, I am using silicone brake fluid and have had no problems.

The company I used was Contract Autoengineering Ltd at Stourport On Severn. Tel 01299 828117. The cost back then was £99.58 all in.

Regards,

Andy
Andrew Dear

In my opinion it's not worth re-sleeving.

A new Lockheed (AP) master cylinder is £133.50 and a new TRW is £85.00, both delivered. Personally I can recommend the Lockheed master cylinder. I put one on my car five years ago and use silicon fluid. Some have reported problems with the TRW master with stiff seals, but obviously there's quite a cost difference in price.
N McGurk

Hi Dan,
Try Ryans Classic Car Parts,they have AP dual master cylinders for an MGA for £100.plus £5. p&p.
Regards,
Steve A.
S Ash

Dan

Neil has said it. Get a Lockheed AP (Caparo AP). Well worth the extra money. Beautifully engineered. Leaves Moss and others standing. It solved all my MC problems. Bob West will not touch any other MC. He keeps them in stock.

As I understand it, Caparo bought the tooling off Lockheed, but unlike Lockheed, take greater care in their engineering quality control. The bore finish is far superior. I have had the 2 versions side by side and examined them. I am not a professional engineer, but the difference in finish was obvious even to my eyes and feel.

Steve
Steve Gyles

Thanks for your advise. I have ordered one from Ryans.

dan
Dan Smithers

I was looking at the old m/c last night and decided to take the top off.

Inside, I found that the two channels in the bottom of the reservoir had a thick layer of something that looked like dark mayonnaise in them. Does anyone have any ideas what this is and what would produce it?

I use DoT 5 silicon fluid.
Dan Smithers

Dan

Has your system always been silicon? If not, it is possible that it was not properly flushed of other fluid before changing over. This would also include changing EVERY seal throughout the system and the flexible hoses. If this is the case then the residue could be the resulting contamination. Read the article I posted below in 'DOT 5 or DOT 4 Brake Fluid?'.

Looks like you would be well advised to do a thorough flush through and change all those seals etc before fitting your new MC.

Steve
Steve Gyles

I ordered one from Ryans, and it eventually arrived (after I was sent a seals kit which I returned). It's a TRW one marked Sprite/midget/MGA/Frogeye.

Presumably the Spridget configuration is the same as MGA. Is there any way of checking that the non-return valve is on the correct side?

Their website shows pictures with the Caparo AP logo on it.
Dan Smithers

Dan

It does not sound like a Caparo AP to me (http://www.caparoapbraking.com/)

Sounds more like a Lucas-Girling-TRW.

Steve
Steve Gyles

I ordered the AP Caparro M/C from Bob West for my '59 A. When installing it, the brake line nipple that screws into the M/C wouldn't fit. I had to find and use a spare nipple off another brake line to make it work (which means I had to cut the brake line, install the new nipple, then braze the line back together).

Perhaps I ordered, or received, the wrong M/C. Whatever, it was not an option to send it all the way back to England.
JM Morris

Dan, send it straight back and demand the AP unit you paid for or a refund. Either a genuine mistake from Ryans in which case they will be happy to sort it out, or they are deliberately misleading customers. An easy way to tell the AP units is they use the original type slotted cheese head screws as oppose to the hex head type.
AP
http://www.ebay.co.uk/itm/MG-MGA-LOCKHEED-NEW-BRAKE-CLUTCH-MASTER-CYLINDER-/150737537800?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item2318a84b08#ht_1387wt_1165
TRW
http://www.ebay.co.uk/itm/AUSTIN-HEALEY-SPRITE-MIDGET-MK-1-MGA-BRAKE-CLUTCH-MASTER-CYLINDER-/230704932318?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item35b715e5de#ht_499wt_1185
Ryans, clearly advertised as AP Caparo
http://www.ebay.co.uk/itm/AP-BRAKE-MASTER-CYL-SPRIDGET-58-63-MGA-/260805882096?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3cb93df0f0#ht_499wt_928

So far it looks like they have mislead you and charged you £20 over the competition into the bargain.
N McGurk

This thread was discussed between 23/01/2012 and 10/02/2012

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This thread is from the archive. The Live MG MGA BBS is active now.