my j-body rear disks

[sharkey]

after about 6 months of planning and one test car, i finaly got my rear disks on. i used the small daytona disks, had them machined for the j-body hub, and it made it a true bolt on deal.





the machined backing plate. 92 beretta parking brake cables were used as they are 1" longer per side and are needed, unless you want to modify the cable mounting points on the axle.



the brake hoses. i used teflon core stainless braided line with the apropriate -3 ends. i used 10mm x 1.0 bevel flare to -3 adaptors on the body side. others say to use 3/8x24 inverted flare, however they do not work as out cars use metric fittings. also shown is the 7/16 to -3 banjo bolt adaptors for the calipers.



the end result. the calipers are mounted low on the back because of the way the parking brake cable exits the backing plate. there is no real downside to this, the only thing is it may not be astheticly pleasing. as for performance, it stops a little better, but not a huge amount of difference. the biggest difference is no brake fade, and very easy to service. a master cylender with a larger bore and an adjustable proportioning valve would work wonders with this setup.

[93ztwo4]

looks good man.

[Jman]

I have a front big brake kit for a 95 cavi. You might be able to adapt it to your 86 if interested. Same lug pattern.

[IsaacHayes]

Bigger fronts would be of more benefit I would think. It does make it easier to work on the rears, but the rears rarely need work. I only replaced my rear cables and shoes once.

I can't lock my wheels up on dry pavement, not with 225 or 195 width tires. I do have ABS but that doesn't trip either. Bigger fronts I'm sure would help.

They look good. Your care is free of rust it looks like! What diameter are those wheels? They look huge with not much rubber! hehe

[sharkey]

i know bigger fronts would bennifit more. i do have the 92+ j-body fronts with good pads and slotted rotors. it does stop fairly well. i did the rear disks just as one of those thing to do. the only complaint i had with the drums is in the rain they would lock up, and they are inconsistant.

i was playing with it a bit today, i found if i hit the brakes hard enough i could lock both fronts right up. i think ill end up putting an adjustable prop valve in, a little more pressure to the rears would make it a bunch better.

my car is rust free, thats one reason i bought it despite the need for body work. finding a rust free 86 here is near impossible. the wheels are 17x7 motegi's, with small 205/40/17 yokohama hs4 tires. the reason i went so small on the tires is nobody could give me a straight answer on tire sizes that work, and i did know that these would fit. im gonna need new tires for next year, these are getting a bit thin. im going to get the wheels re-finnished over winter and some 215/45/zr17s, just not sure what ones to go with.

[IsaacHayes]

Yeah I had the problem with rain and sticking when I replaced the shoes. Now it doesn't do it so much after I got working parking brake cables in. Go figure. Yeah 215 would look a lot better. 225 on my 16x7 look great.
http://www.miata.net/garage/tirecalc.html

[sharkey]

225/45 will hit everything in a 1st gen. a buddy of mine had em, they rubberd like crazy.

[IsaacHayes]

Ah, that blows. Wasn't sure how much clearance a 1st gen had.

[sharkey]

not enough. id love some 225/45/17s, but no go.