My 63 had the same MC that is shown in Frankie's photo. In probably one of the most Bubba moves I have ever encountered, and my car is loaded with them, someone filled the bleeder port with soft solder! I called all over for a jobber replacement unit and although everyone had a power brake MC, no one listed a STD MC. So I bought a correct style repo.

 

On my original '63 M/C (oh yes, I have one of these pricey beasts with a new lid to go on it) I don't see a plug. On the '64 M/C it looks like a big plug in the front of the cylinder in the pic above....I'm not near my car so can't confirm right now.

 

So the one with the clip top shown above is a 64 style? My old one looks just like it. When it was installed the line was attached to the front port and a plug was in the side. I had to reroute back to the side for the original style.

 

Yes - '63 is thumbscrew; '64 is the wire bail..

 

And the 64 is probably stocked at all the parts stores. I would have thought they would know to cross-reference to a 64 when I asked for a 63. Oh well, I have one correct part on my car.

 

This vette seems to fight me at every turn. Probably trying to tell me to just do a full frame off restoration and be done with it.

Trying to remove the front passenger brake hose and according to the shop manual, says to remove the double flare nut, then the u clip and then pull the brake hose out. Easy enough, grab my 3/8 flare/line wrench and try to turn the flare nut (counter-clockwise), nope , not budging. Put a little more muscle into it, and yep, it starts to round/strip. GREAT!!!!

It didn't really move much, so what are my options here??

1. Leave as is and worry about changing the hose at a later time?
2. Take some needle nose vise grips and try to turn it?
3. ???

I was hoping to change the hose, since I'm doing a full drums/shoes/springs change. But I think if I proceed and try to remove that flare nut, I could do some damage and the whole steel line to that front right wheel from the line splitter near the MC will have to be replaced, which doesn't look fun considering it's routing under the fan shroud.

 

I had that issue on my '61. That's what vice grips are for once the nut is rounded. It was more important that I have safe brakes than the original part stayed pristine when serviceable repro parts are around.

 

Yeah, the hose is definitely older and would be nice to have new on there. So using vice grips on the flare nut won't compress it or damage the function of sealing that connection?

Am I right in that the flare nut (to remove) should be turned counter-clockwise? Most likely yes, but thought I would ask.

Should I take the 5/8 open wrench and hold the brake hose nut under the bracket while I try to turn the flare nut?

Any sense in using something like WD 40 on it and let it sit for a day to try and loosen the bond?

 

My experience is the flare on the end of the line corrodes to the mating end of the nut. When you try to turn the fitting (counterclockwise) it grabs the flare on the line and tries to twist the line. Same thing happens at the wheels cylinders.

When that happens, I get out the flame wrench and heat the flare fitting until it's red then put the flare wrench of the nut and easily back it off.

WD 40 is not a penetrating oil. Automatic transmission fluid, Marvel Mystery oil, diesel fuel are good. Or buy a commercial brand of penetrating oil. Some are good, some aren't.

 

I have had good results with PB Blaster. Need to soak 24 hrs though.

 

I guess I try some PB Blaster, not sure how I feel comfortable using a flame on it.

And wouldn't you know it, I finally get around to opening the box of shoes and they gave my 3 longs and a short...

For those with the replacement MC's, how did you bench bleed them? The Raybestos unit I have, has 3 outlets and a bleeder valve (like the unit in FTF's pic in post 19). I'm guessing that bleeder valve is for bench bleeding the MC, but the instructions make no mention of it.

My thought process is to...

Attach some clear plastic tubing from the bleeder valve, close off the open port (the other two ports came plugged), fill the MC till about 1/4 from the top, put the end of the tubing into the reservoir and submerge into brake fluid, open the bleeder valve and activate the piston with a philips head screwdriver until there are no air pockets and resistance is felt.

Close the bleeder valve, install MC in firewall, remove cap from main out (some fluid will drip out, but as long as reservoir remains somewhat full, no air should be introduced, and hook up hard brake line.

Does that sound feasible?

Or do I need to leave the bleed valve alone and hook the tubing into the main outlet and bench bleed that way?

 

I thought I heard on a single original MC you bleed at the wheels, no need to bleed the MC since it is not a sealed unit. When the pedal is depressed the MC is activated and the lines become a seperate pressurized system from the reservoir. Only power brake cars had the bleeder at the MC; for service considerations? Here was a thread I had started that discusses the bleeder screw...

http://forums.corvetteforum.com/c1-a...der-screw.html

Hope this helps.

