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73skyline

rear disc brake conversion?

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I have designed and built adaptors to mount R31 rear callipers to an MR30 Skyline rear control arms.

Unsure if the 240K is similar:ermm:

Two 6mm thick brackets side by side had the calliper in the right spot for the disc rotor.

No welding involved, which is verbotten anyway.

If you are interested, I'll post some info.

Try and steer away from the R30 callipers, compared to the R31 they are just horrible in the hand brake area.

There is some info. in the Z car forum on the R31 callipers: -

http://www.classiczcars.com/forums/showthread.php?t=25240

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I knew I had some pics. somewhere:classic:

The handbrake mechanism on the R31 callipers is so simple, easily the best choice in an upgrade:knockedou

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i was convinced by a friend that the DR30 brakes were better than the R31 calipers (piston size etc. i can't remember the argument now, but it was convincing..), but yes, the trouble is getting hold of one pair that hasn't had the hand brake assembly siezed (i have one caliper that is good)..

apparently MR30 piston bodies can be fitted to the DR30 arms (presumably it is only the mounting distance that was different).. MR30's are a little easier to find than DR30's :D

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would Nissan 240SX/Silvia cals and rotors work? here in the USA we don't have DR30s sitting around anywhere.

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Since I brought a MR30 for the EFI, I also keeped the rear disc and calipers,

the hand brake leaver doesn't have any slop, so I believe the bearings are ok.

I got this AutoCad file from 240K&Beyond a while ago, this is a mock up (out of MDF) I made.

I'm not sure how much it would cost to get made, but I think the 2 piece bracket would be cheaper to make, so I may go that way instead.

Nigel

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tm305.dwg

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My conversion consisted of:

- 280zx (1982) 10.25" rotors (don't use the 84 300zx 11.4" rotors unless you have the modern-motorsports or custom adapter) ($45)

- Nissan 200sx calipers (similar to 240sx or 2nd generation Maxima calipers) (FREE)

- Modified Nissan Maxima rear adapters. (4 bolt design, but I cut off the corner and 4th bolt hole to allow easy access so I dont have to remove the stub axle) ($80)

- Total - ($125) =)

First Here is a picture of the Z's rear drum brakes on my 1978 280z. Pretty aint it?

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After tapping on the rear with a rubber mallet, the front drum cover pops right off and behold the glory if dirty drum brakes.

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Take a sawzaw or a 4" cut off disc and cut away on the rear backing plate for the drums. Major PIA, and you have to cut it in 2 diff places, or the plate will not come off. Yes, your sawzaw or cut off disc will not get to the bottom, so I tried to cut down the the bolt holes, and I used a BIG pair of pliars and wiggled it around for a while untill the metal became fatigued enough to break. (You dont have to do this if you remove the stub axle which is a major PIA)

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Yay it came off.. (2 hrs later SOB)

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This is my caliper choice. I got them from a friend for free, I later found out the are from a 200sx. (very very similar to the 240sx and 2nd generation Maxima calipers) I LOVE these because I was able to use the STOCK rubber lines! score!

NOW one important note which isnt found typically on write-ups. "L" normally means "drivers side" and "R" means passenger side. Well on a Z with a different geometry due to the bracket, you must SWITCH the sides around. I know annoying huh?! Trust me I found out the right way

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Now my e-brake arm was fixed on the cast caliper. The 240sx caliper allows some adjustment and is removable, but the arm will be VERY close to the rear sway bars, but won't rub. I am using 1" thick MSA sway bars as an upgrade it it's a little tighter fit.

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More pictures, and a peak at using the STOCK e-brake setup, and a handy dandy bolt to holt it together. Yes it works.

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Now remember.. bleeder nipple is at its highest point. This is so the air can be bled out of the system!!

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Pretty huh?!

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I bled the crap out of the system, i was unfortunate and got alot of the air in the system as alot of my threads can attest to. I am not using a different proportioning valve, but it has a very nice balance. I'm happy. But don't give up!

I should prob take pics of the wheels and the rear brakes since it looks so damn good. LOL. Anyway.. questions?!

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Sufficiently different that general principles only apply. Regardless of that, good info and nice work.

A bit like the comment earlier in this thread that it isn't possible to weld to the axle housing because it's 'ductile iron'.

In reality a 240K has a pressed steel trailing arm that is welded together and there is no good reason why a new caliper bracket cannot be welded to it.

Welding isn't "verbotten anyway", it just has to be done by a qualified tradsman (or a better engineer is needed!!).

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The welding that is "verbotten" by the authorities, is on calliper brackets, which is what I was referring to at the time.

I think all States in OZ have a similar rule.

"Engineering" them is a way out but it is not cheap.

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