Who Has done the Rear Disk Conversion

[ThisGuyUKnow]

I am sure Brock will chime in with his magic info thread link but I have read all the AMC20 disk brake conversion threads there and that I could find on google.....

Since I plan on hugging to an AMC20 axle despite everyones nay saying and since I am looking at having to replace the pinion bearings when I get back from OCS in march I am considering just completely building my 20 with one piece shaft and possibly trussing and installing disk brakes on it...

So here is what I have not really found satisfactory answers to about the conversion with 300zx rear calipers.

1st is it absolutely necessary to replace the prop valve? I read some say they did some say they didn't... which is it. Do you need to find an MC with equal size front and rear reservoirs? I have a hydraboost so my setup can push alot more pressure than even a yj vac booster so is the prop valve change only for those running with weaker brake systems like manual brakes or weaker vac boosters?

2nd I don't see any real good info on getting the emergency brake to work. I have seen a lot of references that say "my stock e brake lines bolted up" and I have seen some that say "they had to be lengthened" Which is it?

Also i saw an offhand reference that suggested you may not need to keep part of the backing plate as a spacer if you are not using one piece shafts.

 

[fzsk4p]

I am sure Brock will chime in with his magic info thread link but I have read all the AMC20 disk brake conversion threads there and that I could find on google.....

Since I plan on hugging to an AMC20 axle despite everyones nay saying and since I am looking at having to replace the pinion bearings when I get back from OCS in march I am considering just completely building my 20 with one piece shaft and possibly trussing and installing disk brakes on it...

So here is what I have not really found satisfactory answers to about the conversion with 300zx rear calipers.

1st is it absolutely necessary to replace the prop valve? I read some say they did some say they didn't... which is it. Do you need to find an MC with equal size front and rear reservoirs? I have a hydraboost so my setup can push alot more pressure than even a yj vac booster so is the prop valve change only for those running with weaker brake systems like manual brakes or weaker vac boosters?

2nd I don't see any real good info on getting the emergency brake to work. I have seen a lot of references that say "my stock e brake lines bolted up" and I have seen some that say "they had to be lengthened" Which is it?

Also i saw an offhand reference that suggested you may not need to keep part of the backing plate as a spacer if you are not using one piece shafts.

I run hydrboost on my YJ. The link is for an adjustable prop valves that takes all the guess work out. They are cheap enough that they ought to be on every brake conversion.

Search Results for brake adjustable proportioning valve - SummitRacing.com

SSBC offers a disc brake conversion kit that advertises being complete with e. brake and hardware.

SSBC :: Part Finder

Another idea is to use Ford 9 inch ends, Moser 7750`s for example. These ends will allow you to use the 8.8 disc/emegerency brake set up. Which is really a sweet set up. Conversion kits are readily available from Mountain Off Road etc.

Chrysler 8.25 axles are 29 spline so you could have a number of different companies (Moser again can help) make you up a set of axles. This way you could have disc brakes and 1 piece axle in one shot.

I`d bet the Ford 8.8 axles/brakes and custom shafts would be cheaper then the SSBC kit alone.

Of course you could just swap a complete 8.8 axle in. You would need different axles or adapters to match up the 5 on 5.5 bolt pattern. But the new axles are pretty cheap and they would be chromo`s at 31 spline and all the disc brake goodies...............For less then converting the 20.

 

[ThisGuyUKnow]

I run hydrboost on my YJ. The link is for an adjustable prop valves that takes all the guess work out. They are cheap enough that they ought to be on every brake conversion.

Search Results for brake adjustable proportioning valve - SummitRacing.com

SSBC offers a disc brake conversion kit that advertises being complete with e. brake and hardware.

SSBC :: Part Finder

Another idea is to use Ford 9 inch ends, Moser 7750`s for example. These ends will allow you to use the 8.8 disc/emegerency brake set up. Which is really a sweet set up. Conversion kits are readily available from Mountain Off Road etc.

Chrysler 8.25 axles are 29 spline so you could have a number of different companies (Moser again can help) make you up a set of axles. This way you could have disc brakes and 1 piece axle in one shot.

I`d bet the Ford 8.8 axles/brakes and custom shafts would be cheaper then the SSBC kit alone.

Of course you could just swap a complete 8.8 axle in that already has 31 spline axles and all the disc brake goodies...............For less then converting the 20.