Freddie

 

I would bench bleed. In your local parts store there will be a HELP board or something similar. It will have a Master Cylinder Bleed Kit, A choice of fittings and a plastic tube and a clamp. Put your master in a vise , select the proper fitting and screw into the outlet port. Attach the plastic hose and clamp and route into the master cylinder reservoir. Fill the reservoir and push the piston with a dowel, keep excorcising and you will see bubbles at first then a steady stream of fluid. Good to Go. IMHO do not use the bleed screw.
Keep us informed.
Rene

 

Okay, finally got around to bench bleeding the MC. Purchased the universal bench bleed kit from the FLAPS. Proceeded to exercise the piston until I could only really push it 1/8 inch if not less. Installed it on the firewall, secured the steel line and topped off to within a 1/4 inch of the top.

So here's my new dilemma. I was going to just gravity bleed the brakes, since it's only me and right now I don't think 2 people would do any good.

See when I was replacing the front brakes, I disconnected the front right brake line and basically left it hanging while brake fluid dripped out and the old MC emptied. And really the brake line was dangling for days until I had time to get to it. So I think all the steel lines may have emptied. When I opened the bleeder on the right rear cylinder, nothing came out. And nothing is coming out. The MC is full and I've just left the bleed screw open.

Will the fluid eventually make its way back to the right rear bleed screw?

What are my options here if the whole system is empty, except for the MC?

Do I have to get one of those one handed pressure bleeders now to basically pull the brake fluid from the MC?

Would the 2 person job work (one person pumping, while I operate the bleeder screw, open on the way down, close before pedal goes all the way down, pedal back up, open bleed screw, pedal down, etc.)?

I don't think gravity is going to work in this case, is it?

 

If the piston is all the way back in in your MC and you have free play clearance on the pushrod, it should work okay.

I'd start with the left front wheel just to get things going quicker. Don't get in a hurry.

 

Gravity has never worked for me, but I may just be too impatient; I always used the 2-person pump-and-hold method until the Motive Products power bleeder became available (my wife was glad I bought the power bleeder)

MikeM likes the gravity method - he may have some tips for you.

 

Since you mentioned it. If you can't get fluid flowing, loosen the line just below the MC and let it gravity bleed out. That'll put a little fluid tension on the system and start it bleeding.

 

I just can't catch a brake (no pun intended, well ok, maybe). I was able to have a buddy help me and he worked the pedal, as I worked the bleeder screw.

Starting in the right rear, the procedure was, open bleeder valve, pedal down, close bleeder valve before pedal bottoms out, release pedal, and repeat.

At first it was working, older/murky brownish fluid started coming out with some air bubbles here and there. I was able to get about 2 or 3 tablespoons out and then nothing was more was coming out. It would move maybe a mm and then nothing again. We did the pedal thing for about 50-75 reps and still nothing.

I'm now wondering if the MC is bad or something happened in the internal working of it. When I took the cap off to check the level, the fluid was murky (blackish murky, not brownish). I would have thought it should remain clear (new MC and new brake fluid) and I would just top off as it got low from bleeding.

But after trying to bleed for a while, the level never got lower and I noticed when you depressed the pedal, the fluid would kind of bubble up. Shouldn't the piston force the fluid into the steel line and not up into the reservoir?

I think it's time for the Motive PB, so I'll be putting in an order tomorrow.

 

It's hard to tell if you and yer buddy were doing it right. You gotta' pump the pedal with the bleeder screw CLOSED. Hold the brake pedal DOWN and open the bleeder momentarily and then close it. Do this several times and then go to the next wheel. After you've gone around twice with this method, you should start getting some good pedal. If you don't, either your master cylinder is bad OR your MC doesn't have any free play and is not coming back to home to expose the hole in the bottom of the cylinder that fills the piston. Someone here will have a picture of this.

 

Hmmm, you bring up a good point Mike, maybe I was manually bleeding them incorrect. In the 2 person bleeding process that we did, we never "pumped" the pedal and then while the person in the driver seat held the brake down, opened the bleeder valve. Basically it was me saying to push down on the pedal, open the bleeder valve, close before the pedal before it reached the floor, release pedal and repeat....no pumping, just one push down while bleeder was open and then release.

Well I guess that will all be a mute point now, since I put in my order this morning for the Motive Power Bleeder....

Question for those that use the Motive Power Bleeder...is it necessary to still bench bleed a MC since you are now forcing, by pressure, brake fluid into the system through the MC? Wouldn't the pressure fill all the voids and push any air out through the bleeders?