Sti Master Brake cylinder swap Qs

I have had some MAJOR problems following my STI MC/ BB swap. After running the car for a while, the brakes are locking up in all four corners to the point that I am running at 3000 rpm just to go 10mph and all four corners were smoking hot. After the brakes cool down, all is good again until the next time I travel, happens after about 5 miles or so. Unfortunately it happened on I-95 in downtown Providence last week and the car became essentially uncontrollable. I've bled all four corners and the MC but I suspect it is a problem with the MC. Perhaps it is because I am using an STI manual transmission MC with an AT Legacy. I'm hoping I can remedy my problem with a brand new WRX automatic transmission MC. Anyone have any ideas why all four brakes are locking up now when hot?? Would an ineffectively bled MC cause this?

I just got done installing all of my stuff. I am having the exact same issue as you. If you found a resolution and if anyone has any further input please post up. With out a doubt its not the check valve, its orientation, or a bleed needed. According to test i read online, pumping the brake with the car off to remove residual booster pressure(makeing the pedal hard), then putting pressure on the brake and cranking the car up the pedal gets softer with pressure remaining on the brake pedal. My booster passed that test, so i dont think its the booster.

But i will say, DAMN the pedal is so much nicer. A pad change and fluid bleed couldnt touch this kind of pedal improvement in its wildest dreams.

Update, the rod coming out of the booster was to long and needed to be adjusted down some. This rod attaches the brake pedal to the booster. If its to long its leaves some constant pressure on the master which builds up pressure in the brake lines as you use them. Just needed to adjust it to be shorter to relieve that pressure. I didnt compare rod length of oem booster vs sti booster, in hind site i probably should have.

You dont have to be exact with this length fyi. If its to long, you will get the same symptoms i had, if its to short you will have some initial slop in your brake pedal(still nothing as bad as the OEM setup)

Great...another mod I need to add to the list.

Ever since I picked up my '05 LGT Wagon a few months ago, one of the weakest points to me on the car has been the brakes and their "feel" (or lack there-of). My other car is a AC Schnitzer Widebodied E36 M3 that has a Brembo GT BBK and that thing has amazing stopping power and feel. Makes the LGT feel like trying to stop a schoolbus in comparison.

If the STi MC and Booster will improve the responsiveness and feel of the brake pedal then that's definitely something i'll have to look into adding to my LGT. Thanks a lot to those that pioneered this swap!

I spent $80 total for my STI master and booster. From the driver seat, it literally feels like im driving with an OEM set of Brembos from a STI. The brakes engage almost instantly, with a progressive and responsive bite curve, pedal pressure has also increased greatly improveing the ability to feel the brakes and brake precisely.

For 99% of the LGT'ers, they wont care bc in the end they are driving a family car that they may have a few mods done to it for fun. For any real car enthusiast, this is one of those cheap mods that you simply cant find any bigger bang for buck for a brake mod.

Get rid of your stock pads first. They suck.

I'll probably wait until after I switch the BB & MC so I can make an honest comparison, but pads/rotors and caliper rebuilds are definitely on my list of things for the summer. I'll spend some time between now and then figuring out which ones to use.

Cheapest I see on eBay is $90 shipped http://www.ebay.com/itm/2004-SUBARU-IMPREZA-WRX-STI-OEM-BRAKE-MASTER-BOOSTER-EJ257-GD7-/290644124056?pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr&hash=item43abbd6198

car-part.com is probably cheaper...

Eddie you still doing the lgt thing or have you since moved on?

Hey Swine, still got the lgt but probably going to sell it soon.

Hey Swine, still got the lgt but probably going to sell it soon.

What's your next car(s)?

My STI MC&BB came in today. It's going to sit in the shed until spring, but I got the brake booster, master cylinder, and the vacuum hose with check valve from ebay seller silverlineparts here: http://www.ebay.ca/itm/370282909074?ru=http%3A%2F%2Fwww.ebay.ca%3A80%2Fsch%2Fi.html%3F_from%3DR40%26_trksid%3Dp4712.m570.l1313%26_nkw%3D370282909074%26_sacat%3DSee-All-Categories%26_fvi%3D1&_rdc=1#ht_1080wt_290 (No affiliation, just a happy buyer)

I'm looking forward to installing it and feeling the improvement!

Dude, replace the stock pads first, PERIOD.

dude, dont waste your time doing one or the other and do it all at once, PERIOD.

Funny guy, huh?

You're right, that'll have the greatest benefit, but he's still on his stock pads, and he said he's curious about the difference it'll make. Easy swap of the pads will satisfy his curiosity about how shitty the stock Hitachi pads are.

Bumping a thread from the dead.

Has anyone installed the STI Brake MC and booster into a VDC equipped car?

Bumping a thread from the dead.

 

Has anyone installed the STI Brake MC and booster into a VDC equipped car?

Yeah already done on a 3g WRX, which from the brake booster/MC perspective is the same as a VDC equipped Legacy.

Follow Monkiboy's adventure here: http://www.3gwrx.com/forum/index.php/topic,20410

cliffs notes: It ain't easy.

Yea, I saw that after I posted. Thanks.

Looks like a PITA. I'll double check the flare size on my 09. Maybe, by some dumb luck, I'll have the 10mm flare fitting. Doubtful.

Maybe I'll take the plunge to swap it over if the pedal feel bothers me that much. Stupid VDC. Ooo, maybe the NEWER STi booster/BMC will directly swap? They had VDC too.

Yeah pretty sure the VDC cars all have the larger lines and fittings.

STI has the same 15/16 MC. If there was a bigger MC in the late style bolt pattern I and many others would have been all over it already!!

There is a 1-1/16 VDC master cylinder, from the 00-04 H6 VDC Outback. The only problem is that one of the ports is in a different place and it still requires the older style booster. Also the pushrod part seems different:

http://jamalb.net/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=2777&g2_serialNumber=1http://jamalb.net/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=2779&g2_serialNumber=1

Nissans use an external check valve for the booster and they come with the cosworth intake manifolds. I think part 47478-04F03 will work.

As far as bleeding goes, you should really, really, really bench bleed the MC before installation.