SBP DISC to LBP DISC SWAP- 72 Swinger

Looking to swap my 5x4 front disc to a 5x4.5 front disc set up. Would I need upper control arms for the swap? I have spoken to two companies offering front brake kits for 900.00 and they can't tell me what I specifically need because the kits were made for DRUM to Disc conversions. Please help with any info you guys may have because I've read these forums to death and can't find the answer to my question. I'm thinking I need spindles, calipers, rotors, bearings, and seals, prop valve and power booster(going power). Do I need Upper arms?
Any good avenues for kits like this? Thanks a mill to all of you for answering!

-Paul

You will need the upper control arms, the kelsey hayes disks used the small upper ball joint. The prop valve should be the same, I wouldn't worry about that because you're already disk/drum.

You can get some sleeves for the small ball joints to use them with the later spindles, Dr. Diff sells them for $50 HERE. Otherwise you'll need the big ball joint uppers.

Don't know about a kit, but you can pull everything you need except the upper control arms off of any F/M or J body, so you should be able to get what you need at the local wrecking yard.

And I would think you can sell your Kelsey Hayes set up for a pretty penny!

EDIT:


Here's a list of all the Mopars that use the same 10.98" rotor. You can also pull spindles and calipers off of any of these cars. Some will have pin type calipers, but if you grab everything from the spindle out you'll get the right caliper brackets. Some of them also had the 11.75" rotors from '76 to '81.

CHRYSLER CORDOBA (1975 - 1983)
CHRYSLER FIFTH AVENUE (1983 - 1989)
CHRYSLER IMPERIAL (1981 - 1983)
CHRYSLER LEBARON (1977 - 1981)
CHRYSLER NEW YORKER 1982
CHRYSLER TOWN & COUNTRY (1978 - 1981)
DODGE ASPEN (1976 - 1980)
DODGE CHALLENGER (1973 - 1974)
DODGE CHARGER (1973 - 1976)
DODGE CORONET (1973 - 1975)
DODGE DART (1973 - 1976)
DODGE DIPLOMAT (1977 - 1989)
DODGE MIRADA (1980 - 1983)
PLYMOUTH BARRACUDA (1973 - 1974)
PLYMOUTH CARAVELLE (1978 - 1985)
PLYMOUTH CUDA (1973 - 1974)
PLYMOUTH DUSTER (1973 - 1976)
PLYMOUTH FURY 1975
PLYMOUTH GRAN FURY (1982 - 1989)
PLYMOUTH SATELLITE (1973 - 1974)
PLYMOUTH SCAMP (1973 - 1976)
PLYMOUTH VALIANT (1973 - 1976)
PLYMOUTH VOLARE (1976 - 1980)

If you're thinking kit , check out RMS
Bill has a very nice kit and it was a good chunk less than 900.00 as I recall.
It is for the large joint , but that isn't a bad upgrade to consider.

Thanks buddy. I'll definitely do that. I'm looking to buy soon and wanted to clear some things up. Thanks for all the info!

Hey guys I need to do drum to disc on a 72 Valiant. I used the list above and found a 85 Diplomat and got the set up last weekend. Now I see on Mopar Action On-Line there is a thread called "Disc-O-Tech" that says not to use the taller knuckles found on 73 and up B/F/J/M/R cars and they should measure 4-9/16" from the back spindle hole to the underside of the top ball joint connection. If taller than this you will change the camber and bump steer effects. Not sure what bump steer is. The Diplos are about 1/4" taller. What will using these taller knuckles do to the car steering?

For the OP, 72blunblu covered the upper situation. You'll need to run a bbj upper control arm (73-76 A body) or sleeve on your existing arms.

The bumpsteer thing is so overblown it's crazy. I run nothing but the FMJ on my a-body cars anymore. Never broken a ball joint or had bumpsteer. Look on the tech pages at Big Block Dart for the write up regarding the issue.

StephenShaw said:

Hey guys I need to do drum to disc on a 72 Valiant. I used the list above and found a 85 Diplomat and got the set up last weekend. Now I see on Mopar Action On-Line there is a thread called "Disc-O-Tech" that says not to use the taller knuckles found on 73 and up B/F/J/M/R cars and they should measure 4-9/16" from the back spindle hole to the underside of the top ball joint connection. If taller than this you will change the camber and bump steer effects. Not sure what bump steer is. The Diplos are about 1/4" taller. What will using these taller knuckles do to the car steering?

Click to expand...

The Mopar Action article does a HUGE disservice to this swap. Basically, they throw a ton of BS out there without even investigating the actual changes.

Mopar Muscle actually did the swap and analyzed the geometry, and found that while there is a little bit more toe change because of the spindles, they also improve the camber gain throughout the suspension travel. The toe change (the dreaded bump steer) is almost insignificant. But, the camber gain is very beneficial, even in small amounts.

The Mopar Muscle article is here

Basically, for a street car, you probably won't notice any difference between the '73 up A body spindles and F/M/J stuff. Except of course in your wallet, because you can get the F/M/J spindles from most wrecking yards still. I paid $60 at PickNPull for a set of spindles with caliper brackets off a Diplomat.

Thanks for the info. I feel better now as I just spent $140 for the set up (little more costly in Calif) and this will be my 16 yo daughters car. I was invisioning her boucing off the road like they used to say all Corvairs did. That was a hoax as well. I will proceed with the install.

