Well, I got a 94 2door trackick...and since i put the 31s on my braking just got a little worse.  Now do I need EVERYTHING off the 4 door such as calipers, pads, rotors, wheel cylinders, shoes, and drums?

I have replaced mine front simple disks of my 2dr sidekick, with the vented disks of a 4dr one, and the increase was significant. All you need for this is the calipers, the rotors and the pads.

Beware that if you install the brakes from a 16" rim sidekick model, you will propably need also 16" rims.

If you also go to 16" rims, install the front and rear brakes of a 4dr, 2 or 2.6 lt, or XL7 even better!!!

Yes, and the front caliper mount's also I was told, have not messed with mine yet but will be trying it out on a sammie when I get a chance(just the front's). you might get the rear backing plates also,the rear brakes are huge.

So i need front calipers, caliper brackets, rotors and shoes?  Is it complete bolt on?  Do I need to worry about the back?

So i need front calipers, caliper brackets, rotors and shoes?  Is it complete bolt on?  Do I need to worry about the back?

Yes, except for the shoes, you need pads It is bolt on, but you'll need to bleed your brakes. You don't need to do the rear, but you can if you like. The rotors are not bigger in diameter, they're actually a bit smaller... but they're vented and stay cool. For rotors and pads, you should really get new, and the calipers you might find used in a salvage yard for much less money.

I've done this on mine, the disc diameter were the same. The big difference is that the 4dr pistons are around 20% bigger in area. I fitted the 4dr rears as well to maintain the braking balance. Its a pretty simple swap but you need the park brake cables too. The bonus is that the cables are longer so you have more slack. The stock cables can be too short if you have long travel shocks causing the park brake to be pulled on when the wheel drops to its full extent.
The master cylinders vary in size, I can't remember the exact sizes but if you have the smaller master cylinder then you should fit the 4dr m/c too.

I've done this on mine, the disc diameter were the same. The big difference is that the 4dr pistons are around 20% bigger in area. I fitted the 4dr rears as well to maintain the braking balance. Its a pretty simple swap but you need the park brake cables too. The bonus is that the cables are longer so you have more slack. The stock cables can be too short if you have long travel shocks causing the park brake to be pulled on when the wheel drops to its full extent.
The master cylinders vary in size, I can't remember the exact sizes but if you have the smaller master cylinder then you should fit the 4dr m/c too.

x2

-Eric

I think I'll go the easier and cheaper route and just do the front with the calipers, brackets, rotors, and pads...it'll have to make some kind off difference

I think I'll go the easier and cheaper route and just do the front with the calipers, brackets, rotors, and pads...it'll have to make some kind off difference

and later down the road when you get more cash you could do the rear

Man why didn't I get as good of a reply when I asked about the same question? So I've moved to '93 4dr (new) callipers & pads on my 90 2dr with stock rotors. I have installed them today and will bleed them tomoro and see how much improvement there is. I would have them bled already but I've been running a few projects this week.              NMc

What about disc brakes for the rear?  What's involve. 

Rear discs are much more complicated to fit, they need custom mounting brackets, pipework etc.. I had Ford calipers with Sammy discs on mine. The Park brake didn't work properly because of the wrong leverage ratios between the lever and the caliper. I also had excessive pedal travel which I believe was due to the extra fluid required by the rear calipers. Disc/disc and disc/drum master cylinders are different internally. One day I may have another go at sorting it out but for now I just want brakes that work so I've fitted the LWB drums.

Callipers generally require less fluid trasnfer than drum brake cylinders. Disc/drum set ups do have a check valve to maintain a slight pressure (4-6psi) on the shoes however which would need to go as pads should not drag. Some master cylinders are designed to have the pads pull away just slightly to increase fuel econmy but those have what is called a stepped or quick take up bore to feed more fluid before presure builds. Disc/drum set ups also have a hold off valve which keeps the front pads from engaging untill the rear pads have made contact. Food for thought.                                   NMc

Do the Grand Vitara or XL7 have rear disc brakes on any models?

Callipers generally require less fluid trasnfer than drum brake cylinders.

I have heard this but if you measure the areas of the pistons and then calculate the volume a caliper takes more fluid. Supposedly a caliper requires less pressure which should even things out a little. However comparing the insides of an otherwise identical m/c the disc/disc version pushed out around twice the fluid.

Disc/drum set ups do have a check valve to maintain a slight pressure (4-6psi) on the shoes however which would need to go as pads should not drag.

This is built into the m/c on the Zuk.

Disc/drum set ups also have a hold off valve which keeps the front pads from engaging untill the rear pads have made contact.

The Zuk m/c is a tandem design, there are two pistons in line. The rearmost operates the rear brakes, the brake lever presses the rear piston in, operating the rear brakes. The pressure in the rear circuit builds and that pushes the front piston forwards operating the front brakes. Therein lies the problem, if the rear brakes take too much fluid the pedal is much nearer the floor before the fronts start to operate and, with the Ford calipers, you run out of travel before you get full braking.

Food for thought.

Definately. I'm sure that it can be made to work but it needs to be well thought out and it might need some experimentation to get it working to its full efficiency. I'm going to give it another go at some time but for now I just want to get the vehicle through its inspection and use it.


There is another variable too which should be given some thought. If the vehicle is higher than stock and/or more softly sprung then there is likely to be more weight transfer to the front under braking requiring more forward brake bias. With the earlier load adjusting rear brakes this could be easily tweaked out.