We didn't put much effort in trying to get the set up to work on the 8.75. When we ran into the off set problem we decided to try them on a 8.25 that we had laying around.
rear disc from grand cherokee on a 8 3/4
- Thread starter stansblue72
- Start date
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We didn't put much effort in trying to get the set up to work on the 8.75. When we ran into the off set problem we decided to try them on a 8.25 that we had laying around.
superdart
Shade Tree Tinker Gnome.....
LOL! I still have a lot of family up there, and hopefully I'll be making a road trip up there with my dad in the spring. Can't wait to visit a state with seasons. We have only two down here: 1) Really friggin hot 2) Everything is Dead and Brown...but at least the drag strips are open nearly year round (only close for December/January for surface maintenance).:-D
It looks like I'll be waiting until January to get my brake/rear axle upgrade completed on the Dart.
While it seems everyone wants to sell you the GM "metric" calipers for "their" conversions, the various Ford/Lincoln rear disc brake setups from over the years have calipers that are probably just as common, with the 38MM Varga rear caliper from 94 and newer Mustangs the most common and easiest to get. It also has the parking brake built in and would require only cable adaptation to get a working parking brake.
In the spring, after the weather breaks, I'm figuring to use 54MM single piston with parking brake calipers from a Mark VII on my stock axle ("B" body, LBP to Duster), stock roller bearing, 8 3/4 along with the matching 11 1/4" diameter Lincoln rear rotors (rotor's center pilot hole will be matched to the axles).
The 73MM front calipers these rear discs came matched with from the factory are very close in size to the 2 3/4" (69.85MM) Mopar ones and should balance out nicely with an adjustable proportioning valve because the slightly smaller Mopar caliper is going on the 11 3/4" diameter "cop car" rotors (up from the just under 11" Lincoln ones).
Making up "C" shaped caliper brackets out of 3/8" plate to mount on the inboard side of the axle housing flange with longer bolts would allow use of the stock bearing retainers.
A master cylinder with a 15/16" or 1" diameter piston should be about right for manual brakes (I think the one the Duster has now is the right diameter, but it might not have enough reservoir capacity to accommodate rear discs), and a Mustang 1 1/6" disc brake master could be adapted to the "A" body bracket, booster, and linkage for a power setup.
I'll do a step be step photo essay and share when the time comes.
In the spring, after the weather breaks, I'm figuring to use 54MM single piston with parking brake calipers from a Mark VII on my stock axle ("B" body, LBP to Duster), stock roller bearing, 8 3/4 along with the matching 11 1/4" diameter Lincoln rear rotors (rotor's center pilot hole will be matched to the axles).
The 73MM front calipers these rear discs came matched with from the factory are very close in size to the 2 3/4" (69.85MM) Mopar ones and should balance out nicely with an adjustable proportioning valve because the slightly smaller Mopar caliper is going on the 11 3/4" diameter "cop car" rotors (up from the just under 11" Lincoln ones).
Making up "C" shaped caliper brackets out of 3/8" plate to mount on the inboard side of the axle housing flange with longer bolts would allow use of the stock bearing retainers.
A master cylinder with a 15/16" or 1" diameter piston should be about right for manual brakes (I think the one the Duster has now is the right diameter, but it might not have enough reservoir capacity to accommodate rear discs), and a Mustang 1 1/6" disc brake master could be adapted to the "A" body bracket, booster, and linkage for a power setup.
I'll do a step be step photo essay and share when the time comes.
ramenth
Gratis persona
Well, if you have some extra time feel free to give me a shout and stop in while you're up this way!
ramenth
Gratis persona
Sounds like you have plan in mind. Take the pics, write up the essay, give us some seat time feelings from it and maybe put it up in tech. I would make a suggestion, though, considering these are brakes: make sure you give it seat time and get any kinks worked out with photos and descriptions of how they happened and how you fixed 'em before you post it so that if anyone tries the same set up you've got your butt covered. (As in "this is how I did it, if you don't do it this way and screwed something up, it's not my fault..." Wouldn't want an angry family member coming after you or the site...)
74scamp360
Junior Member
O Ok so it's just there's not enough caliper clearance for the 14" wheels, that makes sense. Again thanks for sharing, i'm sure that this will help a tons people a lot!! I hope to do this in the near furure, especially nowthat i've seen it done by someone else
74scamp360
Junior Member
so did the conversion to an 8 3/4 actually work??? I was reading a little further back and saw you saying that it didn't work out. I'm just interested. Are the very first pics you posted from the 8 3/4 swap or the 8 1/4??
The caliper bracket fit good on the 8 3/4 after we drilled the fifth hole in it, the same with the dust shield. The Rotor is the big bolt pattern and my axles are SBP so when we noticed the off set problem we made the decision to put the disc brakes on the 8 1/4 rear end under my son-in-laws dart.
I still need to get BBP axles for my 8 3/4 and wasn't ready to do it yet so we figured we might as well put the disc's on his ride.
If someone can figure out the off set problem on the 8 3/4 it would be a fairly easy swap.
We spent total some where around $100 to $150 to make the swap on the 8 1/4 That included new rotors.
74scamp360
Junior Member
so you just need a set of axles that will fit those rotors and it should work, or is there something else that's giving you problems? Thanks for sharing this. i know for me this is really valuable info.