Need some more help. I got the '85 Diplomat discs to put on my '72 front drum Scamp. I now see that the knuckle on the '85 set up has bolts through the spindle that thread into the knuckle. The '74 knuckles have smooth holes. Do I just get longer bolts and have the nuts against the knuckles? The '85 bolts have extremely flat heads, I assume to clear the discs. If I get longer standard head bolts will they hit the discs? What have you guys done to fix this? I wouldn't want to modify new bolt heads and have them fail.

Stephen Shaw

StephenShaw said:

Thanks for the info. I feel better now as I just spent $140 for the set up (little more costly in Calif) and this will be my 16 yo daughters car. I was invisioning her boucing off the road like they used to say all Corvairs did. That was a hoax as well. I will proceed with
the install.

Click to expand...

Uh, I'm in California too, so, sorry about that. Someone made some money off you. :banghead:

StephenShaw said:

Need some more help. I got the '85 Diplomat discs to put on my '72 front drum Scamp. I now see that the knuckle on the '85 set up has bolts through the spindle that thread into the knuckle. The '74 knuckles have smooth holes. Do I just get longer bolts and have the nuts against the knuckles? The '85 bolts have extremely flat heads, I assume to clear the discs. If I get longer standard head bolts will they hit the discs? What have you guys done to fix this? I wouldn't want to modify new bolt heads and have them fail.

Stephen Shaw

Click to expand...

Yes, you'll need longer bolts as the FMJ ones won't be long enough. Someone solved this issue already on here, I'll try and find the thread.

**EDIT**
Ok, so I found one thread where a member stated they just used grade 8 bolts and nuts. No mention of any grinding.

I would just buy a set of grade 8's and mount them up. Check the clearance between the head of the bolt and the rotor. Doesn't have to be much, just enough to allow for a little play in the wheel bearings or a little rotor warping down the road. I'd want a little extra just so if the wheel bearings wore out there wouldn't be any chance of the bolts hitting the rotors. But you're still not talking about a ton of space, a 1/16" would be plenty. Anyway, if there isn't a ton of clearance, I'd just grind the heads of the bolts to fit. As long as you don't get the bolt red hot, it won't effect the strength of the bolt. And I don't think you'll need to make them as thin as the originals either, so it shouldn't be a huge issue.

You can also use the stock bolts from a '73-'76 A body spindle, they're long enough and work fine, if you can find a set.

Good info 72. You have me wondering if I can get the caliper brackets off the cars you mentioned and put bigger rotors on my demon (73 and up brakes) with out any modifications.

Thanks, Aj

Aj408 said:

Good info 72. You have me wondering if I can get the caliper brackets off the cars you mentioned and put bigger rotors on my demon (73 and up brakes) with out any modifications.

Thanks, Aj

Click to expand...

These are the only cars you're going to find 11.75" rotors and caliper brackets on. There's a little overlap with what I posted above, but the FMJ cars didn't come with them. B, C, and a few R bodies had them. If one does show up in the yard, HURRY. I've missed a couple sets on cars that hit the yard the same day I went, missed them by hours.

But yes, if you have '73 up disk spindles then all you need are the caliper brackets and rotors, you even re-use your calipers. Bolt on deal. You do need 15" rims though.

CHRYSLER CORDOBA (1976 - 1979)
CHRYSLER NEW YORKER (1979 - 1981)
CHRYSLER NEWPORT (1979 - 1981)
DODGE CHARGER (1976 - 1978 )
DODGE CORONET (1975 - 1976)
DODGE MAGNUM 1979
DODGE MONACO (1977 - 1978 )
DODGE ST. REGIS (1979 - 1981)
PLYMOUTH FURY (1976 - 1978 )
PLYMOUTH FURY SALON (1977 - 1978 )
PLYMOUTH FURY SPORT (1977 - 1978 )
PLYMOUTH FURY SPORT SUBURBAN (1977 - 1978 )
PLYMOUTH FURY SUBURBAN (1977 - 1978 )
PLYMOUTH GRAN FURY (1980 - 1981)
PLYMOUTH GRAN FURY SALON 1980

72bluNblu said:

Uh, I'm in California too, so, sorry about that. Someone made some money off you. :banghead:



Yes, you'll need longer bolts as the FMJ ones won't be long enough. Someone solved this issue already on here, I'll try and find the thread.

**EDIT**
Ok, so I found one thread where a member stated they just used grade 8 bolts and nuts. No mention of any grinding.

I would just buy a set of grade 8's and mount them up. Check the clearance between the head of the bolt and the rotor. Doesn't have to be much, just enough to allow for a little play in the wheel bearings or a little rotor warping down the road. I'd want a little extra just so if the wheel bearings wore out there wouldn't be any chance of the bolts hitting the rotors. But you're still not talking about a ton of space, a 1/16" would be plenty. Anyway, if there isn't a ton of clearance, I'd just grind the heads of the bolts to fit. As long as you don't get the bolt red hot, it won't effect the strength of the bolt. And I don't think you'll need to make them as thin as the originals either, so it shouldn't be a huge issue.

You can also use the stock bolts from a '73-'76 A body spindle, they're long enough and work fine, if you can find a set.

Click to expand...

72, thanks I will do the Grade 8 bolts. Seems PickNPull are all up north. I'm in Socal and have to deal with Pick Your Part and most others charge about the same. PYP now has an on line system to tell you when the cars hit the lot so I guess I am paying for that convenience. Thanks again. SS