Front master cylinder piston removal

[chrisg]

Hi all, I'm looking for the best way to get the front master cylinder piston and seals out ?. Circlip removed, but its solid. Soaking in penitating oil at the moment.

[Shytalk]

No easy way if it's solid, might need to soak it for a while then try heating it, due to it's location the only real option is to run a drill down the centre of the piston as a last resort, it'll either come out or be scrap.

[chrisg]

Result, got it out with some heat from my decorators heat gun. Plenty of smoke 

There are 2 holes in the reservoir, 1 approx. 2mm and another tiny hole. Does anyone know what size the tiny one is, as its blocked and I need to remove the crud.

[oldbritguy]

Carefully use a straight strand of wire from a wire brush.
That’s what I have done in the past with success. Just make sure you don’t jam the wire or a bit will break off. Then you are in a bit of bother.
Use some brake cleaner as well to soften any crud which is blocking the hole then a good blow through with an air line.
Job done.

[JonW]

All good advice.

Make sure you check the bore as it may well need a hone, or at least a clean up. you can make up something to do that by wrapping some wire wool round and old drill bit and gently moving it up and down the bore. You need to get the corrosion out or it will not work well and youre wasting your time.

[chrisg]

Dec 14, 2020 23:57:22 GMT 1 JonW said:

All good advice.

Make sure you check the bore as it may well need a hone, or at least a clean up. you can make up something to do that by wrapping some wire wool round and old drill bit and gently moving it up and down the bore. You need to get the corrosion out or it will not work well and youre wasting your time.

Its soaking in penetrating oil overnight and I was going to polish the bore with some solvol auto sol on a rag. I have a wire brush, so I'll try that.

Thanks to all.

[JonW]

Hmm be wary of just sticking wire brushes in things. The bore should be basically smooth, cross hatching is ok but if you put a hard brush in it you could score it as its just soft alloy. Im not saying your brush will ruin it, but a gentle brush would work, hence why i suggested wire wool.

[chrisg]

Dec 15, 2020 1:12:12 GMT 1 JonW said:

Hmm be wary of just sticking wire brushes in things. The bore should be basically smooth, cross hatching is ok but if you put a hard brush in it you could score it as its just soft alloy. Im not saying your brush will ruin it, but a gentle brush would work, hence why i suggested wire wool.

The wire brush strand is to remove the crud in the small return hole, definitely not in the bore.

[chrisg]

Dec 14, 2020 23:01:49 GMT 1 oldbritguy said:

Carefully use a straight strand of wire from a wire brush.
That’s what I have done in the past with success. Just make sure you don’t jam the wire or a bit will break off. Then you are in a bit of bother.
Use some brake cleaner as well to soften any crud which is blocking the hole then a good blow through with an air line.
Job done.

Wire brush trick worked a treat , many thanks. I would have never thought of that.
I was going to get a tiny tiny drill.

[headcoats]

Or a tiny brass brush or some scotchbrite