looking inside master cylinder '48 Chrysler

[harmony]

I was assured that the brakes were complete gone over on my car before I bought it 2 and a half years ago.  I have a tendency to believe that, because the wheel cylinders look new on the outside and new brake lines and the tin plate on the MC that holds the push rod boot on still sparkles and looks new.  The boot looks new too.   However at least half of the whole system was either clogged or seized.  The only thing I haven't gotten into is the MC.  Like I just said that boot retaining plate is like brand new.  No signs of any rust on the outside of the MC either.  Looking down into the reservoir after I pulled out all the old fluid, looks new.  

But Holy Shmuley, in order to pull the MC off, it looks like I need to pull the trans out.  Ok, maybe that's exaggerating, but there isn't enough room to pull the large dia. pin out that connects the brake and clutch pedals to the MC.  So maybe if I remove the brake and clutch return springs, remove the brake and clutch foot plates ( rubber over plate inside the car)  then pull the 3 bolts that hold the MC to the mounting bracket, then drop the clutch and brake arms through the floor, maybe I can wiggle the whole assembly at enough of an angle to get that large dia. connecting pin out.  Then that would release the MC.  

Has anyone done this?  Am I on the right track?

Or,,,,,  As I said I just want to have a look inside to see if there is any corrosion or rust/moisture.  So what if I disconnect the two new brake lines that I just installed that come out of the back end of the MC.  Then unthread that big brass end cap.  That should let me get a good idea of the inside condition, shouldn't it?

The way it's designed you can't just come in from the push rod end, unless the MC is unbolted and slid at least an inch sideways towards the trans. You need to do that to get at one of the small bolts that hold on the boot retaining plate. There's just no way to get a wrench on it as it is.  Part of the MC mounting plate is right over top of the head of that small bolt.  So anyways you can't slide the assembly sideways because the clutch and brake arms don't have that much lateral movement.  So if there is bad news inside and I need to rebuild the MC, I'm going to have to pull it out of there anyways, 

Unless,,,,,, If I disconnect the forward end of the push rod, then push the end of it towards the transmission carefully and slowly so as not to damage the rubber boot, that might give me enough room to get a wrench on that one small bolt ( 5/16-3/8) that holds that plate that secures the boot.  That will also depend on how long the small bolt is.  If it's 1/4" long, it might slip out, because there is a slight area ( half circle) cut out of that plate that lines up right over that bolt.  It the bolt is 1/2" long I don't think it will come out.  If I can do that there is enough room to pull all the inner parts out and if I've gone that far I might as well just rebuild it if it needs it or not without removing the MC,,,,,, I think. 

 

Sorry for rambling, I guess what I'm really asking is, by taking off that large brass end cap on the end of the MC, will I get a good idea of the inside condition?

Edited December 30, 2021 by harmony

[MarcDeSoto]

One mistake I made on my car concerns the MC from Rock Auto.  They offered $15 core exchange for a replacement rebuilt MC, so I sent the old one to them.  So when I got the new MC, it was missing some major parts.  Namely the push rod, the nut, the end, the pin, and the clip.  These are impossible parts to find and they don't come with a rebuilt MC.  I had to get replacements for these parts from a friend who had a 50 DeSoto parts car!  bottom line, don't send in original parts just to get the core charge.  

[harmony]

I got the MC out today and I think it would have been easier to flip the car on it's roof and get out a set of cutting torches.  It was a struggle all the way and it took 2 hours. The brake and clutch foot pads had to come off that are connected to the brake and clutch arms.  Then I had to unbolt the floor and separate it right where the arms go through the floor and wedge in 1 1/2" blocks of wood to keep the floor sections separated and allow a little wiggle room.  I disconnected lots of linkage down below.  After removing the C clip on the end of that 3/4" pivot pin I still couldn't wiggle out the brake arm off the end of it.  I took the 3 MC mounting bolts off and lifted and lowered and twisted all the parts together and then finally the brake arm slipped off the pivot pin after hammering it to death with a tap hammer and 2 inches of swing room.  Then I thought it would be easy to continue by simply slipping the MC off the pivot pin and I'd have it out.  Not a chance.  The clearance between the eye opening on the MC for that pin and the pin is extremely tight.  So tapping the side of the MC wouldn't budge it along the pivot pin.  Mind you I only had about 2 inches of swing room for my tiny tap hammer.  After about 5 minutes of tugging and twisting and knuckle scraping, the MC, pivot pin and brake arm and one piece of linkage all came out at once,,,, backwards.  It wasn't going forward because the brake arm wouldn't drop down, so I was amazed that it went out backwards between the floor, frame, trans, and cross member.

