Disc Brake Conversion

Am installing disc brakes on my 52 m38. Got adapter plates for the conversion and am planning on using calipers, guide pins, pads and hoses from a Chev caprice 78 to 93. using rotors from Grand Cherokee 93-98. My question is the backing plates, obviously the 52 had 9inch brakes and the backing plates are really too small to afford any protection. Should I get 11 inch plates or can I choose to run without them? Also thought I may have read something that the plate acts as a retainer and to simply turn the the plate around? By the way got my adapter plates from jimmojeep.com up in Sherbrooke, Canada.

 

I don't know how your adapter is set up, but you should't need "backing plates" for disk brakes. You may be thinking of the splash shields that you see inboard of the rotors on factory disc setups. I don't know if the old backing plate would clear the rotor for that to work as a splash guard. Lots of folks mangle the splash guards and then just end up tossing them. I did. Even if the backing plate from an 11 inch drum would work, it would be a shamefuul waste of an 11 inch backing plate. That is the key piece for an 11" drum conversion. If you've got 11" backing plates lying around, there are folks who would eagerly trade you factory splash shields for them.

 

aren't the backing plates different animals for drum and disc?:?

 

No I don't have 11 inch plates. Only the 9 inch that were on the 52. The adapter bolts to the flange on the axle but not sure if the old plate is used as a retainer?

 

Don't know if they are any different but thought i read in a write up that you use them and turn them backwards. Hoping someone elso may remember that!!

 

You don't need the dust shields, they just collect stuff. You may check on the rotors, 93-98 grand cherokees are a 5 on 4 1/2 pattern and your m38 is 5 on 5 1/2.

 

Sorry for the delay. Took picture of the adapter and am trying to load it here but having trouble. Have a Mac. Thankds for info on rotors. Was told by supplier to use the Grand Cherokee. Will continue to try and get picture of adapter plate.

 

You may find that the car calipers don not fit either. You need calipers off of a 75 to 85 1/2 ton Chevy 4 x 4.

 

If you use the search, you will find all the info.

 

Probably correct on the rotors from a 77-78 cj, but wouldn't the calipers really depend on these adapter plates that I have?

 

For a 5 x 5.5 bolt patern he does say to use gmc 1/2 ton pick up 88-92 rotors and to drill the bolt pattern for the adapter using 9/16 drill. These adapters do fit many applications (land rover, dodge, ford, etc.). After reading his instuctions he is the one that is saying if the backing plate is influencing pressure on the bearing to cut around the bearing plate and reuse. View attachment 15909

 

How about this setup?:
http://completeoffroad.com/wsm/c-141_dana_25_27_30_cj_disc_brake_kit.html

 

this looks like a neat setup http://completeoffroad.com/wsm/i-1309_cj_jeep_disc_brake_kit_dana_25_27_30.html but seems awfully expensive, but complete. Seems like you could put a 30 with disc already on it as inexpensively, unless you had to regear...

 

Adapter plates ran $45 a pair. Don't have to drill out the rotor just the adapter plate. Surprised no one has used them as I found them on e-bay.

 

Probably because you can use Chevrolet or Jeep caliper brackets that are bolt on, no drilling, and are oem parts for inspection purposes for about the same money or sometimes less, and use common, inexpensive parts like GM calipers, Jeep/Scout rotors, etc., etc.

R&P sells a similar set up as Complete Off Road for about the same money but all the parts are new except for the caliper brackets which are actually sand blasted and powder coated instead of still greasy and rusty. Nickmil