Bled new Wilwood brakes but still spongy pedal

[jimandemma]

I've got a hard pedal with engine off, soft to floor when running. Thinking maybe a booster problem now or vacuum

[bfit]

That's interesting,
Have to think about that

[bfit]

I'm wondering if that noise you heard was the booster?

I think you need to block the master cylinder at the master cylinder, and see if you can get a peddle with and with out the engine running.
a couple of dummy lines  with the tube silver soldered closed.
T prove that section is working correctly.
Bfit

[jimandemma]

Noise seemed to come from underneath the car, maybe the proportional valve. What I can't understand is the system was perfect before the brake change. I'll try another bleed this time with engine off, then also check for vacuum leaks at the booster. It's looking like I'll require a professional to come out and diagnose.

[bfit]

1 when you have a good pedal, hold the brake hard down with your foot, and start the engine
the peddle should push back against your foot as the vacuum builds up. but not drop .
let us know

2 what brake hoses did you use? you said earlier they are braded but what kind and what size.

3 what was your pedal like before you changed the callipers ( what was the travel short or go nearly all the way to the floor)

4 something else to check
loosen the master cylinder  push it forward a little and see if there is a fluid leak back into the master cylinder.

[jimandemma]

Started car with foot on the pedal, straight to the floor.

3/8" external diameter braided lines all corners as supplied with the Wilwood brake package

Pedal was good before I started with short to half way travel

Will try moving the master cylinder Sunday to see if there is a fluid leak

I reckon another bleed with the engine off with no booster is in order. Will do that Sunday as well.

[jimandemma]

Brake line

[jimandemma]

Brake line rear

[jimandemma]

Disc and caliper rear before

[jimandemma]

Disc and caliper after

[bfit]

Good quality brake lines they won't expand to any noticeable extent.

[Shane Finn]

Another thought:

Go to a hydraulic shop and buy fittings/bleeders to close the end of the lines to the caliper. That will totally eliminate the caliper from the equation. You are then only dealing with the master cylinder and plumbing.

Bleed the lines as you would a caliper and see if there is any difference. If none, then the fault is entirely in the plumbing and nothing to do with the calipers. If the pedal is hard this way, then the fault is within the caliper. You can then by trial and error figure out which caliper is at fault.

[bfit]

The fitting on the caliper end of the brake hose is AN3  ( 3/8  24 JIC ) these are not a common hydraulic fitting ,

Aeroquip 900599-3S  is the plug if you need them.

[jimandemma]

Bled the system again, this time with the engine off. First, I bled the bottom nipples and was surprised that air and old brake fluid came out of the nipples, especially when I have put nearly 2 litres of new fluid through. I then bled the top nipples and then top and bottom again. Little difference in pedal feel. Guys, I'm just going to get somebody around with more knowledge to fix this, I've had enough of dicking around with this for 8 days.

[Vettech]

What was wrong with the old one - except for the fact that they are G.M.

Are they still serviceable?

Have they been s/s sleeved & overhauled. I can see the paint.

You most likely know where I'm going here.

[jimandemma]

Discs had a slight warp and was not sure if the calipers were rebuilt in the past with SS sleeves. Wanted to upgrade to drilled discs and lighter calipers as well as improve aesthetics. No, not going to put the old ones back on, gone too far for that.

[bfit]

I understand the frustration

[wabco40]

I haven't read the whole post but I am guessing your having problems bleeding the brakes.

The only way I could bleed my brakes with Wilwood and standard calipers was to use a pressure bleeder. I tried for weeks doing pump and hold, gravity and a vacuum pump with no luck.

Using the pressure bleeder it took about half an hour to get a rock hard pedal.

[jimandemma]

Yes, thinking the same mate. Pressure bleeders are damn expensive though for 1 job. Got a mechanic coming out this afternoon, so will see how we go.

[bfit]

Yes, thinking the same mate. Pressure bleeders are damn expensive though for 1 job. Got a mechanic coming out this afternoon, so will see how we go.

good luck
I hope he sorts it for you quickly .
For my part I would buy a pressure bleeder it always useful even if you never use it again. A pressure bleeder was my next purchase after the vacuum bleed I purchased.
the  vacuum unit I got worked a treat
Vacuum Brake Bleeding Kit T&E Tools QS-2119K