Manual Disc/Drum Headache

[khryslerkid]

Bench bleeding a MC you want to slowly bottom out the piston each stroke until there's no air. Then plug the ports before installing it back on the car.

Bleeding the system you start with the furthest bleeder from the MC first. Right rear then left rear then right front and left front.

If someone is helping you, they need to pump the pedal a few times and then hold pressure on it until you open the bleeded. Then only after you close the bleeder are they to let up on the pedal.

Doing it by yourself, you can use a bottle with some brake fluid in it. Attach a hose to the bleeder and submerge it in the fluid. Make sure it stays submerged and open the bleeder. Slowly pump the pedal and go all the way to the floor with it to clear the line and wheel cylinder or caliper. Then tighten the bleeder. Check you reservoir often. If it gets low and sucks air, you have to start all over again.

Your caliper bleeders are on top and not on the bottom? I've heard of some of these conversions that the caliper bleeder ends up on the bottom and you won't get the air out. You can remove the caliper in this situation and place something in it to take up the missing pads. Then holding it with the bleeder on top bleed the air out.

 

[Fran Blacker]

Bought some EZ bleeders, like'm.

 

[threewood]

I had the same issue with the complete manual disc setup from Cass. MC was bad, Cass sent me a new one. Another issue I saw was the return spring in the master wasn't strong enough to push the pedal all the way back up so I added a return spring so it was uniform on each pedal press/return.

 

[Gyratingyak]

Bench bleeding a MC you want to slowly bottom out the piston each stroke until there's no air. Then plug the ports before installing it back on the car.

Bleeding the system you start with the furthest bleeder from the MC first. Right rear then left rear then right front and left front.

If someone is helping you, they need to pump the pedal a few times and then hold pressure on it until you open the bleeded. Then only after you close the bleeder are they to let up on the pedal.

Doing it by yourself, you can use a bottle with some brake fluid in it. Attach a hose to the bleeder and submerge it in the fluid. Make sure it stays submerged and open the bleeder. Slowly pump the pedal and go all the way to the floor with it to clear the line and wheel cylinder or caliper. Then tighten the bleeder. Check you reservoir often. If it gets low and sucks air, you have to start all over again.

Your caliper bleeders are on top and not on the bottom? I've heard of some of these conversions that the caliper bleeder ends up on the bottom and you won't get the air out. You can remove the caliper in this situation and place something in it to take up the missing pads. Then holding it with the bleeder on top bleed the air out.

Bleeders are on top. I have bled it in every sequence you listed. Its why I’m at such a loss.

 

[Gyratingyak]

Simple test.... Foot off the brake pedal for a few minutes..... It this point by your description normally the pedal would be low correct?.... Try this, Set the parking brake, then apply the brakes... Now foot off the brake pedal for a few minutes....How is the pedal?

If it sits unused after a bleeding cycle it has a full pedal. If I take it for a drive and it sits the pedal sinks then comes back up, you can then feel the air

 

[threewood]

If it sits unused after a bleeding cycle it has a full pedal. If I take it for a drive and it sits the pedal sinks then comes back up, you can then feel the air

Mine was weird like that too. I could not touch it for 2 weeks and have a firm pedal. Drive it, park for 6 hours and soft pedal. Couple of pumps and it was good again. Go around and check each double flare fitting. Call Cass. A new MC fixed mine.

 

[khryslerkid]

Are you loosing any fluid? If so and you don't see anything, check the boot on the back of the master cylinder.

It sounds like an internal bypass with the master cylinder.

 

[Gyratingyak]

Are you loosing any fluid? If so and you don't see anything, check the boot on the back of the master cylinder.

It sounds like an internal bypass with the master cylinder.

I don't believe I am losing any fluid. This coming weekend is a bust for wrenching. The week after I'm going to crawl back under and go through the entire systems flares. Buying an extra coil of 3/16 line just to be safe if I have to redo a line for make a union. Hopefully its not another master cylinder, Cass did right by me once and I don't want to come off as a leech. I do have a Right Stuff 15/16 bore cast iron MC. I can try it. There original one was bypassing and they sent me one to recoup my losses because they didn't get back to me quickly so I had ordered Cass'. Good thing I horde my car parts haha.

 

[1 Wild R/T]

I don't believe I am losing any fluid. This coming weekend is a bust for wrenching. The week after I'm going to crawl back under and go through the entire systems flares. Buying an extra coil of 3/16 line just to be safe if I have to redo a line for make a union. Hopefully its not another master cylinder, Cass did right by me once and I don't want to come off as a leech. I do have a Right Stuff 15/16 bore cast iron MC. I can try it. There original one was bypassing and they sent me one to recoup my losses because they didn't get back to me quickly so I had ordered Cass'. Good thing I horde my car parts haha.

