Dr Diff front disc conversion 68 Road Runner

[rrTor-Red]

Throttle back here grasshopper, it will be fine...lol. We've all been there and done things we regret but it's people and forums like this that is a god send.

 

[Thunderlugs]

Nice to hear from you, Mopar and Missiles. Have not seen you around for awhile.

Was not a productive night. I took the master cylinder off twice. Finally got frustrated and took the master cylinder into the yard and tried to shoot fluid. The front does not move fluid (reservoir for the rear brake), or just trickles very little. The rear reservoir streams, but not like the old master cylinder. I took the old master cylinder and shot fluid across the back yard from both reservoirs.

So, to make matters even worse, I ruined the master cylinder last night on the THIRD install. Not sure how I did this as I finger tight the line nuts almost half way in, but two threads half way in are stripped. It's as if I took a dremel and precisely removed two threads. If I try to tighten past this I get way too much resistance and I don't want to ruin my new lines.

Trying to buy another master cylinder from Dr Diff as he is the only source for the 15/16.

On another note; I can't get the rod out of the new master cylinder. The master cylinder is in my bench vise, and I almost pulled the workbench over trying to get the rod out. When I removed the rod from the old master cylinder it just popped out.

Trying to calm my frustrations, but I'm now questioning my abilities to maintain the mopar hobby.

If I may ask Billccm,.. Is this the aluminum/plastic reservoir 15/16 master that Dr Diff has specially made for him? I just recently purchased the same set up from him. Unfortunately I am some distance away from completing and bleeding my brakes. Wondering if I could experience the same problem. Hoping you find resolution to your problem. Keep us informed.

 

[Billccm]

You may ask me anything!

Yes, this is the plastic and aluminum 15/16 that is a Dr Diff speciality.

Got the actuator rod out thanks to someone over at A Body Only. Took the saddle off the floor jack, used a long extension in the rod hole, and slowly pumped the jack to extract.

At least I had one success this weekend.

 

[rrTor-Red]

This is the one I got from Cass, not the plastic one.

 

[Billccm]

I will say one thing about Dr Diff-he wants to stand behind what he sells. I offered to pay for another master cylinder and he said no. I offered to pay for shipping and he said no. I admitted that I probably ruined/damaged this master cylinder, and he said 'just don't worry about it'.

Dr Diff is outstanding!

 

[Thunderlugs]

You may ask me anything!

Yes, this is the plastic and aluminum 15/16 that is a Dr Diff speciality.

Got the actuator rod out thanks to someone over at A Body Only. Took the saddle off the floor jack, used a long extension in the rod hole, and slowly pumped the jack to extract.

At least I had one success this weekend.

Don't Beat yourself up! The fact that you Have the abilities and talent to do what we do is a Compete success...... that most people Envy!! Hang in there. Thanks for informing all of us!!

 

[Billccm]

So, many many people recommend gravity bleed. My local brake shop manager recommends gravity bleed. I used gravity bleed before and had good results, but I have never bleed a brand new brake system.

New lines, new wheel cylinders, new calipers, so a completely DRY system.

Thinking out loud, I bench bleed the master cylinder. It has no air, and the goal is to never let it run dry. Got it, and to fill the completely dry system you need to continue the reservoirs full. But in my case last night (and I did this twice), fluid never started to enter the system.

This brings me back to needing some sort of helper in the system. Either a vacuum pump, or a reverse bleeder (see this link http://www.forbbodiesonly.com/mopar...-these-for-brake-bleed.130778/#post-910674450).

I don't want to play musical master cylinder swap on my next attempt. Should I try a reverse bleeder?

 

[rrTor-Red]

I would say there's a blockage then. If M/C is bled, no air, put it on. Take bleeders off and install lines. ALWAYS keep eye on M/C. It SHOULD gravity bleed through the lines, eventually to wheel cylinders. IF NO fluid to wheel cylinders, I'd look at proportioning block then for a blockage. Keep calm, step back, and have a beer if need be Bill. ALSO, BE PREPARED for little leaks that can start after everything is hooked up, bled, etc. at line connections

 

[Billccm]

I would say there's a blockage then. If M/C is bled, no air, put it on. Take bleeders off and install lines. ALWAYS keep eye on M/C. It SHOULD gravity bleed through the lines, eventually to wheel cylinders. IF NO fluid to wheel cylinders, I'd look at proportioning block then for a blockage. Keep calm, step back, and have a beer if need be Bill. ALSO, BE PREPARED for little leaks that can start after everything is hooked up, bled, etc. at line connections

I'm with you 100%. I figured the portioning block was suspect, but thinking out loud I thought why would both front and rear be blocked? So, I cracked the lines INTO the proportioning block-nada-not even a drip. Even left the lines loose for 15 minutes thinking EVENTUALLY fluid has to make it's way down. NOTHING. That's why I took the master cylinder off AGAIN.

I'm sending out help requests to some of my mopar friends locally. I don't want them to turn a wrench, but just check and verify as I move along. Unfortunately I will be busy the next few weekends, so I won't be back to the Road Runner until mid June. Maybe that is good as I'll clear some frustrations.................

 

[rrTor-Red]

If going to be gone for a bit, make sure the M/C stays full at least would be my suggestion

 

[beanhead]

Don't know if this is relevant, but last MC I did, came with the plastic tubes and push-in nozzles for bench bleeding. A teeny little piece of one of the nozzles broke off in the line port and was blocking fluid, I got lucky that by pressing the pushrod the fluid pushed the fragment against the port, where I could see it in there...took me 30 minutes to dig it out with a push pin and needle nose pliers...stressed me out but I eventually got it. Maybe, (it might be messy) take the lines off, hold a container or even a rag next to the master and actuate it, just to make sure fluid squirts out. If no squirt you know for sure it's a master issue, internal blockage or pushrod/plunger

 

[69L48Z27]

I'm about ready to embark on this very same adventure. If found a 15/16" MC, looks like the one pictured above, DBMC15.

