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MG Midget and Sprite Technical - Leaky hydraulics!!

HI,

I can't seem to get my brakes not to leak!

Car is frogeye sprite.

Bought a new master cylinder with 3/4 size pistons like five or so years ago, new rear wheel cylinders and converted to discs in the front with new callipers.
New steel braided hoses and new pipes all around.

But now i can't seem to get it tight, and I can't identify the leak. I bleed the breaks and when i took it for a drive i lost the hydraulics completely so it's just not air left in the system.

The inside of the drums are dry so no "hidden" leaks inside. And no obvious leaks anywhere else.

Is my new master cylinder failing, or is it the pipes somewhere..?

This is literally the last thing to sort after a seven year long restoration, expect for breaking in the motor and I'd really rather start on that..


Regards Alex
Alexander Sorby Wigstrom

If there are no leaks, try bleeding again and then see how the pedal reacts to prolonged pressure. It does sound like the MC is suspect.
dominic clancy

When you say leak, are you losing your fluid?

Do you know what make the master cylinder was? TRW, or AP Caparo?
Dave O'Neill 2

Alexander,
You bought the brake cylinders 5 years ago an did not use it. Most probably the rubber started sticking to the cylinders in those 5 years and is damaged in first use. So it leaks internal. As Dominic writes; no leaks so is sounds like de master cylinder. Take it apart first.

Flip
Flip Brühl

I agree with flip

but another possiable area... is the bleed nipple on the calipers ... sometimes if th3 threads are worn it can leak past the breed thread.

if thats the case wrap the threads in ptfe tape
prop

Alexander

Dave is asking for the brand of Master cylinder as there have been many reported problems with TRW Master Cylinders.
I did take issue with TRW at a Trade show. I showed them the MGA thread on this site when I got the usual response to complaints. The MGA uses the same master. Apparently Classic Car parts only consist of 8% of their trade. The Masters are made in China then shipped to retailers not even touching base with TRW.

Have you fitted Morris Minor rear brake cylinders with your conversion
As in times past those converting to discs complained of a soggy pedal until MM rear cylinders were fitted.

The idea of using PTFE tape on a bleed nipple will not work. If the nipple bleeds then fluid is passing through the seat due to wear or debris. It will pass the initial reduced diameter of the nipple then into the hole accessing the bleed tube.

Alan
www.masckent.org
Alan Anstead

If you have Frogeye back plates fitted then a suitable replacement cylinder is any 62+ Morris Minor slave cylinder. Identical to a Frogeye except 0.750 bore..
The AP part number is LW11287
Alan
www.masckent.org
Alan Anstead

As Alan says TRW are known to be a problem. I had one leak straight out of the box, but it was obvious as fluid was on the pushrod and dripped down into the footwell. Got it replaced after returning it but still had to adjust pushrod to get it working properly. I would only buy Caparo in future.

Trev
Trevor Mason

I've got no idea of what make it is but well I've orderer a rebuild kit for the MC. Thanks for your input

Alan, i've already got the minor wheel cylinders sorted but thanks!

/Alex
Alexander Sorby Wigstrom

This thread was discussed between 16/06/2016 and 18/06/2016

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.