If the M/C is bypassing internally typically it will hold a solid pedal if you are pressing firmly but will bypass when you press lightly and the pedal will slowly sink...

 

[71charger_fan]

I had a similar problem with my '55 Plymouth. I finally bought a V-5 pressure bleeder, clamped off the rubber line going to the rear axle, and pushed fluid through the rear axle brake line from one wheel cylinder to the other. Eventually, a stubborn air bubble that resisted all previous efforts to bleed finally popped out. I pushed from passenger side to driver side with the driver side jacked up and got nothing. Then I pushed from driver side to passenger side with passenger side jacked up and that bubble finally came out. Overall, I went through more than 8 quarts of brake fluid.

 

[dsd1967]

I was just thinking about this and why I've seen so many threads on manual disc/drum setups, and why mopar only seemed to offer power disc/drum setups. Then it struck me....last fall I bought a 1983 d150 as a temp driver while I rebuilt my 2005 ram hemi. This truck had factory manual disc/drums. I remember driving it for a week or so and noticing more than normal pedal effort (thinking it was power brakes), but the thing was smooth as silk and had no problem bringing the truck down in speed. One day I popped the hood and looked over to see a manual brake system and thought to myself.....well there's your reason.

That being said, that system would be an interesting one to mimic....or pilfer for one of our B bodies. The truck was in way too nice of condition to do any parting. I did absolutely nothing to it for the 4 months I owned it and sold it to a friend the day that I got my ram running for the same price I paid for it. He has made that his little classic car and done it quite a bit of justice....I just didn't need another project or mouth to feed gas and insurance to.

 

[biomedtechguy]

factory manual disc/drums. I remember driving it for a week or so and noticing more than normal pedal effort (thinking it was power brakes), but the thing was smooth as silk and had no problem bringing the truck down in speed.

I certainly could convert to power brakes as part of the multitude of changes I'm about to make on my Roadrunner.
The thing is that I prefer manual brakes!
Much better control and feel to modulate braking power to the point of highest rolling resistance before lockup. The only way I would do something different would be to convert to antilock brakes, and there is way too much that I want to do that costs money I don't have yet to pursue that.

 

[MCODECUDA]

73 to 75 a-bodies had manual disc/drum brakes and that’s what I always go with.

 

[Gyratingyak]

I'm ordering another coil of brake line just in case I have a bad flare. I'm going to check each flare in the system and swap the proportioning valve with another one and then re-bleed the MC. If that doesn't solve it I'm going to Swap an unused 15/16 cast iron MC in after bleeding and test it. We'll see, but I'm about to lose my brain haha. I want to be able to start my engine build already. Suspension is done, just gotta get past this brake hurdle.

 

[biomedtechguy]

just in case I have a bad flare. I'm going to check each flare

You have to stay on top of your flare...

 

[Gyratingyak]

You have to stay on top of your flare...

 

[Dan64]

I'm not familiar with a 71' proportioning valve , does it have a " slide" to it blocking off the front or back systems in case of a leak?. I had this problem with an ot 35' rod I was doing and until the valve was reset to the middle there was no way to bleed the rear system properly.

 

[Ceedawg]

73 to 75 a-bodies had manual disc/drum brakes and that’s what I always go with.

My 70 Duster had manual disc-drum, /6 auto, ac

 

[Ceedawg]

I'm ordering another coil of brake line just in case I have a bad flare. I'm going to check each flare in the system and swap the proportioning valve with another one and then re-bleed the MC. If that doesn't solve it I'm going to Swap an unused 15/16 cast iron MC in after bleeding and test it. We'll see, but I'm about to lose my brain haha. I want to be able to start my engine build already. Suspension is done, just gotta get past this brake hurdle.

Why? If it’s not leaking. Atmospheric pressure or 1500psi, witch one do you think will leak more? Here’s another idea, under pressure the shoes move out to the drums so maybe the shoes are sticking then move back after a day or so. Adjust the shoes tight to drums so they can’t turn then back off a little. Use some dry lubricant on the edge touching backing plate and make sure springs are right and strong. Where are your residual valves for the drums? MC or in line? They could be bleeding down over time too, that’s their purpose, (10 psi) to hold the shoes against the drum, forever. If they bleed down, there’s your pedal dropping

 

[dcala84141]

So what was the final outcome?
Was thinking of during the same disc/drum manual
Conversion to my 68 RR