Right chaps I'm having a real headache here I could use some help with.

Ok starting from the top, brake pedal has felt horrid since I got the car. Lots of travel, no feel or bite and it's really soft. Obviously first thing the brakes have been bled over and over, not a hint of air bubbles.
Pads all round changed with new pins and fittings etc, calipers cleaned thoroughly and greased up, also had a set of discs on the front, didn't help.

So then fitted some braided lines and rebled again, still didn't help. I had a similar problem with my old megane 225 brembos and rebuilding the calipers worked a treat so I've just had the front calipers off, inspected pistons and rebuilt with new seals and dust covers. Once again bled and no air. Nothing has changed the brakes are still crap!

Our Evo 9 has pretty much similar brake setup as our STI and the brakes on that are sharp as a knife, all you have to do is breathe on them and you'll go through the windscreen but the scoobies are borderline dangerous when pressing on.

Where do i go from here? I'm considering rebuilding the rear calipers but before I spend the money want to make sure I'm not missing anything or common faults?

Cars an 04 Sti with gold calipers. Thanks.

 

You seem to have done everything else so only leaves brake master cylinder or servo.

 

Are rear calipers not prone to fault or did I imagine reading that recently?

It feels asthough the first half of pedal travel is spent expanding the pistons out of the calipers, as if they are being pulled right back in after every application?

 

The rears tend to corrode and stick , usually caused by lack of use rather than actual " faults"

 

have the same fault on my front brakes. Im tending to think its the master cylinder

 

Hmm I would have thought a seized caliper would give a former feel than a soggy pedal with longggggg travel.

Both rear discs are sweeping clean and the pads weren't wearing in any irregular fashion.

 

Have you got to agree with Tony but you may want to get the ABS checked.
Sadly, I do not know how but I am sure that the braking rigs at an MOT station should throw up any faults.

The rear brakes do not provide as much braking as the fronts and would question if they where at fault but they may require a good bleed through as well.

Just a quick question, what fluid are you?

 

Thought the ABS would only come into play if traction or grip was lost and then it make itself known by modulating rapidly , but this hasnt happened or been mentioned by the op, Does the handbrake need adjusting ? And,as has been mentioned, what fluid was used and when was it last changed ?

 

True air could be in the abs pump but I've got the pump operating on wet surfaces to purge any air into the lines.

Handbrake is high but they're internal hub acting on these like the Evos? If so shouldn't affect calipers.

Dot 4 fluid used.

 

What you say about the handbrake mech self adjusting is correct, up to a point. If the mechanism is sticking inside the drum , they wont adjust. Id at least , look at the mechanism and check movement . Then adjust the cable .

 

So, air got into the ABS pump i assume , when you added the new fluid? So , even though you said you had bled the brake calipers, air is still present in the system . It doesnt matter where the air is , in the pipes, the pump or the calipers , all the air must be got rid of if you want a better feel on the pedal. I dont think your method of activating the ABS will work either. Air in the pipes have nowhere to purge to , even with the ABS modulating as your doing. It may be worth buying a pressure bleeding kit that should push out all the air . Or , give a man some cash, and get it done professionally

 

All the pressure bleeders on the market don't have an adaptor that fits the poxy scooby reservoir

 

Easily fixed by using one off a brake master cylinder off a scooby

 

I don't think you will ever get a comparable feel to your evo with the standard master cylinder. I am on my third Subaru and despite fitting AP's and braided lines on the last two they never feel as good as other cars in terms of feel. It will stand on its nose if you stamp on the pedal but the 'feel' is never as good as my other cars (Renault, Peugeot, Audi, Vauxhalls to name a few). I don't know why it's frustrating.

That said you obviously have something more serious going on if your brakes feel dangerous.

 

If you cant get a cap to fit , it might be advisable to see a brake specialist to sort it

 

Did you sort this problem ?

 

Very odd problem hope you get it sorted.

 

I have the exact same problem tbh, all bleed properly new discs,pads,fluid,as said evo brakes are exactly the same yet perform much better! Are evo master cylinders different to the impreza's?

 

It will be down to the servo. The Evo servo will provide more assistance, the Scooby less.

From my experience modern cars are massively over-servo'd. They seem like an on/off switch. Light braking or full lock up. Not much in between. The Scooby gives you far more modulation of the pedal. This does mean though that you have to press much harder to full engage them.