[Soravia]

So I got 335i reman calipers and new pads and rotors on front and back, ECS Tuning steel braided lines, replacement hard lines on rear sub frame, and patched hard line from body to the rear sub frame hard lines (deleted mid lines temporarily).

I bled the brakes using pressure brake feeder on the reservior (10 PSI) and bleeder can on the bleed nipples. I also used ABS Pump Activation to get bubbles out of ABS pump.

I bled from the rear passenger to rear driver to front. I held down brake pedal using 35lb weight.

I still have spongy brake until I pump the brakes 3-4 times. What might be the issue?

[feuer]

Originally Posted by Soravia

I held down brake pedal using 35lb weight.

Is that part of the procedure?

[avocet]

Get a vacuum pump or get a second human to pump and hold the pedal while you bleed. Report results.

[Soravia]

Originally Posted by feuer

Is that part of the procedure?

I don't have second person

[TheMidnightNarwhal]

Originally Posted by Soravia

I don't have second person

You don't need a second person. I did mine alone with pressure bleeder.

IIRC to do the bleeder procedure you first flush all 4 brakes as you would normally.

Then for ABS, keep pressure bleeder connected, you open bleeder, go in driver seat, start procedure on ISTA, pump pedal 5 times, then go out and close valve.

[mweisdorfer]

Originally Posted by Soravia

So I got 335i reman calipers and new pads and rotors on front and back, ECS Tuning steel braided lines, replacement hard lines on rear sub frame, and patched hard line from body to the rear sub frame hard lines (deleted mid lines temporarily).

I bled the brakes using pressure brake feeder on the reservior (10 PSI) and bleeder can on the bleed nipples. I also used ABS Pump Activation to get bubbles out of ABS pump.

I bled from the rear passenger to rear driver to front. I held down brake pedal using 35lb weight.

I still have spongy brake until I pump the brakes 3-4 times. What might be the issue?

Old school bleed first. Bentley Repair Manual specifically states to have a partner.

1) place closed wrench over bleed screw (9 or 11mm)

2) place rubber, nipple on the bleed screw, which attaches to the tube going to the brake bleed can.

3) simultaneous tell your partner open as you open the bleed screw; your partner should start to pump the brakes all the way to the floor.

4) pump 10x; on a be 10th pump your partner puts the brake pedal all the way to the floor and says hold. Simultaneously, you close the bleed screw.

5) add more brake fluid to the Master Cylinder & close it up.

6) repeat 3x per wheel

7) start with passenger rear, driver rear, passenger front, driver front (in that order)

If that doesn't get the air bubbles out, then you have air in the anti-lock brake system. You have to use ISTA D to active the system, in order to purge the air bubbles out.

Make sure your bleed screws are functioning properly. If not, replace them. In the rust belt or a state that uses salt on the roads in the winter, it's common for the bleed screws to become corroded and not work right.

[techwhiz]

An easier way than the ISTA to activate the system is to gently tap the the ABS distribution module with the handle of a ballot to dislodge air bubbles. You might also want to hit the calipers with a rubber mallet to dislodge any bubble trapped on the the piston.

I did the above when I did my F30 retrofit and never had the bad pedal feel. YMMV

[Soravia]

The calipers are rebuilt, fronts are Duralast rebuild so they are quality stuff. They do grab and I haven't had any leaks after much work to clean up the old front hard line fittings, and the rear patched connections. I spot no drops or liquid on the paper towels I wrap around the fittings.

I activated the ABS module using the handheld device made for BMWs. I don't know about the caliper pistons. I have new pads in them so they are pretty tight around the rotors and pushed in quite a bit. Still working on adjusting suspension so I can try the bleeding again. I've gone through quite a few of Dot 4 bottles already.

[feuer]

Originally Posted by Soravia

I don't have second person

That is problem then. You need second person. Preferably someone who knows how to bleed brakes.

Originally Posted by TheMidnightNarwhal

You don't need a second person. I did mine alone with pressure bleeder.

Exactly! This is why I question his procedure. I hope he didn’t damage any parts in the process.

[TheMidnightNarwhal]

Originally Posted by Soravia

The calipers are rebuilt, fronts are Duralast rebuild so they are quality stuff. They do grab and I haven't had any leaks after much work to clean up the old front hard line fittings, and the rear patched connections. I spot no drops or liquid on the paper towels I wrap around the fittings.

