Soft/Spongy Pedal after SS Line install.

[patroklai]

Hello, I recently did an install of ss lines. Prior to the install, I had bled the brakes at the caliper (since I installed speed bleeders), and had a very high/firm pedal as a result. Since the car was up on jack stands, I picked up a set of SS lines and installed those. They went in dry, but after I went to bleed the car here is what happened.

1) Very little air came out of the rear calipers. But I bled them until no air or bubbles came out. This includes inner and outer bleeder valves.

2) The inner valve of the front calipers made strange squishy noises and endless micro bubbles kept coming out. After going through several liters of fluid, I ran a clear hose from the passenger caliper to the MC until clear fluid came out. I repeated this for the driver side front but by then, it seems I may have gotten all the bubbles out the passenger side.

3) I did bleed using the Correct X pattern given the brake circuits on this car. I drive a BMW M3 and have experience with BBK, SS lines, replacing and bench bleeding MC and replacing brake boosters. In addition to pressure bleeding, vaccum bleeding and the two man method.

However, this was the first time bleeding this car.

Another point to add is that I did try to use my motive bleeder using a metal cap adapter I picked up via Amazon. Unfortunately that cap wasn't able to hold pressure and made a mess. I also saw an exorbitant amount of air bubbles being pushed into the MC where I've never seen before with the BMW. I'm not sure if this was part of the issue so I wanted to call that out.

Does anyone have any experience bleeding a caliper with an endless supply of air bubbles? Never seen anything like it. I purchased a device to help me with the ABS bleed in case that helps. I'll have it tomorrow so we'll see but looking for input in the meantime.

Thanks.

[SIM GhostrdrZ]

I’d say you got a lot of air in the system which I usually do the old style brake bleed to get the air bubbles all out. Also you’ll most likely need to do abs bleed. You might check all the bleeder valve to make sure those are airtight.

Not sure how your using your motive but I always fill M/C and pump psi to it with a dry motive tank. I’ve had some pos cars that just need extra tlc. Bleed, drive, bleed, drive, etc.
Just make sure all the connections are airtight and there’s not a loose connection on your new stainless lines.
It gets frustrating chasing the air out.
Good luck

[patroklai]

Thanks. I picked up one of those autel abs bleeders. Should be here tomorrow.

Also, if there is air in the master cylinder, does it require bench bleeding? It would seem as if it can be bleed in the car given the straight angle. On my BMW, it's mounted at an upward angle which has cost me several dozen hours if brake work to get that pedal to firm up.

Seems it would be simpler on this car.

[SIM GhostrdrZ]

It’s probably the incorrect answer but even when I replaced my V6 M/C with a V8 M/C, I did not bench bleed it. Sounds like you know what your doing, just take your time to double check everything and look for the Easter egg air leaks

[patroklai]

That's good to know, thanks. Hopefully things will improve after the abs bleed. Will keep this thread updated

[patroklai]

Update on this. Tried a vaccum bleeder but no success with my speed bleeders. Only worked with regular bleeders so returned.

Eventually I found the right cap for the master and was able to get a good seal. Ran my pressure bleeder between 20-25 psi and used an autel device to run the abs auto bleed. Ran the sequence twice, then did a mild manual bleed on each caliper. For the most part I had little to no bubbles. Once I was done, pedal is firm when off but still had play/is soft when on for the first part of the travel.

Keep in mind the entire car is still on jack stands and no tires. The question I have is this, following a bleed, is it possible that the pedal may firm up once the car is on the ground? Or is pressing the pedal with the car on while on Jack stands and no wheels good enough to determine pedal pressure? I wonder this since the pads/pistons have no real incentive to retract from the calipers until the rotors are moving but not 100% certain this is the case. I plan to drop the car tomorrow and take it for a test drive. I know that when pads/rotors are replaced and the pistons retracted, there is usually some initial pumping needed for the pedal to come back.

Thanks in advance.

[patroklai]

Another update- after driving the car down on the road, the pedal did firm up. However, there is still that little bit of extra play but the brakes do inspire more confidence, just not as firm as I recall they can be.

I did another round of bleeding with the power bleeding which made things slightly worse, but on putting miles on the car eventually got better.

I have a feeling the motive pressure bleeder is somehow introducing air. As in, makes the fluid 'fizzy.'

I'm going to try a few more things here over the next few weeks but won't rush it as the car is definitely driveable.

Some things I plan to try:

1) Another pressure bleed with abs actuation
2) Manual bleed with bottle dispenser at reservoir (with ignition on)
3) I will reapply sealant to the speed bleeders at the threads (the two inboard bleeders leak at the threads when cracked open).

Any time I bleed it seems I get air out of the system. I'm not sure where its coming from but this usually happens despite the previous bleed showing clear fluid out the valves.

There's definitely air in the system, just not sure where.

[bertie]

Originally Posted by patroklai

Update on this. Tried a vaccum bleeder but no success with my speed bleeders. Only worked with regular bleeders so returned.

Eventually I found the right cap for the master and was able to get a good seal. Ran my pressure bleeder between 20-25 psi and used an autel device to run the abs auto bleed. Ran the sequence twice, then did a mild manual bleed on each caliper. For the most part I had little to no bubbles. Once I was done, pedal is firm when off but still had play/is soft when on for the first part of the travel.

Keep in mind the entire car is still on jack stands and no tires. The question I have is this, following a bleed, is it possible that the pedal may firm up once the car is on the ground? Or is pressing the pedal with the car on while on Jack stands and no wheels good enough to determine pedal pressure? I wonder this since the pads/pistons have no real incentive to retract from the calipers until the rotors are moving but not 100% certain this is the case. I plan to drop the car tomorrow and take it for a test drive. I know that when pads/rotors are replaced and the pistons retracted, there is usually some initial pumping needed for the pedal to come back.

Thanks in advance.

My buddy is looking at this Camaro SS project with very soft pedal issue. The current owner mentioned his son installed the ss line and wasn't able to solve it. We'll just finish installing the bumpers and bilstein shocks on the Raptor tomorrow before we can take a closer look. We're gonna use a speed bleeder and will search for a good cap for the master.