 

After all that, the MC was in perfect condition inside.  At least I have piece of mind now.  Now I have to try and remember the procedure to get it all back in place.

[Dodgeb4ya]

The master cylinder can be removed from the car without removing the floor board leaving the pedals hanging in the floor board.

I have done the 1946-54 cars that way for a long time. 

A pic showing ready to pull out with pedals and floor board still in car...1946 Chrysler 

Way too long to take the MC out any other way for me.

What's needed is finesse.

I realize probably too hard for most. 

Edited December 31, 2021 by Dodgeb4ya

[MarcDeSoto]

I hear you.  Harmony, boy that was a lot of work just to look inside the MC!  I was doing the same thing today trying to get the overcenter clutch spring installed.  Taking Dodge's advice, I was able to get the overcenter spring installed by turning the turnbuckle out.  Everything was good.  Then we discovered I had put the the turnbuckle rod on the frame side of the clutch pedal shaft!  It was crooked.  So we had to take everything apart again for the tenth time to make it right.  I can't even conceive of how difficult this work would be if I still had the body on!  I sure couldn't do it.  So we put everything back together again and I was pushing the clutch pedal down to see how good it was.  It was very stiff and didn't seem to work very well.  Then I discovered that the overcenter spring wasn't in the hole at the bottom, but just next to it.  So I said to my helper "just give me a hammer and I'll hit it in"!  He said he wanted to get over ten feet away if I was going to do that.  After I hit the spring, I found out why he got away!  The spring snapped loose and exploded and bounced off the ceiling of the garage!  I could have lost a couple of eyes on that one!  I sure would like to have somebody here who does this kind of work all the time!  I'm just guessing at it.  Another problem, we were not able to get those last two bolts in at the back of the clutch pan.  The bolts are 1 3/4" long, but no room to install with the crossmember in the way.  Maybe you have to install the clutch pan before you install the bell housing and transmission?  

Edited December 31, 2021 by MarcDeSoto

[harmony]

19 hours ago, MarcDeSoto said:

I hear you.  Harmony, boy that was a lot of work just to look inside the MC!  I was doing the same thing today trying to get the overcenter clutch spring installed.  Taking Dodge's advice, I was able to get the overcenter spring installed by turning the turnbuckle out.  Everything was good.  Then we discovered I had put the the turnbuckle rod on the frame side of the clutch pedal shaft!  It was crooked.  So we had to take everything apart again for the tenth time to make it right.  I can't even conceive of how difficult this work would be if I still had the body on!  I sure couldn't do it.  So we put everything back together again and I was pushing the clutch pedal down to see how good it was.  It was very stiff and didn't seem to work very well.  Then I discovered that the overcenter spring wasn't in the hole at the bottom, but just next to it.  So I said to my helper "just give me a hammer and I'll hit it in"!  He said he wanted to get over ten feet away if I was going to do that.  After I hit the spring, I found out why he got away!  The spring snapped loose and exploded and bounced off the ceiling of the garage!  I could have lost a couple of eyes on that one!  I sure would like to have somebody here who does this kind of work all the time!  I'm just guessing at it.  Another problem, we were not able to get those last two bolts in at the back of the clutch pan.  The bolts are 1 3/4" long, but no room to install with the crossmember in the way.  Maybe you have to install the clutch pan before you install the bell housing and transmission?  

Wow!  Quite the story.  As I was putting the MC back on the car today, ( with grunts and groans, no finesse required, haha!) I had to apply some tension on that assembly that that monster spring is attached to.  Several times I almost had the linkage slipped on when my screwdriver would slip off the end.  The spring snapping back like a bear trap, and the screwdriver dancing across the floor.  In hind sight I should have gone up a couple more notches on my jack stands to make life a little more comfortable while wrestling with stuff under the car, while on my creeper.  But in the end it's all good stuff and very rewarding. 

[MarcDeSoto]

Yes, if you read my other post about the clutch spring, you will see that DodgeB4u just posted a picture of his overcenter spring show me how it's done.  Hook the bottom part of the spring through the top of the hole, not the bottom of the hole!!!!!!!!  Save your life!