I hope someone can point me in the right direction?

-
1

1972Dart

Well-Known Member
Joined
Aug 1, 2005
Messages
165
Reaction score
0
Man have I been reading all the previous posts about swapping front drums to disks. This weekend I did this swap so here's my platform. I have a 72 dart swinger, I changed upper control arms from a 73 disk car along with the spindles. I got a rebuilt master cylinder from the Advanced and new calipers. I retained the original drum brake distribution block and did not put in a proportioning valve as of yet. Everything is hooked up with the bleeders on top of the calipers. I bled the brakes and fluid comes out of all of them but no air! The fluid is steady but not a large stream like I'm used to. The pedal goes to the floor. After pumping several (like 6) times you get some pressure but then to the floor again. I have bled over and over thinking trapped air but I sit here now admitting defeat. :salut: After reading previous posts I see a few peeps here have had bad master cylinders. I did not bench check the master cylinder first but since I pumped the crap out of them for so long this should have taken care of this anyway. So 2 Questions.
1. Should I assume a bad master cylinder and take it back or am I missing
something?
2. Do I have to install a proportioning valve and replace the original
distribution box? I would rather fix this problem and get the brakes
working then install the proportioning valve when I put my line loc on in a
few weeks while doing all the line bending etc.
Thanks for any and all advice you may have, trust me I am in need of some help on this as it may hold me up from starting the paint job this weekend if I can't move the car.
Adam
 
you can bleed the master cyl on the car through the lines , you didnt mention the rear brakes. check the adjusment on them, and bleed every thing from the farthest point first, except for the master cyl ,that gets bled first, make sure the master is for dick brakes, they are different, it should work temporarly with out the prop valve ,i think...some one else may know for sure as i have never tried it....make sure you didnt trip the switch for the brake light on the dash, if you did it wont bleed properly untill you reset the switch....hope this helps...good luck
 
Please explain the comment about tripping a switch for the dash brake light. Since installing all the dash components and instrument cluster, my son's '74 Dart Sport's dash brake light stays on constantly.

Jerry
 
In the distribution block or proportioning valve there is a pressure switch that is installed between the front and rear systems. During bleeding the side being bled will be at a lower pressure which this switch sees as a leak and trips the light. Once the system is bled and the pressures equalize the light should go off.

Quick check to see if it's the pressure switch is to remove the wire from the connector on the block, if the light goes out then there is an issue in the block. If not then the parking brake switch or a short may be keeping the light on.

Regarding bleeding the master cylinder on the car; You can't effectively do it by trying to push all the air in the lines & MC out through the wheel bleeders IMHO. I would disconnect the lines at the MC and run short pieces (usually come with the MC) of line from the ports back into the reservoir and bleed the MC seperately.
 
The rubber hoses from the frame to the calipers will need to be changed. The steel lines do not need to be changed but it's likely some will be rusted and will break during the R&R. It's not a bad idea to replace all the steel lines if they are original to the car just for safety sake.
 
68gts340
first off Thank you for replying. I originally did not bleed the master cylinder I just started on the right rear then left rear then front right and then front left and tried bleeding them. Got fluid but no air out of all of them including the rears. After a long time of trying this and no air still not coming out I then tried bleeding the master cylinder by just cracking the lines one at a time. My cylinder didn't come with any line to connect them together to bleed? I then tried rebleeding through the ports and had the same results, got some fluid but no air and still have no pedal. I'm thinking its a bad master cylinder but I won't get a chance to troubleshoot farther until this weekend. And yes this is a disk brake master cylinder with the larger rear bowl. I plan to cut my old lines from the other master cylinder and hook them up and run them back to the reservoir to try this way to bleed it. I just don't understand why I have some fluid but no air if its allowing fluid to push through why not with more pressure? thanks for the help... P.S I'm planning on painting it Vitamin C orange anyone have pics of a 70-72 dart swinger in this color?
 
I'll give the bench bleed a try Friday night. Could you give me some directions on doing this and what I'll need to do it? thanX
 
just use your old lines like you said.(I plan to cut my old lines from the other master cylinder and hook them up and run them back to the reservoir to try this way to bleed it) thats bench bleeding, only that you will be doing this in the car. just make sure you dont slam the pedle down as this will make a big mess. you can also try to let it gravity bleed as a last reort. just open up all the bleeders and make sure you dont let the resivoir go empty. if I can get some pictures of my car I will post them for you thats the color of mine 1970
 
ok 72 does the flow of the fluid seem to be correct? or is it just trickling out ? (either front or rear)..if it is just a trickle on only one end (frt or rear) then i would suspect t the switch ... if this seems like it may be the problem let me know and i will try and explain recentering the switch...Ron
 
dodge-n-it, if you could pm some pics or post here that would be great. I've seen vit c on other mopars just not this era for some reason and the web pic I have found looks like another orange color but not what I was thinking.