Regarding bleeding, the gravity bleed thing never worked for me. Only time that works is when I pull something apart and it keeps dripping, but never when I want to bleed anything.

Here's what works for me, numerous cars. Get a hand pump that goes over the bleeders. Pump it up and then crack the bleeder. This will drag it through the system. Once you have fluid at the wheels then go to the two man method.

 

[rrTor-Red]

Both methods will work eventually. One way or the other, fluid will come out. The problem could be what 69L.. stated above. In my case, it was the wrong bleeders. The bleeder kit I got for the M/C had a fine and course threads in them but didn't realize it until I put my glasses on and saw that I put the wrong one in. That was why mine was sucking air and wouldn't bleed properly

 

[Billccm]

New master cylinder received, and just one pump with my thumb I can tell it's different from the other one. Much stouter and difficult to press a 1/4 inch.

Good or bad, right or wrong, I bought a mityvac. I realize most of you dislike these, but I'm giving it a try. Impressed with mityvac. When the first page of the owners manual has a parts list and contact for support I know it's not a disposable tool. Even has rebuilding instructions.

Wish me luck. Going to tackle this again Friday night.

 

[Billccm]

What am I doing wrong?

Bench bled the master cylinder off the car. Nice and strong and no bubbles. Installed master cylinder and hooked up lines.

Using the Mityvac, bled the passenger rear wheel. No bubbles. Refilled reservoir. Using Mityvac, bled drivers rear wheel. No bubbles. Refilled reservoir.

Moved to passenger front caliper. NOTHING. Hard to hold a vacuum. Maybe I'm sucking air somewhere? Check all lines, loosen all lines, retighten all lines. Add more Teflon tape to bleeder. Build vacuum to 20 inches. Crack bleeder, vacuum SLOWLY drops, pump vacuum more. NOTHING. No fluid, nothing.

Try drivers side front caliper; same thing. Maybe I'm sucking air somewhere? Check all lines, loosen all lines, retighten all lines. Add more Teflon tape to bleeder. Build vacuum to 20 inches. Crack bleeder, vacuum SLOWLY drops, pump vacuum more.

Take bleeders out completely for a gravity bleed-NOTHING-not a drop of fluid anywhere.

Could InLine tube have sent me a blocked line?????? I checked the banjo bolts, washer on top and bottom like service manual shows. No fluid when I took the banjo lines off????

My bag of tricks is empty. I'd appreciate anything to check.

 

[beanhead]

This sucks because you have everything installed, but I would take off the MC front brake feed line at the valve and check for fluid. If it's getting to that point, you'll have to remove the lines from the output side of the valve and push the pedal...messy I know but you can isolate the point at which you're losing flow(blocked line or valve problem etc) Make double sure your lines/valve setup is all hooked up correctly too, that crap's confusing sometimes.....

 

[Billccm]

I cracked the line going into the top of the proprtioning block, which is the front brakes, and I got one drop of fluid. Not going to install the brake pedal until I think more. That was last Friday's mistake.

 

[NJRR]

I cracked the line going into the top of the proprtioning block, which is the front brakes, and I got one drop of fluid. Not going to install the brake pedal until I think more. That was last Friday's mistake.

If you bench bled the MC, then the output for the front on the MC isn't clogged. If you're not getting fluid from there to the prop valve, sounds like that line is clogged. Did you check to see if it got kinked/bent? You can also get a length of brake line and run it directly from MC to the prop valve, without bending it to fit in the car, and see if you get pressure/fluid going through. That will tell you if the new Inline tube is clogged.

 

[Billccm]

The lines are all new from InLine tube, but that probably does not mean much. No bends other than a few tweaks to get the lines to line up. I do not see any damage and felt by touch for any issues.

One item I noticed when cleaning up tonight. The jar from the Mityvac had specs of black sand looking stuff. Not much, but noticeable and I know it was not there from the rear bleed as I emptied the jar after each side.

 

[rrTor-Red]

The two front lines could possibly be clogged or have crap in them, yes but I have my doubts. I would concentrate on the proportioning valve myself first.

Get some plastic plugs, take ALL the lines off of the valve and plug them with the plugs. On the TWO front lines, take them COMPLETELY off of the caliper ends as well. Once off, force fluid into the valve and make sure there's fluid coming out, looking and checking for "specs of black sand looking stuff". IF the valve looks clean, has fluid running out, good then re-install. Take some brake clean and squirt ALOT of it in the TWO front lines and then use some compressed air to blow it out and dry, and check for "specs of black sand looking stuff".

Now on the lines going into the valve, here's what I'd do: Take ALL of that Teflon back off of the ends of the lines and clean them good. Then re-apply the tape, making sure the tape is 2-3 threads from the ends. DO NOT completely cover the threads with new tape. I have seen people who has applied this tape but put it all the way on the threads. BUT once the ends start to screw into the valve, there's little pieces of the tape that gets shredded off and is collected/mashed at the end, inside the valve. The little pieces of tape then prevents good fluid from going into the line(s), to the caliper, then the calipers can't be bled.

What I've stated is what I've personally experienced while working on airplanes and cars as my hobby. Also, I'm almost sure there's some members living in the Tucson area that can come over who can give you a hand. It's frustrating and can drive a person crazy but just keep calm.