Installed a new M/C, doesn't work at all, what am I missing??

[AcampoDave]

A poor connection with a tiny leak can cause big problems. Recheck those front connections, wipe them clean and dry then watch for fluid weeping out . That's all I can come up with.

[old cool]

Buck, you never mentioned suspicion of your new MC. I'm going to assume that I'm not telling you anything new, but I've got to add a point or two. To rule out the master cyerrlinder as the problem, I would assume if you had someone push the pedal a few times, then hold it down, and then crack each line (separately) on each side of the master cylinder , you could see if it were pushing the fluid at each nut. If there is no fluid squirting at the nut, your prob is MC. If not MC, then you work your way down to the bleeders, again, having someone to press the pedal several times, then holding it and then cracking the bleeder. If your wheel cylinder (s) are not allowing the fluid to pass through, I would assume prob is malfunctioning at one or both WC. I'm sorry if this sounds insulting. But as you said it is not rocket science. And as the old high school science teacher said, test one variable at a time so you know what corrected the problem.
Looking down into a 67 style dual MC, there is a vent hole and a replenishing hole in each barrel. I dont know how your MC is built, but i would imagine the vent hole must be open for proper circulation. Please dont ask me how I know this.

[Captainfab]

I didn't go back to see if this was mentioned before, but have you checked your proportioning valve to see of the valve has slid across and blocked the ports to the front?

[luvbowties]

x2^^
sam

[64shortbox]

I had the same problem when I installed my Disc Brakes on my truck. I couldn't get my front or rears to bleed out fluid no matter what I did so I made myself an Okie pressure bleeder and it worked great. The bad news is I was able to get everything I need from the scrap pile we have at work. I had to crank the air pressure up to almost 30 LBS though to get enough pressure to bleed everything. I know you have the stock Drum - Drum setup but I thought I would pass along the info & pictures for reference. Hope it helps though.

[AcampoDave]

Sometimes when I can't get the pedal to pump up, I have a helper stab the pedal to the floor when I open the zerk. Then I close it and he releases the pedal. We repeat this and after a few rounds, enough air gets expelled to allow the pedal to pump up.

[padresag]

there is also a bleeding sequence to that style of m/c. left rear(drivers side), right rear, right front and then left front. furthest point from the m/c to the closest at the end. do it all in one operation. don;t do the rears and go and have supper and then come back and do the frts. make sure that you have eliminated the air at any wheel before going on to the next
ron

[buckroseau]

Progress today in the right direction! As I mentioned, decided to replace the M/C since I really didn't have much else left to look at. Ran over to O'reilly's and ordered one up. Nice thing is O'reilly's distribution center is about 35 min. from my house. So, you can buy a part at a store and pick it up right away if you want, even on Sunday.

First thing I did was bench bleed the new one! Should have done that to the other one, but had never had an issue. As soon as that was done I pulled the old one.....and right away I saw the issue. I took a pic and attached it. As you can see the brake cylinder on the M/C got pushed in about 3/4" and wouldn't return. That would explain why this whole time I was pumping and pumping and there was no pedal resistance. I played around with a bit, but it wouldn't return. I had a new one and since there not that expensive I figured I didn't want to mess around anymore. I got the new one installed and as soon as I hit the pedal I had some pressure. I was able to pump it up and hold pedal pressure fairly easily.

I attempted to vacuum bleed the lines but it just didn't work that well. It is pulling air and a little bit of fluid, but not enough. I've got family coming in over xmas so I am going to have my brother in law give me a hand pumping it up and cracking the lines the old fashion way. That's always worked in the past for me and I'm fairly certain that will work in this case.

I appreciate all the help and comments you guys offered up, that was great. I think the moral of the story here is to bench bleed the M/C's prior to installing. I think most already do, but I had never did. Not sure if it would have locked up bench bleeding, but it may have?

One other question semi unrelated to this problem. Do you guys have a copper washer on the front soft lines where the line screws into the front wheel cylinder? I got new lines and they didn't come with them. The guy at the parts counter did not show one on his computer in the parts blow out, so he said they weren't needed. The old ones I took out had them on.

Matt

[Captainfab]

Glad to hear you have found the problem. Yes I would install those copper washers where the hose threads into the wheel cylinder. That makes a positive seal at that connection.

[earl84]

What a saga. Glad you found your issue finally.

[65 C20]

Wondering if you have pulled your master apart and put a kit in it or have a replacement for it ?
Post when all is well.