Vs29H1B
Well-Known Member
I still need to get BBP axles for my 8 3/4 and wasn't ready to do it yet so we figured we might as well put the disc's on his ride.
If someone can figure out the off set problem on the 8 3/4 it would be a fairly easy swap.
We spent total some where around $100 to $150 to make the swap on the 8 1/4 That included new rotors.[/QUOTE]
Great job!
Given what you know about the swap and what's left to do (BBP axles), are you planing to re-drill the rear axles?
If someone can figure out the off set problem on the 8 3/4 it would be a fairly easy swap.
We spent total some where around $100 to $150 to make the swap on the 8 1/4 That included new rotors.[/QUOTE]
Great job!
Given what you know about the swap and what's left to do (BBP axles), are you planing to re-drill the rear axles?
JR
Pissed off senior member.
If you wanted to go with GM metrics why couldn't you take a page from the street rodders and build your own rear disk set up? www.Speedwaymotors.com should have enough of the parts for cheap to put one together. If you are going with an 8 1/4 I would stay with the Jeep stuff but if you have a 8 3/4 or something else you should be able to build something for way cheaper than any of the Wilwood kits.
http://www.speedwaymotors.com/Stamped-Steel-Brake-Hat-3-Inch-Offset,1995.html
http://www.speedwaymotors.com/GM-Caliper-Brackets,3346.html
http://www.speedwaymotors.com/GM-Weld-On-Flat-Mount-Standard-Caliper-Brackets,3348.html
http://www.speedwaymotors.com/GM-Basic-Rear-Disc-Brake-Kits,1998.html
http://www.speedwaymotors.com/Stamped-Steel-Brake-Hat-3-Inch-Offset,1995.html
http://www.speedwaymotors.com/GM-Caliper-Brackets,3346.html
http://www.speedwaymotors.com/GM-Weld-On-Flat-Mount-Standard-Caliper-Brackets,3348.html
http://www.speedwaymotors.com/GM-Basic-Rear-Disc-Brake-Kits,1998.html
74scamp360
Junior Member
That's a good idea J.R, it's a little involved for me atleast. I was interested in grand cherokee one cause i could get one super cheap. How well does all that chevy stuff work on an 8 3/4?
Good Morning J.R.
That looks interesting, would be neat to see if it would work.
That looks interesting, would be neat to see if it would work.
74scamp360
Junior Member
so greendart, the only problem you have is the rotors are a different bolt pattern then your axles? Or am i missing something
No, the only reason I mentioned the axles is that that was one of the reasons we decided to just put the set up on the 8 1/4 instead of trying to install them on the 8 3/4. I couldn't afford to buy axles right now.
The problem was the rotor would not line up with the caliper on the 8 3/4 without either making some sort of spacer to move the rotor out away from the axle hub of have longer axles made.
The problem was the rotor would not line up with the caliper on the 8 3/4 without either making some sort of spacer to move the rotor out away from the axle hub of have longer axles made.
74scamp360
Junior Member
o ok i get it now, have you thought of a way to fix that? Just curoius
my68barracuda
Well-Known Member
interesting thread,, any updates to this project?
Only update would be the brake set up seems to work okay on the 8.25. I went back to drums on the 8.75.
my68barracuda
Well-Known Member
is it the narrow flange width on the a body axel that is causing the caliper, disk alignment problem?
"note below was copied brom a internet posting"
"note below was copied brom a internet posting"
Besides the obvious bolt circle lug pattern difference between the A-body 4" BC axle and
all other passenger car 4.5" BC axles, there is a sometimes unexpected difference in the
flange that tends to cause confusion. The distance from the axle housing flange to the
wheel flange of the axle is 1/4" smaller on A-body axles than on the standard 4.5"
passenger car axle. On an A-body axle this measures 2", on 4.5" BC axles its 2.25".all other passenger car 4.5" BC axles, there is a sometimes unexpected difference in the
flange that tends to cause confusion. The distance from the axle housing flange to the
wheel flange of the axle is 1/4" smaller on A-body axles than on the standard 4.5"
Well nuts! I was all set to jump on this one till I saw 14 inch wheels won't work. I just got my 14 Inch Magnum 500's tired up and ready to go on my Dart. Guess I will be sticking with the Rear Drums for a while longer..... They have worked just fine for the last 40 years.... LOL
Later,
Bruce B.
Later,
Bruce B.
blue missile
Well-Known Member
twofosho,
have you done anything about the issues yet? Im anxious to see the play by play.
Andrew
have you done anything about the issues yet? Im anxious to see the play by play.
Andrew
TATER
Member
the rear disc have a short rubber flex hose between the caliper and hard line. I'v got the whole rear end out from a grand cherokee just the other day. Brakr cables and all.:-d:-d:-d
blue missile
Well-Known Member
Are there any up dates on this mod and its challenges?
Andrew
Andrew
The jeep brakes are on my son-in-laws 8 1/4 rear end in his dart and seem to work fine. He hasn't figured out how to hook up a E brake yet though. He bent a valve in his motor and has been working on that.
I put the rear drums back on my 8 3/4.
I put the rear drums back on my 8 3/4.
belmateo
Well-Known Member
You missed one that everybody avoids. 75-76 Imperial rear disc brakes. Hard to find but a true bolt in ONLY if you are running 15" wheels.
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