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The rod should be within an 1/8" of the depth of the master?

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Typical disc brake conversion thread ...with the usual "problems" and misconceptions, a few of the responses are spot on, .....



I've done countless swaps over the decades using the 73 B body/ FMJ spindles, along with using the pin type caliper, on 66-70 B bodies, 70-4 E bodies, and the 71-2 B bodies, this family of cars are pretty much the same, with regards to sharing the same design/componets,....I've NEVER had an issue using the 73/FMJ "tall" spindle, no bumpsteer issues, or alignment problems, as some have proposed/theorize....


1st problem, sounds like you have the calipers mounted rearward, if so you can relocate them to the front upward position, by swapping the spindles left to right/drivers to pass/pass to drivers, the spindle design is symetrical in regards to the spindle angle/position, all that changes is the calipers location from rear to upper front/forward, use the 70-72 calipers/hoses (pin type)....get rid of the DISTRIBUTION DRUM block and use the correct PROPRTIONING VALVE,...get rid of the adjustable PROPORTIONING VALVE, not needed in your application....use a 1" maximum bore DISC/DRUM master cylinder 70-72 B/E application, regarding the booster, the single diaphrams, drum or disc, are all 10 3/4 diaphrams, pretty much all the same....the pushrod to bore gap for the master cylinder/booster pushrod clearance should be no less than .060 (ideal) to a max of .100


...simple guidelines, posting some pics of your current set-up, could help ID some prbplems/help


Mike

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Also the lower control arms on a 73 B body are the same as your 70 B body .

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That's not true.
The 73 B body lower control arm is different than a 1972 - 1962 B body LCA.

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Been there and done that....I had the exact same issue with another build. The PO had put on the 73-up spindles. I swapped in the A body ones and it was solved.

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Also the lower control arms on a 73 B body are the same as your 70 B body .

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That's not true.
The 73 B body lower control arm is different than a 1972 - 1962 B body LCA.

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Didn't know that , what changed .

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73 was the first year of the bubber isolated K member.

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Also the lower control arms on a 73 B body are the same as your 70 B body .

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That's not true.
The 73 B body lower control arm is different than a 1972 - 1962 B body LCA.

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Didn't know that , what changed .

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73 was the first year of the bubber isolated K member.

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Also the lower control arms on a 73 B body are the same as your 70 B body .

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That's not true.
The 73 B body lower control arm is different than a 1972 - 1962 B body LCA.

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Didn't know that , what changed .

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73 was the first year of the bubber isolated K member.

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That I know , what does the LCA look like though ?

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Also the lower control arms on a 73 B body are the same as your 70 B body .

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That's not true.
The 73 B body lower control arm is different than a 1972 - 1962 B body LCA.

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Didn't know that , what changed .

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Everything.

73 was the first year of the bubber isolated K member.

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That I know , what does the LCA look like though ?

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WOW not even close

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Well from the posts in this thread and some helpful pm's, I plan to buy a new disc brake proportioning block, lines, 70 Challenger calipers and hoses. I will retain the B spindles and switch sides so the caliper is front mounted. That should cure the interference issue and then I can tackle the lack of braking performance. Who knows, maybe by replacing all those parts, that problem may go away as well. We'll see...

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Look for a used one(proportioning valve), imo. I've read on here about too many problems with new one's.

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ON MY 70 challenger, originally drums, i have the 73a body set up using the stock distribution block and an adjustable valve in the rear line.
works exactly the same as my 74 cuda that has all stock disk brakes

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Well from the posts in this thread and some helpful pm's, I plan to buy a new disc brake proportioning block, lines, 70 Challenger calipers and hoses. I will retain the B spindles and switch sides so the caliper is front mounted. That should cure the interference issue and then I can tackle the lack of braking performance. Who knows, maybe by replacing all those parts, that problem may go away as well. We'll see...

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No. 70 Challenger calipers are pin mounted. So to run them you need pin type caliper adapters (used only) and pin hardware kit.

Sounds like you need 73-76 A-body slider calipers because of hose orientation?? Rick?

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In the first post he says that he has pin type calipers. So given that, he should be able to front hang the calipers and use factory E body hoses. Since it is a '70 model year, the anti-sway bar mounts should be in board on the LCA.

He is using the taller late B knuckle but that doesn't change the caliper position. Even the taller 11.75 rotor setup should still work with the factory hoses.

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Opps, my bad. I thought that 73 B-bodies had slider calipers and that was what he was using.

But his current situation is an easy fix with the correct banjo brake line. He needs to find the rubber one that doesn't have the 1" metal extension to it. There is an application for that. Like Aspen or Cordoba or something. Or run a custom braided line.

Here's rear mounted pin calipers with braided banjo line. The line is just routed in U shaped down from the banjo fitting and upward to the body fitting.

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Here's rear mounted pin calipers with braided banjo line. The line is just routed in U shaped down from the banjo fitting and upward to the body fitting.

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Here's rear mounted pin calipers with braided banjo line. The line is just routed in U shaped down from the banjo fitting and upward to the body fitting.

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The arrangement shown doesn't have the hose crossing the steering axis. This causes lots more twisting in the hose and mandates a very, very careful and thorough check for abrasion and "going taut" lock-to-lock, full jounce to full rebound, all combinations thereof. If the calipers must be rear hung for some reason, you are way better off moving the hardline and frame brackets to the front.

His original post led me to believe that he had pin-type calipers and they were front hung (he said LCA interference). Now he says he will move them to the front...so who knows?

Using the taller late-B knuckles may improve the camber pattern a small amount but definitely TRIPLES the bumpsteer!

Rick [/quote

My knowledge of bump steer is this. You need to form a parallelogram with these 4 points. The lower control arm pivot. The inner tie rod pivot. The lower ball joint pivot. And the outer tie rod pivot. Can you explain how raising the upper ball joint pivot affects this? I don't see it.
Doug