[pyrohamish]

So what's the ideal brake setup for a sierra running oversize tires?
From what I can read;

Front
Vitara LWB front vented discs
Vitara LWB front calipers

Rear
Sierra front discs
Sierra front calipers

Master cylinder and booster is where I am confused.
Should I put a sierra booster on my early model sierra..all this does is make pushing the pedal easier
With a booster use the Subaru master cylinder swap
or
Run no booster and use which master cylinder to give increased performance?

[mrw82]

I'll let you know in a couple of weeks. I've got a 1 litre (standard disk front, drum rear, non boosted) and I'm putting rear disks on using the benT sierra kit (just waiting for it to be delivered). I plan on testing it with the standard front setup and booster. If proportioning is no good then I'll track down a vitara setup for the front.

At the moment I have no intentions of adding a booster or changing the master cylinder.

[mnemonix]

I ran for years with a 1.0 sierra (unboosted) with wt calipers/discs front and rear stopping 33" tyres.
The brakes worked just ok, but I had to nearly pick myself up out of the seat standing on the pedal for an emergency stop or to hold myself on a decent hill offroad. It also had a nasty habit of chewing a set of rear brake pads every 1000kms or so.

My stock WT I had at the same time was so much more pleasant to drive and felt like the brakes were stronger.

Upgrading to sierra brake booster and subaru master cylinder gives the car better breaking response than my daily driver, oodles of stopping power.
If I was to do it all over again, booster and master cylinder would be the first things I would add.

[pyrohamish]

Can I run a MC that is normally boosted eg. the GQ or Subaru as unboosted and just bolt it in and sort out the push rod parts?
Also what is the overall diameter, thickness and spacing off the firewall of the sierra booster?

[Gwagensteve]

Yes, you can use a boosted cylinder in an unbolted application. I do. You will need to re drill the mounting holes on the MC, open up the firewall hole and modify/fabricate a pushrod to suit.

The firewall of an early 1.0 sierra (metal dash) does not have adequate spacing between the steering column and MC to permit a booster to fit, so modification of the firewall is necessary.

I run LWB front callipers and rotors, sierra front calipers and rotors on the rear, and a 1 1/6" forester GT MC. I run 35's and it stops very well. Pedal effort is high(ish) but the pedal is high and hard with excellent feel.

I second that rear pad life is short. Not 1000km short, but short nonetheless.

If you are going to mod to take a booster, use a 2.0 vitara booster.

Steve.

[brando93]

dont mean to hijack the thread but why does it need to be lwb vitara discs? just coz theyre vented? im selling two sets of SWB vit discs and noone will touch them haha? just curious if they are different i.e. wont fit?

[Gwagensteve]

They will fit but they aren't really an upgrade over sierra, and the bleed screw is in the wrong spot. This isn't the end of the world, but there's no point dealing with it considering the brakes aren't really an upgrade.

The piston is much larger on the LWB brakes IIRC, as well as the venting. This also improves proportioning when using sierra callipers in the rear.

Steve.

[JrZook]

Gwagensteve wrote:

I second that rear pad life is short. Not 1000km short, but short nonetheless.

What's the reason behind this? I'm looking to upgrade but this doesn't sound like an advantage over the rear drums in terms of service life

[pyrohamish]

So whats the difference between the sierra booster and the 2.0L vitara booster?

[Fatzook]

pyrohamish wrote:

So whats the difference between the sierra booster and the 2.0L vitara booster?

Dimensions mainly. And the master cylinder is a larger bore IIRC.

[KEENSY85]

Could u get a wt booster and cylinder and drill some holes in the firewall and cut the large hole out.and disk and roars off a wt all round (derek at suzi sport in lawnton on the north side of Brisbane for $300 to run front disk breaks on the rear

[pyrohamish]

How about a Vitara 1.6 LWB booster...would this bolt up to the subaru/gq master cylinder?

[christover1]

JrZook wrote:

Gwagensteve wrote:

I second that rear pad life is short. Not 1000km short, but short nonetheless.

What's the reason behind this? I'm looking to upgrade but this doesn't sound like an advantage over the rear drums in terms of service life

I don't know about 1.3 masters.
But my 1.0 master had a valve in the rear brakes, where line comes out of master.
Removing that valve lead to much longer rear pad life.
Never changed them again after that.
It is to do with drum brakes needed residual pressure to work.
Not needed for the discs.

I think the 1.3 has a 3 way cross over system with a bias valve, not sure if same thing exists.

[Joshyboy26]

Grave dig!

I have a 86 tray back sierra

I cut the firewall and booster etc out of an 89 swb.

I tentatively plan to stitch them together to get boosted brakes.

Will/ could this work?

what model Subaru mc bolts to the sierra booster is it the Forester Turbo Master Cylinder (1 1/16" bore)?


cheers!

[Gwagensteve]

Yes. That's should work fine with a booster.

[Joshyboy26]

I also picked up a late 90's Subaru Legacy / Imprezza Brake Master Cylinder (with ABS). Its a 1 1/16" diameter, compared to the stock sami master cylinder which is 7/8" bore - it should power the vented toyota brakes with chevy rears quite nicely. This master cylinder is basically a bolt-on. It has the same mounting hole pattern, has metric fittings, and similiar sealing surface to the booster and a low level reservior switch. The only tweak that needs to be done is the sami plunger needs to be lengthed 14mm out to a total length of 82mm....



Just found this on pirate.

Has anyone put a booster onto a non boosted cab?

[dank]

I used the same master in my zook on the 1.3 booster Josh and it was a ton better pedal feel and it braked very well with the sierra rear calipers all round but it needed more bias to the front...but that could have been that I had the lines at the master around the wrong way???...never checked....took me back to my bike riding days as a kid...rear wheel skids everywhere

[Joshyboy26]

haha Yay skids!

ok cool,

so now I guess ill got and do some measurements and see if I can jam I booster into this thing.

With luxy brakes and no booster I reckon it might be a bit of a handful

[Gwagensteve]

I'm sure it would be fine. Remember almost no race cars run boosted brakes. A booster does not improve brake performance- it only lowers effort.

The boosted firewall swap has been done before, but I think you'll also need the 1.3 pedal box and maybe the dash as the relationship between the dash hardware and pedal box is different between the two cars.

[Joshyboy26]

I just had a look I think the firewall is the same shape, it would just be the pedal box bolting back to the dash, as you said.

I do have the pedal box as well so its possible

ultimately it depends on what the engineer says I guess.