The Kelsey-Hayes Disk Brake Swap Thread

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Real good writeup. I'll add: These cars, with discs up front and 10" drums in back, were well known for scary-easy rear lockup. I took a page out of Chrysler's book and applied the fix they released in 1962 for police cars that were also prone to scary-easy rear lockup: smaller-bore cylinders in the rear brakes. Read about it here and here. Get that: they knew how to fix the problem, the parts were right there on the shelf, but despite "Consumer Reports" and every car mag bìtching about scary-easy rear lockup on A-bodies with front discs, Chrysler stared at the sky and said "Huh, looks like rain" and kept putting the big 15/16" rear wheel cylinders on.

You don't have to put up with it, and you don't have to futz with an adjustable proportioning valve. The smaller-bore cylinders are an easy, cheap bolt-on that solves the problem without creating new ones.

13/16" bore rear wheel cylinders are NAPA-United 37696, Raybestos WC37696, Wagner F113704, or ACDelco 18E268

A step smaller, 3/4" bore rear wheel cylinders are NAPA 37863, Raybestos WC37863, Bendix 34076, Wagner WC123412, Centric 134.67015, or Chrysler 4423 852.

Left = right.
 
Also: it's super important to make sure the boot grooves are clean-clean-clean on these calipers. I've seen "remanufactured" calipers with compacted rust and trash in the boot grooves, that can be chipped out with a sharp screwdriver. If there's trash in the groove, the boot won't keep out water, and then you're gonna cry at least ninety-six tears.

Early Frod Mustang disc brakes are also the Kelsey-Hayes 4-piston caliper system, using the same 1.64" bore and the same piston, and here's availability on that piston in stainless. Too bad 4-lug wheels on the Mustang instead of 5-lug, or we might have had easy availability of new hubs! This outfit offers the 4-piston A-body calipers rebuilt with the stainless pistons, and while I have no experience with them they say all their calipers are done in the United States -- if that's true, it would put them points above the "Assembled in an ISO 9001 Certified Facility at One of our Global Locations to Serve You, our Valued Customer" handwaving bulk wrap we increasingly get at the parts store.

Be very, very careful and do a hard search for the correct hardware before substituting hardware store bolts for the caliper bolts. The originals are a special shouldered design to locate the calipers correctly.
 
Good info Dan. Might I also add that if you do have rusty calipers in need of carefull resto,Evaporust saved mine. The above mentioned grooves that hold on the boot may be badly rusted or gone. Hi temp silicone might help seal and hold the boots in place. One big problem area with these calipers. Over many years of use,the glide area for the pads becomes grooved,or even notched and will cause the caliper to stick. I am thinking this area could be machine down and a new material seated to give new life. Not a machinist so have no clue if it could be done,or the cost,lol..just a thought.
 
57dodged100 said:
CALIPER TO SPINDLE BOLTS
There are many people who ask about finding the appropriate bolts that hold the calipers to the spindle. I used a grade-8 7/16 – 20 1.75” bolt from Fastenal, part # below. You can search the forum and learn that some people believe the original bolt is very unique and worth it’s weight in gold. Consider yourself lucky if you have the original bolts (I think?).
Here is a picture of a stock bolt compared to a modern replacement.

photo+1.JPG
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Does Chrysler part # 6036511AA have the correct shoulder diameter and length? It is the right thread and looks to be the right overall length. Also has thread locking compound. It is a replacement seat belt anchor bolt that you can get over the counter for about $5. If your local dealer has one you can get a measurement of the shoulder to see if it would work.
 
Thanks for the help, found a cross referens list when i googled the part number and it seems summits bendix rotors are the same:)
 
is there a conversion to use 4 1/2 bolt pattern for the a-bodys really dont want to change my wheels
 
gtxtra361 said:
is there a conversion to use 4 1/2 bolt pattern for the a-bodys really dont want to change my wheels
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If you want to use KH discs, you have to buy Mustang Rotors and have them machined to accept the seal, I believe. Not worth it IMO. I'd rather go with something else.
 
The article says updated by moderator on Wednesday. Now it makes it difficult to view any pictures of the swap. Dustin
 
@Dartsun This Article is part of the "How To" section that is currently being worked on. You'll see it real soon!! :)
 
does anyone know if there is a different set up for 67 and back or is it the same from 64 to 72?
I have a 65 and a 67 and have found a set minus prop valve and ball joints from 1970
 
Anthony Shelton said:
does anyone know if there is a different set up for 67 and back or is it the same from 64 to 72?
I have a 65 and a 67 and have found a set minus prop valve and ball joints from 1970
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As far as I know it's the same. They did change the anti rattle clips in 67 I believe. Dustin
 
Anthony Shelton said:
Thank you.
Click to expand...
I have a 1972 dart swinger that has the 10 inch drums all the way around. I have bought a very nice kelsey hayes 4 piston setup that came from a 1970 dart 340 and have been wanting to install them for years but am unclear on some things. Can i keep my upper and lower control arms or does one of them need to be changed in order to use the K-H disc setup? I have read that the upper arms has to be changed and i have also read its a direct bolt on...HELP!!
 
mopower440 said:
I have a 1972 dart swinger that has the 10 inch drums all the way around. I have bought a very nice kelsey hayes 4 piston setup that came from a 1970 dart 340 and have been wanting to install them for years but am unclear on some things. Can i keep my upper and lower control arms or does one of them need to be changed in order to use the K-H disc setup? I have read that the upper arms has to be changed and i have also read its a direct bolt on...HELP!!
Click to expand...

UCA's & LCA's are the same.
You leave them alone.
You change your LOWER ball joint over to disc brake ones, or drill your existing ball joint mouting bolt holes out from 1/2 inch, to 9/16 each.
That's about it. Easy peasy.
 
hemi71x said:
UCA's & LCA's are the same.
You leave them alone.
You change your LOWER ball joint over to disc brake ones, or drill your existing ball joint mouting bolt holes out from 1/2 inch, to 9/16 each.
That's about it. Easy peasy.
Click to expand...
awesome!! easy enough. Ok, next question, i want to install new balljoints in upper and lower control arms while im doing the brake swap,. is this possible to do at home and if so, what do i need to do it? Also, when doing the brake swap, do i have to release the tension on the torsion bars?
 
No you do not have to release tension on the bars. Make sure you order disc brake lower ball joints they have a different size bolt opening than drum ones. Most likely need a pickle fork and a ball joint socket for the upper ball joint. Dustin
 
Yes, if you are swapping the spindle you will have to back off the preload on the t-bars.

Upper ball joint takes a special socket. It can be done at home. The upper ball joint is easier to do with the control arm still attached after the spindle is out, it takes a bit of leverage to get the ball joint in and out. I use a rather large breaker bar to get it moving. Lower is standard, "normal" hardware. For the lower you will have to remove the rotor or drum to get to the bolt heads. You will have to hold the bolt stationary while you break the nuts free. You will want to at least loosen these a little before you remove the spindle from the car. If you are using an impact gun on the floor or bench it is no big deal, but it is nice to have the car hold the spindle when you break those bolts free initially.

The larger upper ball joint / different control arm that you probably heard about is needed when swapping to '73-'76 A-body single piston style brakes and the matching spindle. The older style K-H disc spindle uses the smaller ball joint.
 
Dartsun said:
No you do not have to release tension on the bars. Make sure you order disc brake lower ball joints they have a different size bolt opening than drum ones. Most likely need a pickle fork and a ball joint socket for the upper ball joint. Dustin
Click to expand...
Can you really get away with swapping the spindle without backing off the t-bar?
 
anyone know where to buy the upper ball joint socket reasonably?
 
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