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Author Topic: Disc brake conversion  (Read 1382 times)

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Offline Gearhead

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Disc brake conversion
« on: July 01, 2008, 01:41:34 PM »
It's time to upgrade the rear brakes on my YJ.

What it has now ,      a dana 44 ( 88 grand wagoneer ) drum brakes w/ all new parts when I swapped it in  2005

The drums worked  for a while , doing the intended job  ,  I've changed the linings once , they need to be done again , it's mud that is building up and shortening the life of the linings and drums.    A disc conversion has been on the list of things to do for a while .

What I've got  rounded up ,  to get started ..............

New rotors  , front 88 chev 3/4 ton reg cab 4x4  ( six lug )
Reman calipers  ,  85 Chev monte carlo  ( 5 1/2 "  c to c )
New  flex hoses , some hard lines , banjo bolts , a  combination valve from a ZJ  w/ 4 wheel disc brakes



What I  need now is mounting brackets    like this  ....     http://www.aa-mfg.com/pdshop/shop/item.aspx?itemid=20



AND  ............ I need to have a parking brake !   ,    thinking about  a Mico lever lock   , I need to find a dealer for Mico products??????

Greggs ?  Danco ?  , ........  any suggestions or non ghetto alternatives to a strong parking brake  , With Mico I can have the option of four wheel hydraulic parking brakes.
 


I'm in    Whitehorse /  Yukon       right now and will be looking to get this started when I get back.

Does evolution stock the caliper brackets for GM  metric calipers ?    5 1/2" center to center mounting bolts ? or , should I just order the A&A mfg brackets on line ?


Also , I realize , a hydraulic parking brake is not legal , a mechanical brake is . Knowing that and having owned a vehicle in the past with a Mico lock , I'm OK with using it again .   


« Last Edit: July 04, 2008, 08:49:58 PM by Gearhead »

Offline stroker sahara

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Re: Disc brake conversion
« Reply #1 on: July 01, 2008, 04:11:06 PM »
You could always get some calipers from a Cadillac with the 10 bolt rear disc setup. The calipers are virtually the same as the ones you plan to use, just with park brake as well. As for the rotors, are they the same thickness as the 1/2 ton rotors? I believe it is important that they are the 1" thick ones.
If you want to run with the big dogs you have to be able to pee in the tall grass.


1989 YJ SOA, 36" SX, 4.6 Stroker...

Offline Gearhead

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Re: Disc brake conversion
« Reply #2 on: July 01, 2008, 05:59:38 PM »
You could always get some calipers from a Cadillac with the 10 bolt rear disc setup. The calipers are virtually the same as the ones you plan to use, just with park brake as well. As for the rotors, are they the same thickness as the 1/2 ton rotors? I believe it is important that they are the 1" thick ones.

I'm thinkin the 1/2 ton rotors are the correct thickness but are five lug.  Reg cab 3/4 ton are one inch thick  x six lug , suburban & extended cab rotors are 1.250"

I had thought about the caddie calipers and then found out that the cable actuated park brakes are prone to siezing , a problem that exposure to mud may make worse and something I'd rather not have to deal with any longer.

Mocking up the calipers , pads and rotors while still in the parts store the other day , confirmed that the combination of parts will work. Right now my front calipers are generously sized GM  , the monte carlo calipers , I'm using on the rear axle are smaller so the bias on braking power to the front  will remain as it should. Another trivial item I should mention is ,the montecarlo calipers are larger than what is commonly found on a Ford 8.8 w/ disc brakes. 

Offline stroker sahara

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Re: Disc brake conversion
« Reply #3 on: July 01, 2008, 10:06:49 PM »
I'm thinkin the 1/2 ton rotors are the correct thickness but are five lug.  Reg cab 3/4 ton are one inch thick  x six lug , suburban & extended cab rotors are 1.250"

All 1/2 ton 4wd GM's are six lug. They are probably the same rotor for the 1/2 and 3/4 ton trucks.
Here is a link to some good info from another site that may help you.

http://www.jeeps-offroad.com/showthread.php?t=21679&highlight=disc+brake+swap+waggy
If you want to run with the big dogs you have to be able to pee in the tall grass.


1989 YJ SOA, 36" SX, 4.6 Stroker...

Offline Bnine

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Re: Disc brake conversion
« Reply #4 on: July 02, 2008, 01:24:22 PM »
Last I looked there is a set of GM metric disk brackets on evo's wall.

I prefer a swagelock ballvale in place of a micro. Micro's do leak back eventually. If you have a leak free sysem, a swage will hold pressure for months. Guys use them as a hidden theft deterrent sometimes.

Evo carries them as well.

A 2psi residual valve might be required. Mopac has them on theis small wilwood shelf, as well as willwood adjustable prop valves if that becomes an issue.

If pedal travel is to long, I can get 2 durango part numbers for larger, bolt in MC's. One is 1 1/16, and the other is 1 1/8.

I need to come over and get some stuff, and inlist some help on shimming rockers anyways. Call me when you get back bud.

I agree, the cadilacs are way to prone to seizing for our enviroment.
My Mechanic Calgary
Mobile Auto Care
403-483-1083
[email protected]

Offline Gearhead

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Re: Disc brake conversion
« Reply #5 on: July 02, 2008, 10:05:38 PM »
Last I looked there is a set of GM metric disk brackets on evo's wall.

I prefer a swagelock ballvale in place of a micro. Micro's do leak back eventually. If you have a leak free sysem, a swage will hold pressure for months. Guys use them as a hidden theft deterrent sometimes.

Evo carries them as well.

A 2psi residual valve might be required. Mopac has them on theis small wilwood shelf, as well as willwood adjustable prop valves if that becomes an issue.

If pedal travel is to long, I can get 2 durango part numbers for larger, bolt in MC's. One is 1 1/16, and the other is 1 1/8.

I need to come over and get some stuff, and inlist some help on shimming rockers anyways. Call me when you get back bud.

I agree, the cadilacs are way to prone to seizing for our enviroment.



The master cylinder I'm using now is a 1.125"  Ford E350   , less travel / more effort than the stock YJ  master cylinder , an improvement  over stock with the larger Waggy brake components. With the stock m/c the pedal was near the floor due to the lack of volume / small bore  ,    at times scary ,  trying to hold it on steep climbs if stopping  , or winching became necessary.  I'm hoping the one ton van m/c will do the job.  The front brakes have never been a concern, the calipers being of sufficient size to slow it down , even with 36's.

If all goes well this should be an afternoon project , incuding paint , however  ,  I've blurted out statements like that before and been wrong.


I'll call you bill  , there's goodies here , drug from the archives , that will be usefull to you.
« Last Edit: July 04, 2008, 08:51:03 PM by Gearhead »

Offline Bnine

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Re: Disc brake conversion
« Reply #6 on: July 03, 2008, 09:54:43 AM »
Sounds good bud.

My Mechanic Calgary
Mobile Auto Care
403-483-1083
[email protected]