Re: Front Disk Brake Conversion not working as expected
[Re: 1970440RT]
#1084412
09/29/11 07:45 AM
09/29/11 07:45 AM
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Joined: Dec 2007
Posts: 18,165 Mass
DAYCLONA
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I Live Here
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Posts: 18,165
Mass
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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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Re: Front Disk Brake Conversion not working as expected
[Re: DAYCLONA]
#1084413
09/29/11 08:20 AM
09/29/11 08:20 AM
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Joined: Jun 2006
Posts: 135 Pittsburgh, PA
1970440RT
OP
member
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OP
member
Joined: Jun 2006
Posts: 135
Pittsburgh, PA
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Quote:
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
Thanks for the info Mike. I will get some parts in here for this weekend and report back the results.
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Re: Front Disk Brake Conversion not working as expected
[Re: hemi71x]
#1084415
09/29/11 10:24 AM
09/29/11 10:24 AM
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Joined: Jan 2003
Posts: 75,282 A gulag near you.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,282
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Quote:
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Also the lower control arms on a 73 B body are the same as your 70 B body .
That's not true. The 73 B body lower control arm is different than a 1972 - 1962 B body LCA.
Didn't know that , what changed .
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Re: Front Disk Brake Conversion not working as expected
[Re: 69sixpackbee]
#1084416
09/29/11 10:29 AM
09/29/11 10:29 AM
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Joined: Jan 2003
Posts: 75,282 A gulag near you.
JohnRR
I Win
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I Win
Joined: Jan 2003
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Quote:
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.
Can you explain what your problem was and how it was solved? The caliper mounts in the same place on the spindle, the spindle is just 3/8" taller at the top.
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Re: Front Disk Brake Conversion not working as expected
[Re: JohnRR]
#1084417
09/29/11 10:38 AM
09/29/11 10:38 AM
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Joined: Nov 2005
Posts: 15,126 85086
moparpollack
Lil Herman
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Lil Herman
Joined: Nov 2005
Posts: 15,126
85086
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Quote:
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Also the lower control arms on a 73 B body are the same as your 70 B body .
That's not true. The 73 B body lower control arm is different than a 1972 - 1962 B body LCA.
Didn't know that , what changed .
73 was the first year of the bubber isolated K member.
56 Plaza 63 D100 step side 67 Coronet, 68 Roadrunner, 69 Super Bees, 69 Coronet 500 convertible, 70 Roadrunner Post, 79 D150 360, and a severe case of Mopar a,d,d
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Re: Front Disk Brake Conversion not working as expected
[Re: moparpollack]
#1084419
09/29/11 02:59 PM
09/29/11 02:59 PM
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Joined: Jan 2003
Posts: 75,282 A gulag near you.
JohnRR
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I Win
Joined: Jan 2003
Posts: 75,282
A gulag near you.
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Quote:
Quote:
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Quote:
Also the lower control arms on a 73 B body are the same as your 70 B body .
That's not true. The 73 B body lower control arm is different than a 1972 - 1962 B body LCA.
Didn't know that , what changed .
73 was the first year of the bubber isolated K member.
That I know , what does the LCA look like though ?
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Re: Front Disk Brake Conversion not working as expected
[Re: JohnRR]
#1084420
09/29/11 03:16 PM
09/29/11 03:16 PM
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Joined: Nov 2003
Posts: 12,521 Western Colorado High Desert
moparmarks
I Live Here
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I Live Here
Joined: Nov 2003
Posts: 12,521
Western Colorado High Desert
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Quote:
Quote:
Quote:
Quote:
Quote:
Also the lower control arms on a 73 B body are the same as your 70 B body .
That's not true. The 73 B body lower control arm is different than a 1972 - 1962 B body LCA.
Didn't know that , what changed .
73 was the first year of the bubber isolated K member.
That I know , what does the LCA look like though ?
Everything.
Last edited by moparmarks; 09/29/11 03:17 PM.
