Master Cylinder replacement, help...

We figgured out in that other thread my master cylinder needs to be replaced since it looks like a swamp of brake fluid and carpet under the driver's side floor mat. Makes my car smell wonderful inside. Gonna have to pull the carpet out and scrub it everything out this weekend I guess.

Well I have a '73 4 door parts car with a master cylinder that is less then a year old and has less then a thousand miles on it. Went to NC this weekend and pulled it out. All I did was take loose the 2 brake lines going in the side and then take the 2 nuts loose from the firewall and it just came right out. I just left the rod there connected to the pedal figureing I can just reuse the rod in my car.

Well today I am trying to get the original master cylinder out of the Grabber. I took loose 2 brake lines on the side with the help of alot of PB Blaster (hadn't been taken loose in 31 years), and then took the 2 nuts off that hold the master cylinder to the firewall. Try to pull out the master cylinder and the rod going into the back of it from the pedal won't come out? I've turned and pulled and twisted it and it will not come out of the back of the master cylinder. The one on my 4 door just came right loose.

Whats the deal?

 

Once the brake rod has been inserted into the Master Cylinder it should lock and be impossible to get out ... although I assume the folks that rebuild these things have some sort of special tool to release it.

When I bought my Master cylinder for my Grabber the rod was already connected which was not good because I wanted to replace it with an adjustable rod. I returned it to Autozone and had them pull a different brand. The second brand came with the rod disconnected so I was good to go. You cannot buy the rods seperate. I think I may have the rod I didn't use laying in the bottom of my tool box at home. I can check if you want later tonight ...

Also ... Power Brake Master cylinders to not have a locking tab inside the M/C ... so more than likely your parts car had a power M/C installed in it if the rod just pulled out. Manual brake cars have M/C's that the rod locks.

 

The parts car had all manual drums just like the Grabber. The new master is slightly diffrent. The top covers will not interchange between the 2. The reservoirs on the new master cylinder are both the same size where as the rear reservoir on the old master cylinder is bigger then the front.

All I know is that 4 door would stop on a dime to be manual drums. It stopped extreamly well and I gotta hunch it has something to do with this master cylinder being diffrent. I believe the previous owner of the 4 door told me the master cylinder is for a 67-70 Mustang...

On another note how do I get the rod loose from the pedal? I can only do it by feel as I can't really see much up in there. I pulled some sort of clip loose but I still can't figgure out exactly how it comes loose.

Thanks

 

Pull the retaining pin out ... slide the brake light switch and rod off the brake pedal ...

 

Got it. If you could dig up that rod I would greatly appreciate it. Wish I would have grabbed the one out of the 4 door now...

Now that my car is nicely disabled and I have to get it going by tomarrow, would it be possible for me to come pick up that rod around 9:30 tonight? (when my mom gets home from work with her car).

If you can find it that is.

Edit: out of curiosity, I wonder what would happen if I removed the little C clip thats around where the rod goes in. Maybe I could just pull the guts of the old master cylinder out and get the rod loose that way? One way or another I gotta have a new master cylinder anyway...

Can anyone make a solid argument as to why I shouldn't just take the old one apart to get the rod out?

 

Well I got the rod out. :bananaman

Pulled the C clip loose and pulled everything out of the master cylinder. Wow, not much in there. The rod was locked into this solid piece of metal with a rubber seal on either end a spring on the end. I locked that piece of metal in a vice and then stuck one side of a claw hammer through the round loop on the end of the rod that hooks onto the brake pedal. I then took an all steel dead blow hammer my dad made years ago and whacked the top of the claw hammer. After about 10 solid whacks the rod came out and flew half way across the garage. Did I ever mention I love working on this car?

Now I'm getting everything put back together. Hopefully it works.

 

make sure the rod stays well clipped in to the new one. really hate for you to hit the brakes to find it had popped out and wasnt engaging the cylinder.....good luck

 

...FYI...the master cylinder with the larger reseroir is for disc brakes,it's most likely it came from a disc brake car....Hotrod-Daddy

 

i didnt even catch that detail, probably why it went out so fast. kinda curious why he would buy a mustang master instead of the correct one. id be curious what else he modded on your car.

 

No, the master cylinder on my car was the original factory one. Never been replaced. The rear reservoir on it is bigger and my car has 4 wheel drums. It didn't "go out fast" at all, I would say it has done pretty good to be 31 years old.

The almost new one that I am replaceing it with is for a 67-70 Mustang and both the reservoirs on it are the same size. The 4 door also had Mustang front drums and hubs on it. I swapped those to my car a while back and they work way better then stock Mav drums. The Mustang master cylinder seemed to really work good on the other Mav also.

Both cars have 4 wheel manual drums.

 

will the stock cylinders be able to handle the mustang pressures? the other car had mustang slaves as i understand it?

 

The stock wheel cylinders will handle it fine. Can't see why they wouldn't. The 4 door had stock wheel cylinders. I honestly don't think or know if Mustang wheel cylinder would fit, but there is no reason to use them anyways. Just had a Mustang master cylinder, front drums and hubs. The Mustang drums have cooling fins on them where as the stock Mav drums are just a solid chunk of steel with no cooling fins. In fact I would reccomend the Mustang front drums to anyone still running drum brakes on their Mav. They work better for longer in stop and go traffic and when they do fade it takes them about a quarter of the time to cool off once you get moving again.

The Mustang master cylinder I am putting on looks identical to this

The drums I have on the front of my Mav look just like the ones on this car They have seperate hubs so I can take the drums off the front of my car without haveing to pull the wheel bearings and everything out like on stock Mav drums. Stock Maverick brake shoes and everything work fine with those drums.

Man I wish my digital camera worked...

 

Ug. BFH work every time.

Ug.

 

Can someone help me out with how the heck the brake light switch goes back on? A picture of your switch installed would be wonderful.

 

My 74 also has a M/C with a larger reservoir for the front brakes even though they are drum. I also got the parts from a 74 disc brake car it it has a proportioning valve and not a distribution block .... I know some have said 74 had a distribution block whether the car was drum or disc ...