So you are saying that i use axle shafts from a different axle in an AMC20 ? would that work? I am not looking for an axle swap to another axle that would require fiddling around with cutting and relocating spring perches and stuff. So dont think a ford 8.8 is really in the cards for my build.

 

[fzsk4p]

So you are saying that i use axle shafts from a different axle in an AMC20 ? would that work? I am not looking for an axle swap to another axle that would require fiddling around with cutting and relocating spring perches and stuff. So dont think a ford 8.8 is really in the cards for my build.

I`d give Moser a call
Moser Engineering - Moser Engineering - Home

Let then know what you want to do. Moser 7750`s which are known as the Torino big bearing ends. So you can use the Ford 8.8 disc brake/parking brake with your AMC20 .

Moser Engineering - Part # 7750 - Big Ford New Style/Torino Housing Ends

You will need the Currie 5 on 5.5 rotor. Need to specify the bolt pattern.
Currie Enterprises Racing Rear End Categories

The rest of the brake parts can be found at the auto parts store or JY.


EDIT:
Took liberty and talked to Matt at Moser.

Chromo 29 spline axles, 7750 ends, bearings and retainers would come out to about $550 bucks. Two day turn around. Moser may also be able to get you the brake rotors also.

Then all you need to do is get the calipers, backing plates etc for the 8.8 application (1995 and up Ford Explorer) at the auto parts store, JY or online.

EDIT EDIT;
Not sure how far you are from Battle Creek Michigan. But DTS
http://www.drivetrainspecialists.com/index.html

could do the whole install for you. Drop your axle off and then pick it up a few days later ready to bolt in. DTS is also a dealer for Moser.

 

[BrockGrimes]

You are right lol.
See post#28
http://www.jeep-cj.com/forums/f49/useful-info-thought-id-share-665/
I'd try it with the stock prop valve if it currently works with your system and change it as needed.
The stock one worked on a build I helped with.
Can't recall on the ebrake.
I believe I have the brake mount bracket measurements in a file if you need that.

 

[IOPort51]

I think I can make it happen with 90s GM big car rear calipers and 80s Jeep roters. The mount shouldn't be that hard to fab.

 

[jeepboy45]

Hi,
I was wondering what you did with your brake conversion...
I have a 79 CJ7 with model 20 rear end and am NOT getting rid of it either.
Did you cave in, and get rid of the model 20?
Did you do the conversion?

brian

 

[Jimbos76cj]

AMC 20 disk brakes

Checkout that link.

There is a guy on FJOA that can cut the plates out with his CNC plasma cutter.. Ill Pm you his info there.

 

[jeepboy45]

AMC 20 disk brakes

Checkout that link.

There is a guy on FJOA that can cut the plates out with his CNC plasma cutter.. Ill Pm you his info there.

thanks for that link...It looks WAY cool...and i'm going to a friends shop tomorrow to cut out the plates.

 

[RangerRick]

Before I ditched my AMC20 in favour of the Ford 8.8 with disc brakes I looked into installing discs on the AMC.

What I found was this: Clickey-Clickey Link

It is the same idea as the link to the 4WD site earlier and has more discussion about 80's 300ZX calipers and Zuke rotors that were used in the conversion.

Here's A JF discussion on the topic: Clickey-Clickey Link

One of the guys posting up there makes some brackets as an alternative to making them yourself.

I found a set of calipers and was going to make the brackets that captured more of the backing plate retainer bolts instead of only 2 or 3....... But fate intervened by then, after breaking the differential for the fourth time, I decided to shotgun the whole thing, replaced the whole axle assembly with one that had disc brakes from the factory (Ford Explorer 8.8) and never looked back.

Follow the links and feast your eyes on the photos a-plenty....

RangerRick

 

[iCEMAN]

Anyone have a better file on the bracket drawing? I tried downloading it but it comes out blurry on the measurements.

 

[jeepboy45]

Anyone have a better file on the bracket drawing? I tried downloading it but it comes out blurry on the measurements.

see if this comes out clear...

 

[iCEMAN]

Perfect, thanks jeepboy45!

 

[DOUG]

Friend of mine just did this conversion, had nothing but good things to say about these guys... 2590

 

[IOPort51]

^^If you do the math on this outfit it just looks like the best bang for the buck and the time.

 

[Clint1012]

What year did the 8.8 come out of