S60 No Pedal after Changing pads & rotors

S60 Blues · Post by **S60 Blues** » 01 May 2010, 01:43

So this seems to be a fairly common complaint, A soft or spongy pedal after replacing pad and or rotor. Well I am stumped and really need some sound advice. I had no issues with the brakes or pedal prior to this incident. I have also changed pads on this vehicle a couple of times. It a 2001 with under 70,000 miles.

History- Last weekend I finally replaced my struts, mounts, strut bushings, control arms, ball joint and links. I also replaced the rotors and pads. I didn't open the bleeders when retracting the caliper pistons, and i didn't crack open the master cylinder cap. The fluid made it way out of the breather hole. After completing the brake job I got in to pump up the brakes, it took forever to get resistance and I never got a firm pedal.

I started to bleed solo, pumping into a bottle. A got a better feeling pedal but it still was low. As soon as I started the car the pedal was almost on the floor. I could pump up a bit of a pedal but it would soon dropped to the floor. Sure feels like a bad master cylinder.

Next day I bleed the system with a buddy pumping away while I stood guard at the bleeders. We did back to front, cross way, front to rear. We got a firm pedal only to loose it when the vehicle was started. Then I did a gravity bleed and a couple minutes into it I would get some pin bubbles followed by some serious bubbling. I was baffled, how was the air getting into a closed system. The same thing occurred on each wheel. I finally realized that after a couple of minutes the bleeders were sucking in air through the threads. I dribbled a little fluid around the bleeders and the air bubbles stopped.

Questions:
So, I ordered a new master but I am not convinced it is the culprit. I took the old one out today and it pumps fluid forcefully out of both ports. Is that really any indication its good or does it need to be pressure tested?

I have been reading post on brake problems for days. I checked several times and yes I installing the spring incorrectly. So I am thinking my next move is to pull all the calipers off and ensuring the pads are seated properly as well as reinstalling the old master and trying it again. Or do I just throw on the new master?

I made myself a pressure bleeder to assist in the bleeding process, I doubt my buddy is coming back to pump the pedal for two hours. What is the correct rotation in bleeding the S60 system?

Any special considerations with the ABS system? Somewhere someone posted that soft pedals were expected after a similar brake job. He said he simply brought the car up to speed then braked hard to activate the ABS system and the problem was solved. I did try to lock up the brakes after day 1 as suggested. With a pedal hitting the floor it was pretty much just a suicide mission that I quickly abandoned.

THAT MY STORY, FEEL LIKE HELPING??

THANKS!

jda2000 · Post by **jda2000** » 01 May 2010, 08:03

did you reinstall the springs correctly? Incorrect installation can give you a soft pedal.

S60 Blues · Post by **S60 Blues** » 01 May 2010, 08:33

Yes. I covered that in my post, but I will check them aging today.
Thanks

Post by **polskamafia mjl** » 01 May 2010, 08:59

The correct rotation for bleeding is to start at the caliper that is furthest from the master and work your way closer and closer to the master. When you compressed the pistons, you left the fluid reservoir cap on, right? I wonder if you might have forced it to leak when you were compressing the pistons...

S60 Blues · Post by **S60 Blues** » 01 May 2010, 09:32

Thanks, that is the way I have always done all my brake work. Unfortunately last night a tec posted that the VATIS order for a S40 is FR, FL, RL, RF. I may have the wrong model listed but it was front then rear. Just wondering if it mattered on the S60? Do you know if the ABS requires any special bleeding care?

Yes I did force it to leek! I assumed the fluid came out the breather hole. Once I wiped it up there were no leeks in the following several bleeding sessions.

Post by **JDS60R** » 01 May 2010, 09:58

With a pressure bleeder you will not need a friend. You will need at least 15psi to help push the bubble through. Keep it under 22 psi.

Once you have assured the brakes are assembled correctly you should pull and clean the bleeders. You mentioned that air is getting past them. This is normal whne they are open. If it happened when it was closed you would have another issue. The quickest way to check for leaks is to pressurize with a pressure bleeder and look for leaks.

You just have air in the system. BMW uses a reverse bleed for this circumstance. You can get a large syringe at your local tractor supply or equivalent and attach a hose from the syringe filled with brake fluid to each brake bleeder. You then force
the fluid in and it pushes the air up ( as air loves to go while in a fluid) into the Master cylinder.
The only issue with this process is if the sytem is not clean then you may be forcing the contamination in the caliper up into the ABS or MC.

Usually a pressure bleed from 15-22 psi does the trick. Try that first and let us know. I just did a S60 where the line was completely empty ( homemade pressure bleeder ran dry and if forced air through the entire line). Customer was too nervous to try anything further. I pressure bled it and it came up perfect. You can use a home made pressure bleeder just keep enough fluid in it.

S60 Blues · Post by **S60 Blues** » 01 May 2010, 10:39

Thanks, it sounds encouraging. I am anxious to go try this bleeder and I appreciate your information.

I just looked my bootleg VATIS information. It states to use .2-.3 Mpa for ABS which is 29LBS-43lbs.
The vatis bleeding sequence and it states front then rear on the S60.

S60 Blues · Post by **S60 Blues** » 01 May 2010, 19:47

What fun. Wasted another day on the brakes with no results. I pulled and inspected each caliper and pads, everything is solid.
Bench bled my old master and used the pressure bleeder. I got a reasonable amount of air from the fronts but nothing from the back. Had the best feeling pedal in a week only to have it hit the floor when I started the engine. Repeated the process with a new master cylinder, same results. I easily pushed two large bottles of brake fluid through the system.

So my bleeder works but there is no way to achieve 29-43Lbs with it. In fact I would be worried about blowing the reservoir off the master. Now that I think about it I must of entered 2-3 Mpa in the conversion calculator instead of .2-.3

Why no air out of either rear. Even after opening the system twice for the masters??

I have to think it something in the ABS.

Post by **JDS60R** » 01 May 2010, 19:52

Have a friend step on the brake pedal and see if the brake booster is broken in half. ( The MC shouldn't move at all. )

If not
Do the reverse bleed now -with the syringe. Do it from all 4 corners.

Its fine to use higher pressure in the pressure bleeder if that is the spec.

S60 Blues · Post by **S60 Blues** » 01 May 2010, 20:32

Sorry I am not sure I understand your response.

Do you mean the booster could be split?

I am also not familiar with the Syringe reverse bleed, can you explain.

Thanks