68gts, the fluid seemed to just trickle out, it was a steady but smallish stream on all 4's. I want to say the rears had slightly less than the fronts but either way its not like what I'm used to at all and there was absolutely no air. I won't be able to work on it until Friday so I won't know more till then. Kinda sucks but I expected a few hitches on this. My upper control arms have a slight difference in angle compared to stock drum ones so even after marking the old alignment, the alignment on the new set up is still way off. I wanted to get all the mechanicals done before paint and this was the last one so I thought I'd knock it out. Guess the mopar gods have something else in mind for me as usual?
 
72.. ok lets go back to basics and check on the rear brakes.. make sure the parking brake is all the way off, verify this by pulling off the drums, with the shoes centered the tops of the shoes have to be fully returned to the anchor ( thats the round stud at the top ) if they are not then back off the parking brake cable so they rest on the anchor. be sure to adjust up the brakes afterwards, next( if the front hoses are old ) disconect the steel lines before the rubber flex hose and check for fluid flow at the steel line, i have seen restricted flex hoses in the past. next we need to know if the dash board brake light is on. also verify that it is working. if the switch has triggered (light on ) then we have to reset the switch in order to bleed the system. let me know and i will walk you through that if need be . one more question ...what are the chances that anything other than dot 3 brake fluid has ever been put into your brake system ? .. I know some of this is pretty basic but we all over look the simple things ....i had a guy once that used ATF for brake fluid and it ruined every rubber part in the brake system..... also the front end will settle down some after driving around a little bit.... this may help with the camber being off on those front wheels if that doesnt work i can tell you how to do a backyard wheel alignment with out any fancy tools. it will be close enough to get it to a real alignment place without scrubbing off the tires.
 
[QUOTE='74 Sport]Please explain the comment about tripping a switch for the dash brake light. Since installing all the dash components and instrument cluster, my son's '74 Dart Sport's dash brake light stays on constantly.

Jerry[/QUOTE]

Jerry just wondering how you made out with your brake light on problem
 
1972Dart: I switched to a disc setup on my '65 Barracuda last winter, had similar problems to you. I did not bleed the master cylinder first. We tried to bleed it through the lines, but like someone explained, that won't work. We eventually had to disconnect the lines from the master, run short lines up from the connectors into the bowl, and bleed it properly. After that everything seemed to work...BUT I have a leaky seat on one of the connectors. I've taken it apart and redone it a few times, so now I'm convinced the seat or something is defective and I'm going to replace the master cylinder. It was a rebuilt from Cardone. I will use another Cardone one, just bad luck I think. I also bought brand new line fittings that I will use instead of the old ones that may have scored the seat.

On my car, there is no pressure switch in the junction block, that didn't come until 1967 I think. It's just a junction block. I installed a Wilwood/Mopar Performance adjustable proportioning valve in the rear line to adjust pressure to the rear drum brakes. I mounted it under the drivers seat (outside, under the floor) because it was a good place and now I can open my door, reach under and make adjustments. Oh ya, I used small bolt kelsey hayes discs because I have a Formula S sway bar up front and the later style large bolt discs will hit the sway bar.
 
Well NO LUCK. I got down here to work on my car late Friday night and my father in law had already taken the new rebuilt Master cylinder back and got another one. He tried traditional bleeding and still no pedal. So I told him about bench bleeding the way explained here (disconnect from mc and run short lines back into the bowls and then bleed like normal). He seemed to doubt this would do anything compared to cracking the lines like he had done but I did it and still no pedal. I took off the old drum brake distribution block and replaced it with a 73 disk brake proportioning block from my parts car (the only thing I had not done on the upgrade). Still no pedal. So after lots of frustration we finished making the exhaust and then the Fed Ex guy dropped off my hood scoop! So this kept me from cutting my wrists. I re-read the directions from the earlier posts about the brake light being on in the dash from the switch in the distribution block. I changed this part and guess I assumed wrong that this would fix it. So I plan to hook up the battery and check for the brake light and then see if it is on.
Could someone please explain to me how to reset the switch if its tripped ? I only have one more day TODAY to get this fixed so any help or suggestions are greatly appreciated.
ThanX
 
Not sure how rebuilt masters are in the U.S. but in Canada 2 out of fiive rebuilds are faulty. I changed my 70 Duster from drum to disc. Front brake hoses were the same from drum to disc. Used a pro valve from a 73 and I had the same prob. After three masters....ta da!!!
 
You must log in or register to reply here.
-

Back
Top