4 wheel disc brake change over

[Synlubes]

I`ve read here that 300ZX(Z31)frt hubs/rotors can be use on frt of early Z,or use early Z hubs and the 300ZX(Z31)frt rotors with 1/2 spacer? what is used for the rear to get the same bolt pattren?

Can the rear stub axles from a 300ZX(Z31)be used in rear of an early Z? Are the rear rotors on a 300ZX(Z31)solid or vented? Working with 5 lug change over.

[zcarnut]

What most people do is to re-drill the rear stub axle wheel mounting flange surface for the five bolt wheel pattern. Go to http://zcar.netdojo.com/5lug.htm

 

The Z31 rear stub axles have a smaller (both OD and ID) inner wheel bearing and a larger (again, both OD and ID) outer bearing than the Z’s or the ZX’s. Hence, the stub axle tapers out, unlike the earlier Z cars which have similar sized inner and outer rear wheel bearings and a constant diameter shaft.

 

You could probably handle the inner bearing problem by using the earlier inner bearing with a suitable “collar” as a spacer, but the Z31 outer bearing is the real problem. Yes, you could machine down the diameter of the Z31 stub axle shaft and then use the earlier outer bearing. But you should then follow with the correct heat treatment operation. Unless you _really_ know what you are doing, this is risky, in my opinion.

 

Too bad, as the Z31 stub axle is larger in diameter where the wheel flange is welded, and this is a stressed area, as noted by the failures experienced by some ITS racers.

[Synlubes]

Thanks ZCarNut,

The link and info surely answered some ?s! The pics of the 5 lug stub axel showed a couple of the lug holes drilled very close to the edge, The car will be used for on track events! Is this a tryed and true set up? Any racers out there use is set up?

Thanks, Doug

[Guest Anonymous]

Doug, let me know if you plan to do this. I would like to see the actual process.

[stony]

im thinking someone out there has to make a bearing with the OD for the s30 and the ID of the z31 for both the inner and outer bearings. If you could find a bearing setup like this, the stub shafts should work which would also allow the use of the z31 cv axles as a bolt in option with r-200???? any comments?

 

Its kinda hard to see in this picture but the bearing surfaces are pretty much in the same area

 

and with everything kinda in place looks like it will work

 

before i go any further has any one tried this ? Ill let you guys know how it goes. If everything goes as planned will have 88 z31 turbo brakes all around and cv axle and newer r-200 from same car ;>

 

In the above pics all the hardware is kinda just laying in the hole and will go in at least and inch or so once everything is pressed

[randy 77zt]

goto a bearing supply house and get a few catalogs.then measure your parts and read.you might get lucky

[Guest scca]

i tried that a year ago and couldnt find it

[stony]

Well your right no bearing for a striaght out swap available. Next option is to machine a sleeve for the smaller OD of the inboard 300z bearing and bore out the ID of the strut housing to fit the OD of the outboard 300Z bearing. Anybody tried this? anybody think it will work/not work? Id really like some input on this because if i try it and it dosnt work ill need some new strut housings ;<

 

thanks

 

guys

 

[jeromio]

That be a beefy stub.

 

I would try using the stock Z31 bearing and mod the housing. My logic being that machining the one part is cheaper and also bearings are wear items, housings are not.

[stony]

Well the housing are at the machinist getting fitted with 300z bearing. getting the housing enlarged on the outbd side and a collar pressed in for the inbd bearing. the next obstacle will be the cv axle length and making caliper brakets ;>

If this works i will invest in a set of really strong race axles $$$$$ and see what happens.

[stony]

ok the machining is done and everything is being pressed together after the new longer studs are installed. instead of going with the 300z bearings we went with tapered roller bearing. the housing was machined out and races installed. once i get the housings back ill need to see what length the axles will need to be and then on to the brakes. with any luck this will cure my breakage problems.

[Doug71zt]

Hey Stony - That's an interesting way around the problem. How are you going to get the clamp-up on the drive splines without overloading the tapered bearing? Are you going to leave the spacer between the bearings? Thanks for keeping us posted on this - it may be something I'll do if it works out for you.

 

Doug

[Mike C]

I was curious about that as well. The 63-82 Corvettes use the tapered roller bearings on the drive spindles. They use a special tool to setup bearing pre-load. They are also failure prone and the reason most manufacturers use caged ball bearings like the OEM Nissan setup (same as my wife's 325is also.)

[GLENN280ZX]

I Know I'm A Little Late Here But I Just Found This. I Have Used 300 Axles. The Bearings Are Not The Problem, They Will Inter-change. There Are Narrow And There Are Wide. Dia. Are The Same As 280zx Inner And Outer. The Only Dif. Is Outer Insde Due To Taper, But They Still Swap. You Must Use The 300 Brg. Spacer, Due To Taper. It To Is The Same Thick-ness As The 280. Even The Comp. Fange Is A Swap For The 280 Cv. Buttttttttt The The 300 Is About 2 Inches Wider Than The 280 (the Rear Susp.) That Makes The 280 Cv About 1in..100 To Long. I Know I Have Been Chacing This For 2months. If The 300 Flange Can Be Sectioned And Welded Back, Can This Handle Any Kind Of Crediable Hp? I Dont Know, But I Am Doing It Next Week. Oh Yea There Are Three Diff. 300 Flanges One Is The Big Cv With 4 Bolts, One With Gold Dust Flange And The Shortest Is The One With Black Dust Flange. This Is The One That I Tried First, I Am Going To Cut A Long One (gold Flange) And Tig It Back Together. If This Looks Good Than I Will Move To The Caliper Mount Which Is Not Much More Than Just A 4 Hole Brkt. To Mve The Cal. Out. The Front Is Not So Bad Exceptttt Hud Moves Wheel Outside Of Car 7/8 In. Cant Use 300 Strut Cause Spindle Is Moved 1in. Forward In Fender Ie It Is Not In Center Of Sturt Like 280.i Hope This Helps. Any Just Ask. Cause I Am Doing Or Have Done It.

[Synlubes]

Thanks GLENN280ZX and welcome.

Are you doing this mod to an s30 or s130?

Please post your documentation, pics and results.

[GLENN280ZX]

I Dont Know Body Series, But The Car Is An '80 280zx. I Rechecked All Parts This Week-end And Found That The Black Dust Flange Is The Same Hights And Depths As The 280 Turbo Cv Flanges. I Still Have Not Figured Out Why My Cv Axle Didnt Fit In. May-be Because A-arm Hanging To Low On Jack-stand. But Give Me A Couple Of Days(i Work Long Hours) And I Will Have The Rear Figured Out.