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2000 2.5 RS Impreza 4 door
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Discussion Starter · #1 ·
Yesterday I just got done installing a ABS SVX MC (1-1/16" bore) and single stage brake booster. The install went fairly well and seemed a bit easier than I thought it was going to be. So I bled the brakes with the proper Subaru pattern (RF, LR, LF, RR)> I started the car and to see how it felt and it still goes down 1-1/2"-2" before any braking like before. :mad: I definately feels different when you get to the braking point but the main reason I did this was to shorten the distance to the intial braking point. So just in case I went around again in the correct order and it still feels the same. :sad:

Is there any way air could be trapped in the ABS unit or somewhere in the brake lines to where I couldnt get it out with normal bleeding? Do you think a shop or dealership would have the tools to correct it or am I just screwed?
 

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Premium Member
overdeveloped beater
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8,335 Posts
I wonder the same thing. The MC has to be "bench bled" prior to bleeding the wheel cylinders.
 

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impreza base!
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780 Posts
yah you need to bench bleed the master cylinder, but I really don't know if it'll get any better than that. its a much bigger upgrade for impreza's with the 15/16th master cylidner. your car your only going 1/16th bigger.
 

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99 Impreza 2.5RS Black
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613 Posts
On my RS I went from stock to the following:

- Stock WRX setup in front
- Stock RS setup in rear
- '95 Impreza L Single Stage Booster
- 1 1/16" bore MC (unknown year)
- Stoptech SS lines
- Axis Ultimates pads front & rear
- Super Blue fluid
- Speedbleeders

Brake performance and feel increased tremendously, granted I was at about 60k on the original pads and rotors ;) But with my setup, I could easily lock 'em up before the ABS kicked in on pavement and the pedal feel was awesome.
 

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2000 BRP Subaru Impreza 2.5RS
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470 Posts
if you didnt bench bleed the MC, do that. If you did, you could try adjusting the brake pedal to get rid of the free portion of the throw.
 

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98 Red L 2.2L 5spd
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343 Posts
yeah bench bleeding is a must. if your car has abs and you didnt bench bleed you might be in some big doo doo. cuz the abs units hate air
 

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White 05 RS Sport Pkg
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1,434 Posts
Damn dude hate to hear you're having problems, I remember when we were talking about that upgrade... Hopefully everything goes better for you!
 

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95 L, 96 OUTBACK
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2,918 Posts
When you say play to the inital brake point is it squishy then it gets hard? If so my brothers outback does the same thing.
 

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Wagon Mafia
2002 WRX Wagon PSM
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1,748 Posts
Another thing to try besides the bench bleeding if you didnt do that yet is bleed the brakes in order from farthest from the master cylinder to the closest. We always did it this way when I worked at Subaru. This way you get all the air from the lines futher away first. So the order would be RR, LR, RF, LF instead of how you did it.
 

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93 Teal Unicorn!!!
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392 Posts
yea what he said ^^^^ your supposed to bleed the furthest away from the abs unit first. . . . try that and bench bleeding, those should help with the squishy evil pedal
 

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2000 2.5 RS Impreza 4 door
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3,408 Posts
Discussion Starter · #12 ·
Yep definately didnt bench bleed. :bonk: From what I have read all you do is uninstall the MC, keep it level with a vice, plug the port holes and compess the plunger thing until there are no air bubbles. Is that right? What are the chances it stays the same after I bench bleed? :( Ill stick with the Subaru recoomended pattern though.
 

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overdeveloped beater
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Instead of plugging the ports, make some looped lines that run from the ports to the resevoir. Nothing fancy....just make sure the ends are submerged in the fluid. Plugging the ports will ensure nothing is bled, as it has nowhere to go.
Yep definately didnt bench bleed. :bonk: From what I have read all you do is uninstall the MC, keep it level with a vice, plug the port holes and compess the plunger thing until there are no air bubbles. Is that right? What are the chances it stays the same after I bench bleed? :( Ill stick with the Subaru recoomended pattern though.
 

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2000 2.5 RS Impreza 4 door
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Discussion Starter · #15 · (Edited)
Can I just disconnect the 2 steel brake lines, and put on the hoses while the master cylinder is on the car? Then I could use the brake pedal with push the plunger thingy.

Also, once you get all the bubbles out do you just unscrew the hoses and put the brake lines back on? Can air get in the MC in between these steps?
 

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99 WRB GC V9 Spec C RA recce
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990 Posts
The booster pin might sit too far from the inner cylinder of the MC, meaning you have to push the pedal for the pin to reach the cylinder initially, and only then it starts pushing it - hence your free pedal travel.

to illustrate it:

booster _____ mc
{}------> ______ ---[]

see the empty space between them? that's your problem.
you can adjust the pin at the front and thread on the back of booster to make the pin sit tight against the MC cylinder

take eveything out, compare it with your previous setup to see how it's supposed to sit/fit and adjust accordingly

bench bleed is also a good idea
 

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overdeveloped beater
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Yes, you can do it on the car, it sits pretty level, so it shouldn't be a problem. Go slow with the pedal stroke and make sure you make a full stroke.

Once done, undo the fittings and reattach the brake lines. The fluid wont drain out. You will want to re bleed the wheels though, to get any air caught in the fittings out.
Can I just disconnect the 2 steel brake lines, and put on the hoses while the master cylinder is on the car? Then I could use the brake pedal with push the plunger thingy.

Also, once you get all the bubbles out do you just unscrew the hoses and put the brake lines back on? Can air get in the MC in between these steps?
Also check the assembly like Hyper suggested. This will ensure you've covered all the bases and will narrow down any further troubleshooting(if needed).
 

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2000 2.5 RS Impreza 4 door
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Discussion Starter · #18 ·
Well I bench bled the master cylinder, now it feels better than before. I like the feel of the pedal under braking compared to the old MC and dual stage booster but the intial braking point is still too far for my liking.

What I plan on doing tommorow is taking out the pin that attaches the fork thing (in the pic below) to the brake pedal and unscrewing it so it is futher away from the master cylinder. That way it is like it is already pushed in a little bit from this setup. I think that is what you guys were saying but just making sure. I couldnt tell whether the pin that pushes the MC Hyper was talking about had free play and I didnt see an adjustment on the master cylinder side of the booster so I assume you are talking about the fork right?



In the instructions I was reading it sounded like NorthUrsalia was saying make sure you have the fork is a similiar position to the old setup or the brake light may come on too early (like w/o pressing the pedal) or too late. But I was told that there is another switch that controls when the brake light comes on. :confused:
 

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needs more cowbell
95L, 07 2.5i, R6
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+1 on bleeding at every wheel. You probably have air in one or more calipers
 

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overdeveloped beater
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Yeah, move that clevis out a little bit and see if your pedal feel improves. I need to do this on mine too....
 
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