ABS on an S12
 

Is there any possible way I could put ABS on my S12?

And if so..... how? :D

The S13's came with ABS so might be worth looking for one being broken on SXOC.

I guess you'd need...

Wheel Speed sensors
ABS ECU (If it's even separate)
ABS Pump
Might need the Servo and Master Cylinder
A few lengths of Brake line and tools to make the ends up

God knows how you'd go about it but anythings possible if you've got the time and money :)

You would need the S13 front hubs and the S13 diff which has a sensor in it to get this to work. Or use an S14 system which I think has sensors on each rear driveshaft as opposed to the pinion shaft on the S13.

Again, why bother?

Hi Rich,
This is one of the mods I`m doing to my s12. But I did have a complete 200sx donor car to start with. The ABS module is located behind the 200`s rear quarter panel. As I`m transferring the complete wiring loom over into the s12, it shouldn`t be too difficult for me (I`m using a modified version of the 200 dash also). But to be honest, I think it would be too much hassle just to install the parts separately ;) .
Regards,
Ian.

Maybe install an airbag too? :1la

and traction control, furry dice and cup holders...LOL... :p

I guess it`s down to personal choice though. I will be driving the car in anger a lot and considering the amount of rain we get up North, it seems a sensible decision to me.

Plus I don`t know of any other s12 with ABS, so that`s a good reason in my eyes...LOL... ;) .

Regards,
Ian.

How will you do the sensors?

I haven`t had chance to weigh up the fronts yet Martin. But I`m planning on fitting the complete s13 rear subframe, diff, suspension, shafts etc complete. I`ve been measuring up the floor pan because I`m undecided yet wether to transfer this (from the back of the transmission tunnel to the boot slam panel) or just use the strut towers and subframe pick-up points. I know that the complete s13 rear axle is a little wider, but that doesn`t matter as I will be doing some extensive bodywork (including rear arch extensions and possibly even rear tubs).

Hope that all makes sense ;) . Plus I`m looking at coilovers all round too.

Regards,
Ian.

If you use S13 aftermarket coilovers you could use S13 front hubs and ABS gubbins.

The wiring shouldn't be that hard if you can get the diags from the S13 manual (think I've got a PDF one somewhere), certainly should be something an auto-electrician would cope with. Then you've just got to work out the bits under the bonnet.

You'd need the S13 master cylinder too. It's got just a F & R output as opposed to the F/R, F/L and R on the S12

Thanks Dan, but I`ve got a full PDF version of the s13 Service Manual. Plus I labelled all the loom as I disconnected it (as well as taking loads of notes) :D .

I`ve saved every single part from the s13 (including all fasteners and bolts...LOL...), so I know I have all the parts for the conversion already. I just need to make up a couple of new brake lines, which won`t be a problem, as I`ve got pipe flaring tools etc. Plus by using the complete s13 axle assembly, I can use the diff oil cooler that came off the car.

Sorry to hijack the thread Rich ;) .

Regards,
Ian.

I was kinda offering the Manual for Richards benefit as he'll need to make a separate loom up :)

Will an S13 MC bolt to an S12 Servo and work? Is there a difference because of the ABS? Have you compared the two Ian?

I'm pretty certain it will bolt on. If a big Z32 one bolts to my Datsun then it's likely an S13 will bolt to S12

Sound's like its do-able. A machine shop could probably attach S13 rear wheel speed sensors to the S12 output shafts... somehow :confused:

Sorry Dan, didn`t realise you were offering Rich the info....LOL...

I haven`t compared the servos side by side, but I do know that s12`s used the G32 or M32 servos whereas the s13 used the M195T servos. As Martin says the MC`s are totally different - the s12 has a bigger cylinder bore and different outlets.

I will compare the two servos next time I`m in the garage and post up the results :D.

Regards.
Ian.

Use a Z32 one, it's the biggest master cylinder of them all. I wouldn't worry about using this over the S13 one unless you're using Z32 calipers.

The wheels sensors are nothing more than a hall sensor on a toothed wheel. so you could make up new toothed wheels on the back of the front hubs and also on the prop.

There is an issue that you need to check on however, and thats whether the different diff ratio will cause an issue with the ABS, because the rear will be turning at a slightly wrong speed compared to the front.

Unless you use an S13 back of course, but this has difficulties in itself.

The only reason I was thinking that the S13 MC would be best is because it'll match the ABS pump.

Not sure how the S13 is set up for ABS at the rear but if it only runs 1 sensor on the prop then you might be in luck. As far as I can work out the ABS controller only looks for unusual deceleration, so slight differences in wheel speed front to rear shouldn't effect it.

Dan,
The rear sensor can be found once the prop is removed. It`s just behind the flange that connects the prop to the diff (so just one bolt to remove the flange) :D .

I wonder if you could rig up the set up that a lot of kit cars use for the speedo sensor on the front hubs, do you think that would work Martin?

I know that TVR`s use this type of idea.

Regards,
Ian.

for the love of god why??? s13 ABS is positively dangerous, the worst ABS system known to man. Best mod you' can do to any s13 is remove the
ABS

What makes it so bad? Is it one of those systems that jumps in and doesn't let you have the pedal back until the car is wearing with either a tree, wall or innocent bystander?

I`ve only driven a couple of s13`s and TBH I didn`t have a problem with the ABS systems. Both of them worked perfectly (in the wet).

I`ve checked the 2 servos side by side, the s12 servo is slightly larger in diameter, but the s13 one is deeper. The s13 servo fits into the bulkhead perfectly, but the s13 MC is a bit closer to the suspension turret than the silvia one. Plus the rod (that connects to the brake pedal) is a bit shorter on the s13. But I guess this can be altered on the adjuster to take up the difference.

I`ve not checked to see if the s13 MC will fit onto the s12 servo. But if anyone is thinking of this mod, it`s probably best to use the complete s13 servo and MC complete :D .

Regards,
Ian.

Don't see the need to use the servo.

Just use the master cylinder, it bolts on

I agree, you don't need the servo for the ABS so no need to swap.

Guess that tells me......LOL... :p .

But I guess it`s good to know that the s13 servo fits into the same bulkhead mounting, just in case someone is struggling to get hold off a s12 one ;) .

Regards,
Ian.

It's always good to know that there's something that will "just bolt on" :D

pedal sinks to the floor and doesn't recover easily if ABS engages. ABS ecu gets confused if you spin (on track for example) and gives you zero braking going backwards, and most of all it totally kills the pedal feel. The best thing I've ever done to s13 brakes is remove the ABS. I'd do it before changing calipers now.