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MG MGA - master cylinder sleeve - cracked?

has anyone had this happen to them???
I had my master cylinder resleeved about 6 years ago ( apple hydr. )and it started leaking a "little " the first year,I'm using DOT 5 so I figured I'd have to live with it, but it's gotten worse so I decided to put a rebuild kit in it. after disassembly I honed the cylinders with 220 then 400 grit stones, and I noticed what I thought was a long scratch on the brake side sleeve, more honing didn't remove it, looking closer I think it is a crack. is this possible? it doesn't run the entire length just about 2 1/2" in the center, seems to stop about 1" from the front.
any info is appreciated.
thanks joe
joe williams

Reading here over the years, the company doesn't have a very good reputation for long lasting or leak-free results, but maybe it's just a minority that have that probem .

What is wrong with a brand new cylinder - is your life really not worth the extra dollars to have brakes you can trust to stay working ??????
dominic clancy

It would be very surprising if a sleeve pressed into a MC body cracked. IMHO this would have to happen befor or during installation. I'd be tempted to contact the folks at Apple about this to see what they have to say.

G T Foster


As I remember Apple recommends against DOT 5. Apparently there is a possibility of leakage along the sleeve (?) with the DOT 5 fluid.

The line in the sleeve MIGHT be a weld seam if the tubing they used is manufactured from flat sheet by welding.

Please let us know the outcome. I am about to put in DOT 5 but I do have a new MC and rear slaves. Will rebuild the front (B) calipers before filling.



Larry Hallanger

Apple says not to use silicon fluid in brass sleeved cylinders. Silicon should only be used with stainless sleeves.

For what it's worth, I have been using a brass sleeved unit from Apple with DOT 3 for a couple years now and have had zero problems.

Mark J Michalak

I had the M/C on my 59 sleeved in brass (not by Apple) and converted to Silicon fluid, not having been advised otherwise. Working fine 2 years later. I'd be interested in any supporting rationale for not using Dot 5 with brass since I can't think of a reason if the sleeving is properly done.
Tom Heath

I took my MC to a friend with a 10X scope and he thinks it's a scratch not a break so I'm going to hone it some more to try to remove it

I'm thinking I may go with a new MC if this rebuild still leaks when I'm done.

Is your new MC from Moss?
is it the Lucas-TRW with the flat plate top?
if it is does the original raised top fit on it ok?

joe williams

This thread was discussed between 29/08/2007 and 05/09/2007

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