Rebuilding '62 Master Cylinder

[Kennith H.]

I've look back through the Archives and cannot locate a thread for rebuilding my master cylinder. BTW, I was able finally to remove the large nut by drilling a hole in my workbench with a forstner bit to accomodate the firewall end of the cylinder and holes for the three mounting bolts. I mounted the cylinder vertically on the bench and used an impact to remove the nut - man, was it ever on tight!

Now I have to clean and rebuild the cylinder. Does anyone have a lead on some instructions? From the Archive? Another site? I'm concerned partly with the 'easy' way to remove the keeper at the plunger end. Also, should I sumerge the unit in carb or other parts cleaner? If so, what do I clean that mess up with to remove the parts cleaner? Also, what size hone do I use for the cylinder?

Any advice or a push in the right direction would really be apprechiated,
Ken

[Christopher R.]

Re: Rebuilding '62 Master Cylinder

For about $200, you can send it out to somebody to have it done for you. The rebuilders usually sleeve the bore. White Post in Virginia and Apple in New York are the 2 popular ones. I had a bad experience with White Post. Others did also. You can find those posts from a few weeks ago in the archives.

The usual Corvette parts suppliers sell the rebuild kits for around $30. You'd have to hone the bore yourself. Don't know the size. But you can measure it. You can decide whether it needs to be sleeved by inspecting it. The rebuilding is no big deal. New piston and some seals.

Check the integrity of the plug on the front. Make sure it isn't going to pop out.

[Edward B.]

Re: Rebuilding '62 Master Cylinder

Read the previous posts on rebuilders before you decide where to send your master cylinder.

[Kennith H.]

Re: Rebuilding '62 Master Cylinder

I have the rebuild kit and would like to rebuild it myself. Whne I bought the car the last owner had decided to replace the engine with a high-output 350. Otherwise, the brakes worked okay so I am thinking just a hone to clean up the cylinder rather than having it sleeved, since I would have to send it out for sleeving and I've seen the posts that indicate this can be risky. This way I never lose sight of my correct, original master cylinder.

A real mystery to me is getting the snap ring our of the plunder end of the cylinder. Any advice?

[Steven N.]

Re: Rebuilding '62 Master Cylinder

If you want to re-sleeve, I recommend Apple. I have had dozens done there with no problems. Just tell them you want original core returned with the soft plug intact. Cyclinders are very easy to rebuild after that. I believe the st-12 has a chapter on rebuild. Good Luck !
Steven J.

[Kennith H.]

Re: Rebuilding '62 Master Cylinder

If you want to re-sleeve, I recommend Apple. I have had dozens done there with no problems. Just tell them you want original core returned with the soft plug intact. Cyclinders are very easy to rebuild after that. I believe the st-12 has a chapter on rebuild. Good Luck !
Steven J.

Steve, I found the rebuild instructions as you indicated.
Thanks a million! Ken

[Mike E.]

Re: Rebuilding '62 Master Cylinder

There's no special secret to the snap ring---I figured out how to do it, and I'm just a poor preacher! I've just taken a couple of small, thin-bladed screwdrivers and tapped them in and under and pried out. It's just tedious, but do-able.

[Kennith H.]

Re: Rebuilding '62 Master Cylinder

I noticed the flatened sections of the snap ring, but for some reason I failed to recognize your solution - just stuck on using pliers on the ends - no good.

Thanks Mike,
Ken

[Kennith H.]

Re: Rebuilding '62 Master Cylinder

I previously indicated that I would hone the cylinder in the process of rebuilding the unit, but the instructions do not mention honing. I also found some instructions in an old Chevy manual and they also don't mention honing. I would think it prudent to true up the bore by honing. Wheel cylinders are honed, why not master cylinders? I really don't want to screw this up (an unintended byproduct of some of my projects) so any ideas are really appreciated.
Ken
(Sorry this thread is running on - should have thought of all these things to begin with).

[Jack H.]

Re: Rebuilding '62 Master Cylinder

Yes, visually inspect the bore carefully during your rebuild process! The center section is where brake fluid traditionally 'sits' waiting for cylinder actuation. And, since brake fluid is hygroscopic (absorbs water), that's where you'll tend to see rust/pit which will challenge the integrity of piston seal.

The bore needs to be smooth and uniform which is why virtually everyone sends their MC out to have sleeves installed (regain factory fresh and uniform bore walls). But, if a given MC core is NOT badly pitted, running a hone down the bore to freshen up the original bore can and does get the job done without the need for sleeving! It's a judgement call based on experience and visual inspection...

[Jim T.]

Re: Rebuilding '62 Master Cylinder

Kennith I just finished doing a rebuild of my 70's master cylinder. I had a small area of light rust inside the bore. I searched for a hone that was specifically for a master cylinder from Lisle products and only found Brake Cylinder Hones. The one I got for my 1 1/8 bore was the part Lisle # 10500. This covers 11/16 to 2 1/2 inches and is a two stone hone. It cleaned up the bore and left the bore feeling real smooth. I did notice that the honing stones did leave the cross hatch pattern in the bore but it is smooth. It took very little honing operation to clean the surface rust spot. Hope this brake cylinder hone was not the wrong type of hone to use on a master cylinder.
I used denatured alcohol to clean the cylinder bore and fluid cavities and the outside of the the master cylinder. Painted the master cylinder and will assemble it tomorrow.
One thing I did read in one of my service manual, believe it was the 63 Corvette service manual, do not use any motion except circular motion (rubbing) to clean up the bore.
I will be using DOT 5 silicone brake fluid.