Bled new Wilwood brakes but still spongy pedal

[jimandemma]

Hi all, I have fitted new Wilwood 4 pot calipers, discs and braided lines to my 75 C3. I tried bleeding the system with a hand pump to no avail, just kept pumping through air bubbles. The master cylinder has not run dry and currently have passed around a liter and a half through the system. Tried again today using the pump the pedal and hold, crack the nipple and tighten. No air appears to be in the system now but the pedal is still spongy to the floor. Can't work it out, can someone offer some advice. I have done bleeding before on the car with no problems, this has me stumped.

Cheers, Jim

[bfit]

tell me about it Jim
I spent to days last week doing the same thing .
and could not get a peddle .
 Are you starting at the  further  calliper first and working back to the closest

Did you bench  bleed the master cylinder

try opening the farther bleeder  and just let it gravity free for a few  hours, that's how I had to do it last time to  clear all the air.
then work towards the master cylinder.

if all else fails get a  set of quick bleeders

 This time I what and bought a vacuum  bleeder, sorted it out in 20 minuets     

[jimandemma]

Yes, started at furthest rear, inside and outside top nipples and worked my way forward to the caliper closest to the master cylinder. Have not bled the master because it hasn't run dry. Vacuum bleeder is not helping and draws air, where pedal pumping appears better with solid fluid when cracking the nipple. I have done this 3 times today in succession with still no pedal.

[Shane Finn]

You haven't mentioned if you have new pads as well.

Either way, check that the pads are flat, true and properly seated. If they are even slightly cocked, the caliper will be able to distort the pad backing plate to conform to the disk but the extra pedal travel to do so will be long, soft and squishy.

This is a common racing problem I've had where the pads get tapered by use.

[jimandemma]

Yes, pads are new and appear properly seated and true to the disc

[77CVT]

If you have rubber lines, clamp all 4.  If the pedal is still soft = master cylinder. 

If it is hard, get a helper and release each corner one at a time.  The pedal should only move a small amount if it is ok.  Re-clamp and do the next corner - if a corner you release moves the pedal a lot then that is your culprit.

[bfit]

if you have a second person .
crack the fitting at the master cylinder and then get the helper to slowing depress the brake  see if any bubbles are present start with the rear brake line first  then the front.
Bfit

[jimandemma]

OK, tried gravity bleeding to no avail. Tried the helper depressing the pedal again and now got a whistle from underneath when cracking the nipple and brake warning light came on. Tried again, whistle gone but brake warning light on. Fluids are normal front and rear of master cylinder. Starting to give me the sh#ts. Pedal is spongy to an inch off the floor. Pumping does nothing to the height of the pedal, hold, crack the nipple, no bubbles, pedal to floor, tighten nipple. No change with all 4 corners. I'll try the master next, cracking the lines.

[bfit]

Remove the switch sender and reset the valve,
That can be the problem, I have not seen it but I have read  that others have had this as the problem

[jimandemma]

No worries, will try tomorrow.

[jimandemma]

Cracked the lines at the master cylinder and a few bubbles came out of the front line. Reset the proportioning valve cylinder and have no brake warning light now. Bled brakes again with some air coming out of the front calipers inner nipples. Did all this with the master cylinder line on and clamped. Rear boot sucks down but front doesn't. No difference in pedal!!! I give up!! Have to get someone out to fix this as I'm beyond my capabilities

[jimandemma]

Correction, master cylinder cap on and clamped.

[bfit]

Don’t give up if it worked before you changed calipers then it will work again.
May be some one has a pressure bleeder.

Members anyone  have one.
Bfit

Ps what Sudurb are you in

[jimandemma]

North Arm Cove, 45km north of Newcastle. I'll buy a pressure bleeder and try that Friday

[bfit]

I suspect you still have air in the front half , hence it’s not pulling the oil down in that chamber.
Do you have assess to gear to make a brake line.

[jimandemma]

I have access to gear to make a brake line. It's pulling the fluid down in the front cylinder but not the front boot on the cap as the rear.

[bfit]

 but not the front boot on the cap as the rear

not sure what you mean by the above
BFit

[jimandemma]

Inside the master cylinder cap there are 2 expandable rubber boots that stop fluid swishing around when the level is down. When using the pump the pedal method bleeding the rear calipers, the rear master cylinder cap boot will get sucked down with the level bled from that rear section of the master cylinder. When bleeding the fronts, the front master cylinder cap boot does not expand with the fluid drop in the front section. I have also been bleeding with the engine running, so going to try again with the engine off, no booster.

[77CVT]

Seriously, try and clamp all 4 lines.  If you pedal is hard then it's not the master cylinder.  Granted, I've only ever done this on cars with a booster but should produce the same result.

[bfit]

If you can make up a  line  with about enough tubing  that you can loop over the top and back into the reservoir below the fluid then you can see what’s  happening