I activated the ABS module using the handheld device made for BMWs. I don't know about the caliper pistons. I have new pads in them so they are pretty tight around the rotors and pushed in quite a bit. Still working on adjusting suspension so I can try the bleeding again. I've gone through quite a few of Dot 4 bottles already.

You still haven't explained the "need a second person" part and about holding your pedal down. Why do you say that?

[juld0zer]

when pressure bleeding, you do not hold the pedal down. Pedal must be in the fully up position to allow fluid to enter the master cylinder

[Soravia]

I started the pressure bleed without holding down the pedal. Then I used the weight to hold down the pedal to see if air was trapped in master cylinder. None of it made any difference. Still takes a few pumps to get the brake to stiffen up.
It grabs for sure on the first pump, but weak. Just enough to stop a slow roll. Definitely not leaking. I looked all over and concrete is dry, lines are not moist.

[juld0zer]

Do you hear the pump activate using your scanner?

I've never had any issues using INPA or ISTA/D for this scenario. I've done DSC valve blocks, master cylinders, calipers, hoses all without issue. Every car has had perfect brakes and safe to drive straight away.

10psi may not be enough. You can use up to 30psi but if you are worried about your equipment then don't go above 20psi. 20 is plenty.

[Soravia]

Originally Posted by juld0zer

Do you hear the pump activate using your scanner?

I've never had any issues using INPA or ISTA/D for this scenario. I've done DSC valve blocks, master cylinders, calipers, hoses all without issue. Every car has had perfect brakes and safe to drive straight away.

10psi may not be enough. You can use up to 30psi but if you are worried about your equipment then don't go above 20psi. 20 is plenty.

Yes, I hear ABS pump motors working. Bentley manual says 9 PSI, probably to cover for old plastic tanks.

The fluid flows well, not too fast like foot pumping but it comes out steady and I can see bubble if there was any to come out. But so far since flushing after the lines were drained for replacement parts, I haven't seen bubble, small or large.

I'll try again but I'm running low on Dot 4 in the pressure pump going to the reservoir.

[IllSic_Design]

Have you tried tapping the calipers and also ABS/DSC unit with a rubber mallet to try to release any trapped bubbles? This has helped others that couldn't get all the air out.

[Soravia]

Originally Posted by IllSic_Design

Have you tried tapping the calipers and also ABS/DSC unit with a rubber mallet to try to release any trapped bubbles? This has helped others that couldn't get all the air out.

I'll try that during next bleed. Use big rubber mullet or smaller poly end brass hammer?

[IllSic_Design]

I'd use a rubber mallet.

[juld0zer]

I'd be more inclined to use the wooden handle end of a rubber mallet than the normal rubber striking end because it is more precise and jarring in terms of bubble shifting ability.

Although I still believe INPA or ISTA assisted bleeding should guarantee a firm pedal.

Is there enough fluid in your pressure bleeder so that you don't pump air into the system? Did it fall over during the process? I usually fill a minimum of a litre and check/top up once I have bled two calipers.

It should be physically impossible but are the calipers installed on the correct side of the car? The hose is usually short enough that installing the wrong caliper should be impossible

[techwhiz]

Originally Posted by juld0zer

I'd be more inclined to use the wooden handle end of a rubber mallet than the normal rubber striking end because it is more precise and jarring in terms of bubble shifting ability.

Although I still believe INPA or ISTA assisted bleeding should guarantee a firm pedal.

Is there enough fluid in your pressure bleeder so that you don't pump air into the system? Did it fall over during the process? I usually fill a minimum of a litre and check/top up once I have bled two calipers.

It should be physically impossible but are the calipers installed on the correct side of the car? The hose is usually short enough that installing the wrong caliper should be impossible

For the distribution block, it's definitely the wooden end of the mallet.
Ever so gently. Just tapping to dislodge any bubbles.

[Soravia]

Car now at shop to replace the hard lines I had to patch due to rusted fitting leaks. They will bleed for me after that .
Thanks for the inputs. I didn't have time to bleed. Had to spend time on spring height adjustment before sending to shop for brake and alignment

[MightyMouseTech]

You sure you just don't have brake pads with tapered wear, or a loose wheel bearing? Both will give the symptoms you describe.

[Soravia]

Originally Posted by MightyMouseTech

You sure you just don't have brake pads with tapered wear, or a loose wheel bearing? Both will give the symptoms you describe.

New bearings up front, rears are tight. All new Duralast pads, rotors, rebuilt calipers.