Bleeding Brakes (spongey feeling)
 

I installed my new 400E 4pot front calipers on my 87 260E but the brakes are very spongy. I have to put it all the way to the floor for it to even "feel" like it is braking. I replaced rotors + pads + fluid + brake lines...but this is not a bedding in mistake. The brakes are beyond normal for new rotors and pads -- Far, far too spongy.

I figure it is air in the lines and I may need to bleed the brakes again.

I was using a motive power bleeder before...How do I know when to stop bleeding since the fluid is new in there and how can I make sure there is no air? (It was my 1st time bleeding so maybe I made a mistake?)

Any other ideas on why it could be spongy?

Thanks

When you use the power bleeder, after you pressurize the system, open the bleeder valve on the caliper and let brake fluid flow out into your catch bottle until you see clear and clean fluid that is free of air bubbles. You may want to use a different color fluid such as ATE super blue to be sure you're getting all the old fluid.

......Oh yeah......If you disconnect the power bleeder from the system wrong, I think you will force air into the lines. As the directions should state, if there is any fluid left in the bottom of the bleeder after bleeding, tilt the bottle to the side and unscrew the bottle cap, not the MC connection, to release pressure. Then you are safe to unscrew it from the MC. This is just my re-collection of the directions, its been a few years since I last used my Motive unit. Could be completely off base. :D

I'm sure you know to start at the farthest wheel away from the MC and work your way to the closest (gotta ask, since it's your first bleeding :D).

Ahhh maybe that is where I went wrong. I ran out of fluid so I opened the bottle and filled it back up?

I'll definitely get that ATE Blue so I can tell the difference.

*****. Well there's your problem! If you run out of fluid, you end up pumping air into the lines for sure. You have to fill it up with more than you need. Can't fill it in the middle or you gotta start over. :D:D:D.

I didn't unplug from the resevoir though...only at the bottle, but nonetheless maybe that was my mistake. Problem was I got distracted and forgot that I didn't shut the stem on one of the calipers and when I got back 1hour later it was bone empty in the container.

I'll make sure to put in 3 quarts this time and not to open it :)

Fingers crossed that is the only issue!!
I DID feel the ABS kick on on a hard stop on the front calipers, so I don't think they are bad...It's gotta just be a fluid issue....

Will bleed tomorrow and let you guys know if that did the trick.

That ATE Blue is probably a dealer/online item right? Doubt local stores would carry something like that?

Running out of fluid in the bleeder will not introduce air into the lines UNLESS you also let the reservoir get low on fluid.

I use a Motive bleeder for flushing brakes, but I've never used it for bleeding brakes after the system has been opened. In that case I use the two man system. Depending on the person at the pedal, you may even have to do it with the engine running. If you do run the engine, set the ebrake, block the wheels and have a brake pumper that you can trust. This is not the time to use an 8 year old.

What is the system at the pedal? I've heard it can ruin the MC if done incorrectly....How many pumps? How far down?

Nah, where you "went wrong" is in failing to match master cylinder with slave cylinders, i.e. the calipers.

400E calipers work best with 400E master cylinder--as designed.

We just installed new back calipers yesterday. I was pumping the brakes while my dad bled them. But the brake pedal feels lifeless and i have to push it down pretty far to get good braking. I guess we still have air in the line and have to rebleed them?

Not correct. The earlier models used the same master cylinder with the 4pot calipers. I looked into this already and the MC upgrade was not necessary.

Got it :D

There was about 5+ big air bubbles that came out the rear and a couple on the front. I must have done it wrong somehow...Can't learn without making mistakes as I have found out quite well this past year...

HUGE difference. Everything is back to the way I would suspect it to be. But hot dang this thing stops GREAT!

You learn from experience, and you get experience by making mistakes.