Topic: Master Cylinder Flare Seat Removal??

[72Grabber]

HOW TO REMOVE MASTER CYLINDER FLARE SEATS?

I've got a '72 with manual drum brakes all around. Original Ford MC, I'm rebuilding this MC and haven't had any issues so far until trying to remove the flare seats. Since this is the original MC to the car (casting date of April 27 for a car built on May 23) I do not want to damage anything. I've never removed flare seats before and need to know if using the sheet metal screw method will damage anything. It looks like there is a metal tube within the flare seat hole, and using a screw will certainly destroy this tube. What is the tube (part of MC or a check valve?) and how much force is needed to remove the seat?

Oddly, this subject is non-existent on the internet or YouTube.

Any help is greatly appreciated!

[rhjanes]

I'm curious why you wish to remove them?  Is one damaged?

[Bob Gaines]

I'm curious why you wish to remove them?  Is one damaged?

+1 ?   Not much on the procedure most likely because it rarely is needed to be done.

[67350#1242]

Sheet metal screw method works very well and is rather simple.  In fact many of the older MC kits contained screws for this purpose.  Basically just screw in until snug, then pull the seat out (pliers, etc).  On some applications, there is a rubber valve and small spring under the seat, which gets replaced before putting in the new seat.  New seat is simply pressed in with the appropriate fitting.
In the picture below the check valves are shown, as well as seats with O rings, and self tapping screws.
 

[72Grabber]

Thanks for this info!!! It answers all the questions I had. What shop manual was this pulled from. I looked through my 1972 factory shop manual set and nothing like this was to be found.

[CharlesTurner]

I had a '68 master cylinder rebuilt and they removed the flare inserts, they came in a baggie with the screws still in them.

[67350#1242]

Thanks for this info!!! It answers all the questions I had. What shop manual was this pulled from. I looked through my 1972 factory shop manual set and nothing like this was to be found.

I found the shop manual picture in my files.  Must have been saved for 10 years or more since that was last time i rebuilt a MC.  I think this info is from earlier than 1967, because my 67 Mustang shop manual does not contain info on replacing the seats, and in fact says not to remove the seats or valves.  They are shown on one exploded part figure but the valves and seats are marked as "not serviced".   
I guess I was just lucky in saving the page.  I do remember changing the valves and seats in the MC for my 67 Shelby and having a hard time back then finding a kit with the parts to do so.
I did a quick internet search and didn't turn up much of anything except for this video of an old guy working on MOPAR MC's
This is pretty entertaining and fun to watch:

Enjoy - Kurt.

[72Grabber]

Ya i've seen a few of that old codgers videos (ha) ... He has a rebuilding service that supposedly does top notch work.

What I've found is that in 1972 (apparently) Ford's MC's had the non-serviceable seats. Thats what I have...  they are definitely DIFFERENT than the earlier ones....  My MC is a C8 casting but a D2 production code- original to my '72 Grabber. I found a great rebuild kit on eBay, NOS Wagner-Lockheed with the seats, springs and valves. It arrived today and there is a note on the small parts envelope stating to discard these replacement parts on 1972 and newer MC's. They are clearly different- the replaceable ones have a large hole- the '72- ones have metal tube in the middle of the brass seats. That's what stumped me when I (briefly) attempted to remove one. I stopped before inflicting any notable damage to the hole. I also have a NOS Motorcraft MC kit on the way, which has the plunger stop "button" which is very hard to find.

This is all very hard-to-find info and should help others at some point if they find themselves in the same situation/questions, etc. NO videos on YT or 'net articles to cover any of this.

pics....

[196667Bob]

The procedure Posted by 67350#1242 is from the Preliniinary Shop Manual.

As for a reason to remove existing seats, see attached picture. Need I say more ?

Bob

[72Grabber]

Thanks Bob!  Yes, that would definitely be an issue.

My question is- is there anything behind that seat that can get clogged up, or seized up? I have yet to find any documentation of what all is behind the seat, and in what order etc. Do the later seats use the same springs and valves? What are the small tubes seen in the center of the later seats?  I plan on doing one final soak in evaporust and then brake cleaner solvent wash to remove all water and rust potential from the MC, but it will be with the seats in place....  not sure I could successfully replace them if there is some unknown item that would crop up unknown to me.

[67350#1242]

I suggest using some kind of blunt poker in the hole to see if you can feel something springy, or if it will just pass through.  The check valves were only used in drum brake circuit.  Disc/drum will only have valve in drum circuit, drum/drum in both.

[72Grabber]

This is manual drums all four corners. (1972)... drill bit goes through cleanly into main bore. Doesnt appear to be anything behind the seats except the passage.

I received the Ford Service kit today (D2 p/n) and it has much smaller seats than the Wagner kit with valves and springs, and contains no valves or springs. The Ford kit seats look to be the same dia. as my MC but I still dont see the "step" looking part on the cone of the seats (what looks like a small tube)...