MGB: 79 brake master cylinder

Trying, again, to rebuild the master cylinder of my 79 midget. Can someone tell me how to take the spirolox ring off the primary piston? The ring is solid. Do I just pry it off?

Thanks a bunch!!!

Never mind, I got it. Should always use my glasses with tight work!

That's a tricky little burger!! I couldn't make any progress on it while trying to compress the spring with one hand and work on the spirolox with the other. So I made a spring compressor; a piece of steel with three holes, two bolts and nuts with washers as needed. I cut the center hole large enough to pass over the cylinder and small enough to catch on the spring. The other two holes were drilled to match up with the spacing of the ears on the mc body. I ran bolts through these hones to the holes in the ears then was able to use nuts to tighten the compressor down until the spring was no longer a bother. Now that I could concentrate on the spirolox I could see by looking very carefully at the spirolox that there is an angle

Good - I lost a fairly lengthy post trying to describe how to look at the spirolox just right to see how it is removed.
Good luck

Sorry. Got the job done.

It might be nice if you could share your experience for others so that in the future they don't have the same problem.

jh180iq Wrote:

I'll try here Jonathon,
I rebuilt the brake and clutch master cylinders while I was at it. To get the masters out you must remove the MC bracket from the body. Remove the MC form the bracket. Now is the time to put your reading glasses on! Depress the spring into the MC including cap to expose a solid looking ring, which is the spirolox. I pushed the spring down by hand then clamped vise grips above to have freedom to get the spirolox off. Now remove the spring and cap. I line everything on my bench as removed to ease in reassembly. Now the circlip, I used surgical tools to remove Next I tapped the the end of the rod on my vise, MC up to remove the plastic guide sleve. Some say you have to melt it out, I got lucky. Later there was another circlip and finally the thing comes apart. Depress the next spring to take out the pin holding the expansion strap. Nominclature and spelling is mine, maybe I'll copywrite.
Look for deep pitting, mine was good, I did hone and used 320 grit sand paper rolled onto a rod. I also sanded the surfaces where the tank mounts.
Anyway, the hardest part putting the thing back together is the inner spring, at least when you don't have a spring compressor. I compressed the spring in an adjustable wrench and tied 12 lb fishing line on both sides to keep it compessed for reassembly.
Clean everything real good, I used brake cleaner. Also coat heavy with DOT 4 break fluid putting it back together.
One last note, I was concerned stretching the new rubber over the metal, but it turned out fine.
Hope this helps in the future.

Very much so.

I'll have to do this eventually. Now I know where to look.

Thanks,
Jonathan