72 Satellite Sebring Plus 440, 72 Dart 5.9 4-spd, 68 Valiant, 73 W200, 78 D100 sb, 78 D200, 98 DAKOTA, . Moparmarks Parts & Restorations Desert Mopar Metal Grand Jct. CO 970-261-7039 http://moparmark.com/motormangj@gmail.com
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Re: Front Disk Brake Conversion not working as expected
[Re: moparmarks]
#1084421
09/29/11 03:17 PM
09/29/11 03:17 PM
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Joined: Jan 2003
Posts: 75,282 A gulag near you.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,282
A gulag near you.
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Quote:
Quote:
Quote:
Quote:
Quote:
Quote:
Also the lower control arms on a 73 B body are the same as your 70 B body .
That's not true. The 73 B body lower control arm is different than a 1972 - 1962 B body LCA.
Didn't know that , what changed .
Everything.
73 was the first year of the bubber isolated K member.
That I know , what does the LCA look like though ?
WOW not even close
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Re: Front Disk Brake Conversion not working as expected
[Re: 1970440RT]
#1084422
09/29/11 03:24 PM
09/29/11 03:24 PM
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Joined: Feb 2005
Posts: 28,312 Cincinnati, Ohio
Challenger 1
Too Many Posts
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Too Many Posts
Joined: Feb 2005
Posts: 28,312
Cincinnati, Ohio
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Quote:
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...
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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Re: Front Disk Brake Conversion not working as expected
[Re: 1970440RT]
#1084424
09/29/11 11:14 PM
09/29/11 11:14 PM
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Joined: Sep 2003
Posts: 1,688 Marlboro, NY, USA
Rick_Ehrenberg
top fuel
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top fuel
Joined: Sep 2003
Posts: 1,688
Marlboro, NY, USA
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Lots to wade thru here....so I'll just make a few points.
It sounds like he has the drum Tee with an adjustable valve in the rear line. That's all you need...ever. BUT, its possible he has the valve plumbed in BACKWARDS, that'd give the symptoms he describes.
I'm not much on power boosters, but the comments on drum booster runout on disc swaps (pedal pressure skyrocketing) are well taken.
Reversing the caliper mountings from OEM prevents the flex line from crossing the steering axis (unless you move the hardline and frame bracket) and can be real dangerous (hose goes taut, abrades, etc.)
Gotta run...
Rick
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Re: Front Disk Brake Conversion not working as expected
[Re: 05dakota]
#1084425
09/30/11 08:22 AM
09/30/11 08:22 AM
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Joined: May 2005
Posts: 4,882 Florida
BDW
master
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master
Joined: May 2005
Posts: 4,882
Florida
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Quote:
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
Same here, I'd look into the plumbing or booster before spending money on a new proportioning valve. I actually didn't even add the adjustable valve on the rears, just changed over to the smaller 7/8" wheel cylinders.
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Re: Front Disk Brake Conversion not working as expected
[Re: 1970440RT]
#1084426
10/01/11 02:01 AM
10/01/11 02:01 AM
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Joined: Jan 2003
Posts: 27,558 So Cal
autoxcuda
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,558
So Cal
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Quote:
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...
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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Re: Front Disk Brake Conversion not working as expected
[Re: autoxcuda]
#1084429
10/01/11 07:52 AM
10/01/11 07:52 AM
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Joined: Sep 2003
Posts: 1,688 Marlboro, NY, USA
Rick_Ehrenberg
top fuel
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top fuel
Joined: Sep 2003
Posts: 1,688
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Quote:
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.
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
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Re: Front Disk Brake Conversion not working as expected
[Re: Rick_Ehrenberg]
#1084430
10/01/11 09:25 AM
10/01/11 09:25 AM
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Joined: Mar 2006
Posts: 9,982 MI, usa
dvw
master
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master
Joined: Mar 2006
Posts: 9,982
MI, usa
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Quote:
Quote:
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.
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
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