drew32

Okay, this is a problem i've been trying to figure out for quite some time now.

First off, I have searched and believe I am nearing a solution. I just wanted to created my own post to get everything organized.

A while back I did a complete brake change... Lines, Pads, and Rotors. During the change I accidently let all the fluid run out of the lines while bleeding the back driver's side. Once i got everything back together and bled it, I didnt have brake pressure unless I pumped the brakes. So I took everything off and re-bled them, again no pressure unless pumped. Seven brake bleeds later I have some pressure but not full unless I pump them.

To solve this, I'm guess i just need to keep bleeding them and get ALL the air out.

Second issue is the brake squeak. After the fourth or fifth brake bleed I started to notice a constant squeak comming from my brakes. It would only go away if i pressed the brakes fully.

After searching around the forums the only guess i have is that my caliper springs ( the little pieces of metal that keep the pads seperated) are bad. I'm about to call Ray and buy new ones but I wanted to see if anyone had another idea of what it could be.

Sorry for this being so long but I wanted to try and explain everything correctly from start to finish.

beemer_beems

have you tried bleeding them from the master cylinder?

BillM

iTrader: (4)

You may have to bleed the abs or at the master depending on how much fluid drained out.
Did you clean/grease the new brakes? Made sure to put the shims back in. did you put the wire springs back. Is it a scraping sound? Pull the offending wheel and rotate it maybe something is in wrong or backwards.

drew32

How would i bleed it from the master cylinder?

Also, ive vaccuum bled it twice now which has helped but not fully.

Mahjik

iTrader: (1)

Undo the lines at the MC which are near the cap. You can get a bleeder kit from a local auto store or you can just get some brake line and a bender. Basically, run the lines back into the reservoir so it just cycles right back in and down to the bottom of the reservoir. Next, pump the brake pedal slowly and evenly for a few minutes. This will bench bleed the MC. Then you'll need to bleed the brakes as normal and you should be fine.

drew32

Do you think this will fix the constant squeaking as well?

DaveW

Squeaking is the brake rotor / braking components vibrating at their natural frequency, like a tuning fork. This can be caused by different pad compounds causing stick-slip. It can occur under light contact (normal during periods of not braking) or heavy contact during braking. Did you use aftermarket pads?

Fixes are usually a change of brake pad type, or addition of "anti-squeal" shims between the pad and caliper piston. Usually, going back to stock pads is the most effective solution.

drew32

I used Hawk pads. But i dont think the pads should be squeaking as much as they are. It is super loud.

DaveW

Well, IMO, there's not much you can do other than change pads. The friction characteristics of the pad compound while cold and under light load are critical, and are probably the culprit. Fresh (or newly-machined) rotors could help (new rotors have a rougher, freshly-machined surface), but often this is only a short-term fix. After the rotors wear-in a bit, the brakes will often resume squeaking.

Dave

Mahjik

iTrader: (1)

Are they the HP+ pads? If so, they are known to squeal so just get used to it. IMO, Hawk makes the worst pads on the market.

If they are not the HP+ pads, then it would be something Dave mentioned.

drew32

The rotors are brand new, still have the squeaking. I do believe i used Hawk HP+ pads so if they are known for squeaking I will see about getting other pads. First ill try some anti-squeak on them.


As for the bench bleeding of my MC...

Should i use the two hoses on the right side of the MC?

I saw one on the bottom left so i just wanted to make sure.