Disc Brake conversion - can’t get pedal pressure

1STMP

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Im not saying it will hurt anything and i stalled them on my wifes car hoping it would correct some issues, it didnt. Everyone's directions that I've read state that they are for a MC that is at/below the calipers. I think Stranger site mention the 2lb with drums.
Please don't assume I'm arguing here. Just
trying to help the OP solve an issue.
There are 2lb residual check valves installed
on many makes that incorporate front disc's.
The pressure in the line (no pedal) is just to keep the pads from separating from the rotors
by preventing brake fluid drain back to the
MC. The MC doesn't necessarily have to be
at or below the calipers for this to happen.
My suspicion as to what is happening with the
OP's system, is he still has air in the front calipers.
I had to remove mine from the rotors and
rotate them to 12 o'clock, using a piece
of wood the same thickness as the rotor so
they had something to clamp against. I chased
the same symptoms for a week, going through
buckets of brake fluid until I did this.
 

moparedtn

Ed on the Ridge
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Hard to bleed the brakes with wheel cylinder-s cockeyed. Wonder if he solved his problem?
What I noticed also (in addition to the seemingly weird hardware arrangement as Red said)....
That axle sure looks like it's sitting at an odd pinion angle in that pic?
 

Mike67

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Please don't assume I'm arguing here. Just
trying to help the OP solve an issue.
There are 2lb residual check valves installed
on many makes that incorporate front disc's.
The pressure in the line (no pedal) is just to keep the pads from separating from the rotors
by preventing brake fluid drain back to the
MC. The MC doesn't necessarily have to be
at or below the calipers for this to happen.
My suspicion as to what is happening with the
OP's system, is he still has air in the front calipers.
I had to remove mine from the rotors and
rotate them to 12 o'clock, using a piece
of wood the same thickness as the rotor so
they had something to clamp against. I chased
the same symptoms for a week, going through
buckets of brake fluid until I did this.
No problem, not arguing, and respect your opinion and experiaence here on the forum.
All Im saying is that all the decriptions/Instructions I read during my troubleshooting woes were that the rediual valves for disc were for a low mounted mc. Of course I couldnt have read every mfgs recommendations, but there were quiet a few.
I too had to take caliper off and shim the pads and tilt the caliper to get the last remaing air out, even after using a pressure bleeder, a vacuum pump and traditional bleeding with a tube connected to the bleeder submerged in brake fluid.
 

Mike67

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Ive also seen aftermarket mc's sometimes have a spacer piston inside the pushrod bore to take up some of the preload for different configurations.
I think the main culprits of a spongy pedal are air, stroke or too large of a bore.
It might be money well spent to buy a brake line pressure gauge so that you can actually see what your mc/ pedal combinatiin is actually doing.
 

65_Satellite

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Hey guys. I did get this original problem fixed. It ended up being a bad master cylinder. After getting a new one, all 4 wheels bleed and the pedal is great. Drove it all last summer with no issues. @Red63440 what looks wrong in the pic? I have since swapped sides on the self adjusters because they were backwards but aside of that, I’ve been running it as is and haven’t had any issues. @Fran Blacker, As for the “cockeyed” wheel cylinder, it may be the photo. It mounted correctly. You may be noticing that the axle isn’t installed on that pic so the whole backing plate/brake assembly is loose. @moparedtn As for the pinion angle, yes it was wrong in that photo. The car had wedges between the axle and the spring when I got it and I’ve since removed them.
 

65_Satellite

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Also I realize you are looking at the self adjusted leg facing up. That’s because in that pic I somehow managed to snap the little spring that holds the self adjusting lever in place on that side and was waiting for doctor Diff to mail me a new one.
 
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1STMP

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Hey guys. I did get this original problem fixed. It ended up being a bad master cylinder. After getting a new one, all 4 wheels bleed and the pedal is great. Drove it all last summer with no issues. @Red63440 what looks wrong in the pic? I have since swapped sides on the self adjusters because they were backwards but aside of that, I’ve been running it as is and haven’t had any issues. @Fran Blacker, As for the “cockeyed” wheel cylinder, it may be the photo. It mounted correctly. You may be noticing that the axle isn’t installed on that pic so the whole backing plate/brake assembly is loose. @moparedtn As for the pinion angle, yes it was wrong in that photo. The car had wedges between the axle and the spring when I got it and I’ve since removed them.
Glad you got this figured out. We here can
only offer suggestions for fixes based on
past experiences and info supplied. Lots
of good people on this site.
 

Red63440

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:thumbsup::thumbsup::thumbsup::thumbsup:
Hey guys. I did get this original problem fixed. It ended up being a bad master cylinder. After getting a new one, all 4 wheels bleed and the pedal is great. Drove it all last summer with no issues. @Red63440 what looks wrong in the pic? I have since swapped sides on the self adjusters because they were backwards but aside of that, I’ve been running it as is and haven’t had any issues. @Fran Blacker, As for the “cockeyed” wheel cylinder, it may be the photo. It mounted correctly. You may be noticing that the axle isn’t installed on that pic so the whole backing plate/brake assembly is loose. @moparedtn As for the pinion angle, yes it was wrong in that photo. The car had wedges between the axle and the spring when I got it and I’ve since removed them.

It was the self adjuster but you got that taken care of:thumbsup:
 

65_Satellite

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Glad you got this figured out. We here can
only offer suggestions for fixes based on
past experiences and info supplied. Lots
of good people on this site.
That’s for sure. I’ve gotten a lot of help from many members here.
 

moparedtn

Ed on the Ridge
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Hey guys. I did get this original problem fixed. It ended up being a bad master cylinder. After getting a new one, all 4 wheels bleed and the pedal is great. Drove it all last summer with no issues. @Red63440 what looks wrong in the pic? I have since swapped sides on the self adjusters because they were backwards but aside of that, I’ve been running it as is and haven’t had any issues. @Fran Blacker, As for the “cockeyed” wheel cylinder, it may be the photo. It mounted correctly. You may be noticing that the axle isn’t installed on that pic so the whole backing plate/brake assembly is loose. @moparedtn As for the pinion angle, yes it was wrong in that photo. The car had wedges between the axle and the spring when I got it and I’ve since removed them.
Awesome, thanks for the update. Love it when things get right!
 

IRON MAN

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Guy I am looking to do a disk brake conversion for my 1970 Roadrunner what company do you recommend?
 

Billccm

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I'll 2nd Dr Diff.
 

bc3j

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Dr. Diff also. Carefully check the front port thread size of the MC on the generic kits. A lot use the GM type with a 9/16-18 threads while Mopar is 9/16-20.
 

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