Member Profile: HyRax

[HyRax]

Thanks guys!

Mark, by comparison, your adapters perfectly fit my brother's Impreza RS to complete his WRX caliper conversion perfectly first time. Awesome.

Also - are you using a brake master cylinder stopper?

I actually forgot about that, so I'll be getting one before I set about putting the MBC on.

[cruisn]

Mark, by comparison, your adapters perfectly fit my brother's Impreza RS to complete his WRX caliper conversion perfectly first time. Awesome.

Thats good to hear Jeff.

[bigBADbenny]

Also - are you using a brake master cylinder stopper?

I actually forgot about that, so I'll be getting one before I set about putting the MBC on.

Just asking - sounds like a huge improvement already!

[3rspecb]

Great job and enjoy your new brakes..

[HyRax]

Today I got the MY05 STi Brake Booster and Master Brake Cylinder installed. The extra pedal firmness (some 13%) feels amazing compared to the stock setup and as a result, my brakes are now even touchier than they were before!


Click on the image for full size!

What is interesting to note is that the tyres are squealing a bit more than before under ABS-driven heavy braking, suggesting that the stock BB and MBC really weren't working the Brembo's has hard as they could go. Makes sense given that the bore of the STi MBC is a good deal larger than the stock unit, pushing more brake fluid to the calipers.

The BB and MBC fit without any issues inside the engine bay - a perfect fit with no further modification required, however it was a slightly different story inside the cabin.

The only issue seen during installation was the length of the Brake Booster rod - it was too long. The stock unit is 136.5mm in length from the body of the brake booster to the cotter pin hole on the rod. The closest we could adjust the STi brake booster's rod length to was a hair over 137mm. Not a big deal, right? Sadly, while I'm getting 13% improvement in braking firmness, it also translates into an apparent 13% raised brake pedal and locked brakes!


Click on the image for full size!

The obvious solution here is to trim/grind the rod so that we can make it shorter, but the mechanic who did the work for me simply adjusted the upper stopping point of the pedal to prevent the brakes locking up (because the pedal was effectively being lightly depressed all the time). Have done several test drives now and it's working like a charm and the extra height of the pedal doesn't take long to get used to either. Brake lights still operate as expected as well.

While they worked on that, I also set about adjusting my hand brake in the cabin as the new larger handbrake shoes from the Brembo upgrade had provided a lot of extra slack in the handbrake cable (despite re-adjusting the handbrake adjuster on the rear hubs), making for a very high bite point on the handbrake lever. It now bites hard at about 4 notches instead of the previous 20 or so.

Next thing to get to complete the brakes is a Master Cylinder Brace. I didn't get around to ordering one before today's install, so I'll do that later. Needless to say, the firewall flex is very noticable from looking in the engine bay while someone else pushes the pedal, so definitely need the brace to eliminate that.

[Corsair]

Glad you got it sorted. Your stopping power must be much improved!

[HyRax]

Absolutely. The stock brakes completely pale in comparison to the Brembo's as you'd expect, and the new BB and MBC are now applying a little more force to the brakes that the stock BB and MBC couldn't do (not a lot, but it translates to a big physical difference in the feel of the pedal).

I'm yet to re-measure 80kph to zero stopping distance again to see if there is any measurable difference to the stock BB and MBC, but I'll probably do that over the weekend.

I'm still wondering what exactly it was that your mechanic felt/found that the GTB BB would not fit in your car.

[Corsair]

I'm still wondering what exactly it was that your mechanic felt/found that the GTB BB would not fit in your car.

Wasn't fully articulated at the time, but I guess it could have been the length of the Brake Booster rod as you mentioned above. Thanks to the braided lines though, my pedal feels much better now anyway.

BTW, care to share which sway bar grease you are using? I'm getting squeaks from the rear when I go over speed humps.

[HyRax]

BTW, care to share which sway bar grease you are using? I'm getting squeaks from the rear when I go over speed humps.

I've tried a few different greases, including some marine-grade grease to see if it outlasts rain better, but have recently gone back to regular all-purpose grease again (which looks army-green/brown/black in colour). It performs about the same IMO and costs a lot less.

One of the key things you should do with your own swaybars is to get some rough sandpaper and remove the paint off the contact area of the bushes (all the way around the swaybar). The reason for this is that those bushes are specifically made for a specific size of swaybar and the paint adds about 1-2mm of thickness to the bar. As a result, you effectively squeeze all the grease out and the bushes don't slide as well on paint as it does a clean metal surface. Sand the bars and your grease will stay there longer and slide better.

Regreasing after heavy rain or dirt driving still applies, however.

[rooby]

I've been using penrite moly grease and it's been fine. Castrol lmm is another or tat should be good.
Look for ones with molybdenum disulphide.

[Corsair]

Thanks for the tips fellas. I'll look into Rooby's grease and sanding the bushes.

[xyz]

Do you know if there's any difference between the GT brake booster and master brake cylinder vs STi brake booster and master brake cylinder?

[HyRax]

Do you know if there's any difference between the GT brake booster and master brake cylinder vs STi brake booster and master brake cylinder?

The booster is not very different (if at all) - it's all about the Master Brake Cylinder itself. The STi sports a bore 17/16" in size (the largest of all Subaru's) while the bore in other Subaru's vary, but are generally 15/16" in size (and some Subaru's are even 11/16" in size). This means the cylinder can hold more brake fluid and thus pump more of it to the brake calipers (13% more in fact).

The reason you also need to marry an STi booster when doing an MBC upgrade is that the mount to the booster is different (horizontal instead of on a 45 degree angle).

[chanham]

awesome mods man! your really milking the 2.5 for every bit! sweet!

[HyRax]

Thanks! More to come as time (and money) permit!