Master cylinder pitting

[38plymouth]

I ordered a master cylinder rebuild kit from bernbaums and just pulled the master cylinder out of the car and there is some pitting inside. I've been hitting it with a hone but I'm not sure I'll be able to get it all out. Two questions before I have to spend almost $200 on a master cylinder and wait for shipping g. Is any pitting acceptable? And secondly what if I keep honing it to get 99% of the pitting out could I hone it too much? I can feel the pitting with my fingernail but it's not what I consider real bad. I really wanted to have the car put back together this weekend I had to pull the floor pan out to get the master cylinder out the easiest way. I do want it to be correct though and don't want to have to do this again.

[Los_Control]

Mine did not look terrible, I honed it out good. When installed I bled them and felt fine ..... then I pretended to do a panic stop and stomped on the pedal.

Went straight to the floor. .... Question is, how many times had it been rebuilt and honed before I rebuilt it?

 

I am not completely stock, I felt it was a good time to just upgrade to a two stage master .... instead of having my original master re-sleeved.

If you want to stay stock I would vote for having yours professionally re-sleeved, and avoid the painful curse of modern offshore parts quality.

[Sam Buchanan]

2 hours ago, 38plymouth said:

I ordered a master cylinder rebuild kit from bernbaums and just pulled the master cylinder out of the car and there is some pitting inside. I've been hitting it with a hone but I'm not sure I'll be able to get it all out. Two questions before I have to spend almost $200 on a master cylinder and wait for shipping g. Is any pitting acceptable? And secondly what if I keep honing it to get 99% of the pitting out could I hone it too much? I can feel the pitting with my fingernail but it's not what I consider real bad. I really wanted to have the car put back together this weekend I had to pull the floor pan out to get the master cylinder out the easiest way. I do want it to be correct though and don't want to have to do this again.

 

There are places where budget decisions can be justified but brakes are not one of these. Spend whatever money is needed to put your brakes in tip-top condition, your lifespan might be altered by saving a few bucks......

 

And to address your question...in my opinion pitting in a brake cylinder is totally unacceptable.

Edited February 16, 2024 by Sam Buchanan

[38plymouth]

Well turns out I was worried about nothing the pitting wasn't anywhere near where the rubber cups and seals are. And It cleaned up in just a couple of minutes with a hone. I guess it looked worse than it was.

Edited February 16, 2024 by 38plymouth

[Sniper]

Glad to hear you got it sorted out. In case anybody else is looking at this in the future there are companies out there that will sleeve your old master cylinder. I don't know how much it cost but it might be cheaper than 200 bucks

[Eneto-55]

Another possible option might be to get it plated back to just a bit smaller ID than original specs, then have it reamed out.  I have no idea how costs would compare to sleeving.  There are challenges to electro-plating the inside of a bore, but this case is large enough that it isn't that difficult. 

 

However, the things we bore plated were done using cadmium, not industrial chrome.  Except I don't really know that they never bore plated in the chrome section of the plating shop where I worked - I was seldom asked to work on anything chrome - just small pot metal pieces - mostly fishing reel handles. How would straight hot nickel hold up? (We plated oil-field flipper valves with that method, and that process might put the material on more evenly than the other type of plating.) Is stainless steel better than industrial chrome?  Questions I do not know the answer to.