Need help with WRX Fronts, Arrggg.....

[skid542]

So as many you probably know, I recently upgraded my brakes to 316mm in the rear and WRX in front with S/S lines all around.

Well, I'm about to pull my hair out. After doing the rears I jumped in and drove around the block. Pedal feel was great and the brakes were responsive.

I then did the fronts. Somehow I have a big air pocket in the system now as it takes three full strokes on the pedal to get it to firm up. This is sitting in the car with the motor off. By full strokes, I mean it pushes all the way down the floor pretty easy. After three strokes or so it firms up and quits moving further towards the floor.

I have an electric vacuum pump I've been using the bleed the brakes. At this point I went ahead and put in some Super Blue so I could tell when the fluid had flushed through. I've bleed all four brakes per the FSM order - RF, LR, LF, RR. I leave the pump running and pulling vacuum and will push on the pedal about 15 times before getting out and refilling the resovoir.

No change.

So I went ahead and decided to really flush the fronts. At this point I have cycled approximately 1 liter of fluid through the pass. and driver's side caliper.

No change.

I leave the pump running and pulling vacuum and will push on the pedal about 15 times before getting out and refilling the resovoir. At this point, my foot hurts.

One thing that didn't hit me until a few minutes ago, when putting the WRX calipers on I noticed that the bleed screw was at the 'bottom' of the caliper and not at the 'top'. But the little L and R on the caliper, or so I thought, indicated me to put install the calipers like that.

So, can someone with WRX fronts go out and verify that the bleed screw is on the low end of the caliper? By low end I mean the caliper is relatively verticle and my bleed screw is on the bottom half.

Could I have done something this stupid and installed the calipers on the wrong sticken' side so I have two big air pockets in the calipers that won't flush?

Any help on this would be greatly appreciated. I'm about to go nuts and my car's been down for two weeks trying to get this sorted out in my spare time. I've never had this much trouble swapping brakes.

I am also open to other suggestions.

[evolutionmovement]

Should be on top unless they did some weird shit with the calipers after 2002.

[ultrasonic]

True... bleeders should be on top. Think of it this way, the purpose of the bleeder is to remove air from the system. Just like the air in a sealed coke bottle is at the top, so is any air in your caliper. So the bleeder needs to be on top to allow the air to be purged from the system. Because that's where the air is.

Swap the calipers left to right so the bleed screw is on top, then bleed as normal, you should be in better shape.

Make sure it's right before you drive the car! If things don't come around you should get someone more qualified to look at it. Brakes are important...

Good luck.

[skid542]

Thanks for the verification guys. I don't know why it didn't occur to me until I was walking away from the garage this morning that this was the problem. I was 90% confident I had reversed things but wanted a verification.


I haven't driven the car with the fronts not working right. I am well aware of the importance of braking and making sure the system is right. I am the one who tracks the car and I am the one who hangs my life on the correct operation of the car - therefor I will be the one to make sure it is right. I haven't invested over $900 on my brakes just because they look cool... .


I guess if you work on anything long enough you're going to make a stupid mistake. I just hate getting caught . Doh'.

[jamal]

I could never get my vacuum pump to work well because air leaks through the threads of the bleed screw. If you're pumping the pedal with the bleed screw open, you still might be able to pull some air in with the pump going. Might want to give it a few pumps with a friend the old fashioned way to be sure.

[kimokalihi]

I had the same problem with my mityvac. It kept getting air in through the threads. I read that people have put tape over the threads to prevent this but I just gave up on that thing and did the old fashioned way.

One day I think I'll buy that really nice one that puts pressure on the top of the brake fluid resevior and keeps it filled while you just go from wheel to wheel cracking bleeder screws. That sounds sooo easy and can be done by yourself.

[skid542]

Thanks for the input guys.

I swapped the calipers and got everything working pretty well. My pump does pull in air through the threads but I found that it keeps enough suction on it that if I push the brake pedal down and slowly lift, it will draw all the fluid/volume it needs through the MC. Worked like a charm. I'm also only opening the bleed screw 1/4 - 3/8 of a turn to minimize the leakage.

The brakes feel great now and excellent balance. I went out and did some driving Sat. night and Sun. and will be posting up some final pictures and a review later on this week.

Thanks again.