Anyone know how to rebuild 61 Pontiac Catalina Brake Master Cylinder?

I took the master cylinder apart about 2 months ago and bought the rebuild kit from Rock Auto parts. The new parts came with no picture diagram on correct order of seals. I put it back together as best I could and hooked it up but doesn't seem to be pushing brake fluid thru the lines when trying to bleed brakes using the 2 man method. I think I may have gotten something backwards when I put it together. Anyone have any pics or can describe exactly what goes where much appreciate.

Wizard

 

I just recently rebuilt mine from a 57 Cadillac. I don't know if it is similar but hopefully this helps. It is a single master and if you look into the cylinder from the outgoing brake line (in other words brake fluid would flow towards you) you will see the rubber cup and you would be looking into the cup. On the other side of that is a copper or br*** washer and then there is the metal piston. My piston has a rubber seal on one end, this end with the rubber seal would be installed so that it is not against the rubber cup that I described above. Am I making sense? Working from the opposite direction of the flow of brake fluid, after the piston (rubber seal end) comes the spring and then the push rod with the retaining washer and "C" clip. Hope this didn't confuse you.

 

you will see the rubber cup and you would be looking into the cup. On the other side of that is a copper or br*** washer.

I am with you on this up to about here. I also have a single master cylinder. It sounds very similar to mine but little lost when you are talking about the piston. Do you mean the piston that is attached to the brake vacuum brake booster?

Wizard

 

The piston is what pushes that cup within the cylinder. My brake booster is a completely seperate unit mounted under the hood whereas my master cylinder is located on the frame. Anyway I believe the piston is aluminum and as I stated it has a rubber seal on one end that is the same diameter as the cylinder bore. Looking at the other end of the piston (i'm guessing its about 2-3 inches long) it is simply machined metal surface slightly smaller than the cylinder bore and this end pushes the rubber cup. If you need pics I could probably post tonight. Have you honed out the cylinder and is it free of any pitting? If you look at the brake fluid resevior, check to make sure the fluid is getting into the master cyinder. My master had 2holes one about the size of a brake line the other very very tiny alomst like a vent hole I couldn't even find a tool small enough to get in there so I used a small strand of copper wire to make sure it was clear. I would remove the master and bench bleed it. There is a decent video of this on youtube if you search "rebuild master brake cylinder"

 

The piston is about 2-3 inches long it is made of aluminum and one end will push the rubber cup the other end has the rubber seal on it. Have you honed out the cylinder to make sure it is free of any pitting? Check the holes in the reservior to make sure the brake fluid is getting in there, better yet bench bleed the master. There is a decent video of this on you tube if you do a proper search. My brake booster is a seperate unit mounted under the hood while my master is located under the car on the frame.

 

The piston is what pushes that cup within the cylinder. My brake booster is a completely seperate unit mounted under the hood whereas my master cylinder is located on the frame. Anyway I believe the piston is aluminum and as I stated it has a rubber seal on one end that is the same diameter as the cylinder bore. Looking at the other end of the piston (i'm guessing its about 2-3 inches long) it is simply machined metal surface slightly smaller than the cylinder bore and this end pushes the rubber cup. If you need pics I could probably post tonight. Have you honed out the cylinder and is it free of any pitting? If you look at the brake fluid resevior, check to make sure the fluid is getting into the master cyinder. My master had 2holes one about the size of a brake line the other very very tiny alomst like a vent hole I couldn't even find a tool small enough to get in there so I used a small strand of copper wire to make sure it was clear. I would remove the master and bench bleed it. There is a decent video of this on youtube if you search "rebuild master brake cylinder"

 

sorry for the multiple posts im a fng

 

I think we have somewhat similar master cylinders but slightly different in way they are set up. I will go on you tube to try and find something on how to rebuild single master cylinders.

Thanks,

wizard

 

Could not find anything on You Tube. They only had modern dual master cylinders on there.

Wizard

 

did you bench bleed the master cylinder after you rebuilt it?

 

Spring first,cup second,sealing edge forward,piston 3rd .plunger recess to the rear. Should be a snap ring to hold everything together. Bench bleed by filling with fluid,mount in a vice with as much of the flange as possible,port side accessable. push piston all the way down,catching and saving the fluid. cover the port with a finger and release pressure on piston.Repeat steps untill fluid is air free. Remount on car and bleed as necessary. Good luck

 

The picture from CTFuzz is pretty darn close to what I have but that part after the cup seal that the spring is going into is that part of the brake booster piston or does all those parts fit into the master cylinder? Mine looks like everything from the spring to the solid plunger. I think I may have it in right order but put in backwards from just looking at that picture. Mine mounts on the power brake booster though. The picture looks like a side mount onto a frame.

Wizard

 

Same princible rod is inside booster .........Picture is correct ..........

 

Don't worry about the outside, the inside workings of almost all single unit master cylinders are pretty close to what you see in the drawing that CTfuzz scanned and posted.

 

Ok, picture represents basically the way all single cyl are made I know what I did wrong. I have everything in order but put in backwards. Will flip everything around 180 degrees and see what happens.

Thanks,

Wizard

 

Even after turning all the parts around right,bench bleed the master before installing.Hopefuly you haven"t already damaged your parts.

 

when u dis***emble something lay the parts out in the order that they came out in. these are really simple i just disconnect the cylinder from the firewall do not disconnect the lines lay a 2 x4 from the inner fender to the cylinder head this is your work table, rebuild ,remount no need to bleed.

 

Is it a Bendix or a Delco-Moraine booster? They used both styles in 1961. Let me know which one and I can scan the appropriate pages from the 1961 factory shop manual.

 

Here's one for '59 Pontiac. My '56 Star Chief is the same inside....yours probably will be too.

http://pontiacsafari.com/MPC/Pages/page_0300.jpg

 

Okay, I used the picture that flypa38 posted. This is exactly the same set up that I have. I will reinstall the parts in correct order and see how it works. Thanks for info and pics. Not sure what the manufacture of the brake booster is. I did have it rebuilt though and seems to work fine.

Wizard