Master Cylinder Restoration

[B5 Charger]

Doing another amateur part restoration that I thought some folks might benefit from.  Bought the master cylinder and booster off Dino's 69 since my master was obviously an aftermarket junker.  We thought they were original to his car but after looking them over I believe they are rebuilds.  Still accurate, or accurate enough for what I need.  Here's a few before photos of the master.

[B5 Charger]

This is for a 4 wheel power drum brake setup.  Here are the numbers from the bottom as best as I can decipher them.

Bendix

5 - Don't know what that means.

X176? - I think this is the date code.  Possibly October 17th 1967, 68 or 69.  Can't make out the last digit so I'm going to pretend it's 1968 cause that's what works for my car.   

2225601 - A body drum brake part number.  My understanding is the A and B body's were interchangeable but had different part #'s.

[B5 Charger]

It took me awhile to find a source for the parts but Raybestos makes a kit that has all the parts needed.  Most parts store kits just give you new preassembled front and rear pistons.  This Raybestos MK474 "Professional Grade" kit has the front and rear pistons as well as the brass outlet port seats and new check valves/springs.  It also comes with other parts that I think fit other master cylinder models.  It even includes screws that you use to remove the old brass seats although I just used an old drywall screw.  I got this kit from Rock Auto but I've seen them on ebay and other websites.  It comes with a decent set of instructions as well.  The first couple pics are the kit and contents the 3rd and 4th are my master cylinder broken down.

The master breaks down fairly easy.  The main steps are 1 - Remove the rear piston retainer and the rear piston comes right out.  2 - Use some compressed air in the front outlet port to force the front piston out (watch out it will go flying if you hit it with too much air pressure).  You may have to remove the front piston retainer bolt first if yours came equipped with one but mine didn't.  3 - Drive a deck or drywall screw into the brass outlet port seats and then use a pair of pliers to pry them out.  Make sure you have new seats before you do this because you are going to ruin the old ones when you remove them.  After the seats are out the old check valves and springs will fall right out and your ready for cleanup.

[birdsandbees]

Thanks for this.. I just picked up a vacuum booster and master cylinder for my 'Bee for $95 bucks. Even though it all looks good I figure I can afford to rebuild it to be certain and now have the kit number!  

Just ordered the last kit available from Amazon.com for $24 bucks delivered c/w import taxes. None available in Canada from Amazon.ca and most others I found are about 50 bucks US + postage. I won't hold my breath until it gets here..

[B5 Charger]

No problem B&B I figured if I was having trouble sorting it out there was likely other guys scratching their heads too.  I would love to have the money to just send this stuff off or to buy it already done but I try and save money where I can so I can stretch my Charger dollars further.  Be sure to keep up on this thread I managed to screw some stuff up and can probably save you from the same fate.   

[Dino]

Uh oh what happened??

Kudos to you for rebuilding it, I would've just painted it as the brakes worked.  It is very interesting to see the insides though.   

[B5 Charger]

Yeah, I planned to rebuild it just to make sure everything was good to go.  I didn't screw up the master cylinder I goobered up the brass seats whilst trying to press them in.  Had to find a source for new seats so I didn't have to buy a whole new $35 rebuild kit.  Pain in the neck but my own fault.   

[B5 Charger]

Next round of pictures.  I cleaned up the body with Brakleen then put the cap on, plugged all the ports and blasted the paint off the outside with glass bead.  Blew it off, removed all the plugs, more Brakleen and then dunked the whole thing in Evapo-Rust for 24 hours.  The bore was in really good condition with only minor pitting in a couple places.  I used a brake hone to clean up the bore, then more Brakleen and she was ready for the check valves/springs and brass seats.  First two pictures show the housing all clean and ready to go.  The third picture shows the  check valves/springs sitting in the outlet ports.

[B5 Charger]

Time for the brass inserts.  The instructions tell you to use an inverted flare nut to press the new brass inserts into the outlet ports until they are seated.  I didn't have the correct flare nuts handy so in my internet video travels I found someone seating them with a nut driver and mallet.  This is the route I decided to go.  Word of warning I WOULD NOT USE THIS METHOD as I seriously screwed up one of my brass inserts.  Having messed up my insert I scoured the internet looking for just a set of brass master cylinder inserts.  The only set I could find was here https://www.musclecarresearch.com/gm-pd-valve-tube-seats-1.  Sure they say they are for a chevy but they looked right and the measurements were all the same.  I ordered a set and when they arrived I was all over them with my calipers to make sure they were the same.  They measure out at the correct height, diameter top and bottom, correct size outlet hole and correct face angle.  I would say they are pretty much identical to the kit inserts from Raybestos.  The first picture is my fouled up brass seat so you can see the potential hazards of trying to drive them in with a nut driver.  The second picture has the new inserts alongside the mangled one.

[Dino]

Yikes that insert really bit it!  I'm glad you found a replacement.  That master looks sweet!   

You know I just remembered I still have some engine bolts in evapo-rust?  I put them in there about 5 weeks ago, think they're clean by now?   

[B5 Charger]

I would hope they're clean by now, rust free at least lol.  I'm waiting for my flare nuts to arrive so I masked off and painted the housing with some Eastwood cast iron brake caliper paint.  I blasted the lid and it had some fairly deep pits.  I don't normally worry too much about stuff like that but since it is right in your face when you open the hood I decided to body work it since it's getting painted.  Nothing special, plastic filler, sand, filler primer, sand, filler primer, etc.  Here's the painted master and the lid ready for paint.

[B5 Charger]

Been awhile since I've been on here but I finished my master cylinder project.  Bought some inverted flare nuts to press the new brass seats in place.  Nothing special just drop in the valve, drop in the seat and press it in by threading in the flare nuts.

[B5 Charger]

Here it is all put back together with the lid painted using the Eastwood gold cad system.  It's more gold than real plating would be but considering it's paint I'm satisfied wit the result.

[resq302]

nice job !  Did you consider sleeving the bore to prevent corrosion in there?  Or was your bore good enough to be cleaned up with a hone?

[B5 Charger]

Thanks!  There was limited corrosion in the bore so I was able to hone it and get it cleaned up.

[Dino]

Excellent work. 

I barely recognize it.  What are the plans for the booster?

[B5 Charger]

Same thing Dino, just have to find the time to get to it...