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MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - Rear brakes parts

Car: IOW Frogeye with later 1275 Sprite rear axle.

I'm getting together parts to do a rear brake service and am looking for advice.
I plan to use Mintex shoes from Minispares, and see they also do rear wheel cylinders (GWC1102MS) at £7.80 These are not original parts and so I wonder if they are as good as cylinders from AH Spares (at £17.50) which I presume are to original spec.
I will have to do an order with AH Spares to get the Belleville washers and a few other bits and pieces.
Also can you let me know the thread size of the rear bleed nipples: I want to get speed bleeders from Demon Tweeks.
best regards,
Nick
J.N. Williams

Nick,
I wouldn't make any assumptions on quality just by price. I've no idea if the AH are good or at a high price. Also I think you are looking at the wrong cylinders at £17.50 +VAT, you want the £12.95 +VAT AH Spares XBRK182 - OE PART NUMBER: GWC1102. - https://www.ahspares.co.uk/austin-healey/sprite/brakes-xbrk101-to-xbrk210/wheel-cylinder-rear-2.aspx

Check you are buying the 1.25" Mintex, GBS834AF (unless you're going up to 1.5").

I am NOT one to promote Toss but I've had no trouble with their £10 GWC1102 I fitted two years ago.

The Mini Spares GWC1102 are "Genuine AP" at £13.28 and if you follow the 513118A link it shows the current 7mm (spanner size) bleed valves are same thread size as the previous 1/4" (spanner size) which is 1/4"unf thread.

http://www.minispares.com/product/classic/513118A.aspx

They also sell Lockheed Dot 4 brake fluid at £5.14, 1l (SSB9415) or £3.07, 500ml (SSB9413).

You can get the original belleville washers and circlips if you want but the E-clips are so easy to fit with following instructions that even I can do it.


Nigel Atkins

remove the bleed nipple from the brake cylinder

find a (pan head) machine screw to fit where the bleed nipple goes into the brake cylinder

use the (pan head) machine screw to secure the brake cylinder to its position on the brake backplate - but not tightly, *see later

- (or find any method to hold the cylinder in position without damaging the backplate, perhaps a clamp)

you now have the brake cylinder in position with both hands free

use a suitable flat blade screwdriver to fit the E-clip (concave side of clip to backplate)

get the tangs fitted *then place the blade of the screwdriver behind the E-clip to check for a bit of give

place the blade of the screwdriver between the cylinder and the backplate (looking at the cylinder drum side) and gently prize the cylinder to flex the E-clip, if its in correctly you will feel it trying to retract, if its not it will fly off.

- (see illustration below for concave side of clip to backplate)


The original Belleville washer and circlip are available from AH Spares Ltd - https://www.ahspares.co.uk/

o XBRK182C (circlip)
o XBRK182W (Belleville washer).



Nigel Atkins

Nick,
The size of the cylinder matters. It is just wat brake bias you want. I bought smaller than original and still needed a brake bias valve to prevent the rear wheels from locking first.
I use to buy brake parts at C & C special parts https://ccparts.nl their quality and advice is superior. They make most parts themselves.


Flip
Flip Brühl

Many thanks Nigel and Flip for your helpful comments and suggestions.

Nigel, quite right about the AH Spares wheel cylinder: I was looking at the wrong one. The Minispares Mintex shoes are the ones I saw.

Nick
J.N. Williams

note: on the last cylinders I bought the roll pin didn't align with the backplate...Dave
David Cox

Roll pin is in different places depending on what size the cylinder is. The cylinder is machined in one unit, so if the roll pin is in the wrong place it is extremely likely that the bore is wrong...
Rob Armstrong

The roll pin is in the opposite corner between 1500 and 1275 cylinders. Don't recall the sizes but presumably different as Rob says.
GuyW

the cylinders were bought for my friend's 1275...the only thing different about them was the position of the roll pin. The bore was the same but as they were assembled with a piston as a unit it surely wouldn't matter??
David Cox

Could it have been a cylinder for another make/model sent or ordered in error. Do Mini, other BL, ones vary.
Nigel Atkins

I'm pretty sure it was correctly ordered ...the bleed screw and inward line hole and cylinder block were identical...the roll pin was not in the right place. I guess it is just another instance of poor quality control. Where are these items made??
David Cox

Dave

As Rob has pointed out, there were (are) several different bore sizes of twin-piston wheel cylinders manufactured. Each size of wheel cylinder has the roll pin in a certain position, so it shouldn't be possible to unknowingly fit the wrong size of cylinder to any particular car.

If the wheel cylinders that you bought had the roll pin in the wrong position, then either they were the wrong cylinders, the cylinders were manufactured incorrectly, or the axle/backplates have been swapped at some point in the car's history.
Dave O'Neill 2

Dave O'N...that makes sense. Other than the roll pin being "misplaced" everything works fine.....well at least the car stops good and straight! Dave
David Cox

1500 rear axle would do this too... (if in one bit with the backplates)
Rob Armstrong

Nick

There are also specialist brake parts suppliers who are useful sources of genuine AP Caparo (Lockheed) bits, for example Powertrack Brakes Limited, Past Parts and Coastings Ltd.

Cheers
Mike
M Wood

This thread was discussed between 28/09/2019 and 16/10/2019

MG Midget and Sprite Technical index

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