Got a 2014 c63 507. just got my calipers powder coated, replaced the seals and gaskets in the cylinder heads for the brakes. Did a brake fluid bleed and flush same time since I let them bleed when I took them off

redid the brake fluid and followed normal procedure to refill by pumping adding releasing etc. But not the break doesn’t get any grip until about halfway down the push. It’s squishy and doesn’t grab at the top of the push like it was before. I used a pressure bleeder at Mercedes to bleed it as well. Still same issue.

In my years model can the abs cause an issue here? Could it be the master cylinder? Brake lines? Etc. Trying to figure it out help would be appreciated

It would be pure coincidence that it would be anything other than air in the lines assuming all was well before you took the calipers off.

Did you spread the calipers with the bleeder valves closed? It doesn't sound like you did. But, if so, I've heard doing so can blow out the ABS seals.

Spreading the calipers with the bleeders closed is fine if you have the MC reservoir cap off.

Vacuum bleeder would work better, is that what you meant? Sounds like air in the lines. The front calipers have TWO bleeders each, make sure you do both. Tap lightly on them with a rubber mallet while bleeding as they can be stubborn, and make sure you start at the rear right first (furthest from the MC).

I took off the brake calipers as you normally would. I let the lines bleed out into bags so I wouldn’t get garage dirty didn’t have a bottle at the time. Had to turn car on and off a few times while calipers were off to turn wheels so brake pedal was pushed while the liquid was draining out. Don’t know if that would have affected anything.

Car sat for a week. Filled brake fluid before doing a manual two person fill starting from furthest to closest one person pumps and holds and other person opens valves bleeds it then closes.

Would i I have damaged anything putting pressure on the brakes while the fluid was draining or empty?

Sorry, I meant pressure bleeder above of course duh. I use a Motive and it works great.

Did you let the reservoir go completely dry during all this? If so then you probably sucked air into the master cylinder. In that case I think the remedy is to remove it from the car and bench bleed it.

Could it be the abs at all?

Another thing too is can we do a bench bleed for the master cylinder on this car? I had a Mercedes tech tell me they couldn’t.

The ABS itself doesn’t require anything special during a normal fluid bleed/change. Unless...


I don’t see why you wouldn’t be able to, it’s the same as if you were replacing the MC. If you let the system go completely dry then I don’t know of any other option. You will probably have to also cycle the ABS using a STAR diagnostic tool (unnecessary if the system wasn’t bled dry), but I’m not 100% sure of that process.

If I bled it dry again took all the current fluid out and started fresh again and did a bleed wouldn’t that push the air out of lines and master cylinders?

Good luck

haha what’s that supposed to mean I’ll keep you guys updated

Maybe related maybe not. I removed calipers in a 07 cls550 to paint. I accidentally bled out a line or two. Now I’ve bled brakes maybe a million times and have a pressure bleeder. No matter what trick I used I could not get rid of a squishy pedal.

I took it to an Indy and he hooked up star and cycled the abs while bleeding and holy crap all this air came out. Pedal has been perfect for years.

I talked to a tech and he said that since my abs is hydraulic that the star machine wouldn’t work since the system when doing a pressure bleeder is made to bleed with the abs as well. I’m sure there’s still air stuck in my lines or my master cylinder so I’m taking it to Benz next week and letting them do a bleed again and seeing how that goes. If not maybe replace my master cylinder. I’ve been keeping an eye on the fluid level to make sure I don’t have a leak.

Had to cycle ABS on BMW’s once air got into the system.
A mate swears he never did this he just bled it as best he could then went out and did some emergency stops to activate ABS then bled again.

i did that on mine a dozen times and abs activated but no fix. In the end when Star was cycling abs during a bleed it all came out.

There obviously has be be air in the lines somewhere, as he should have a solid pedal if all air was removed.

Just one thing about the talk of bench bleeding master cylinder...
I replaced the master cylinder and booster a few years ago on my 1982 300 SDL.
As part of the procedure, I decided to bench bleed the master cylinder (came with new reservoir too).

What I thought I was doing, was to create a situation where little to no air will be introduced into the lines, when the MC will be installed into the hydraulic circuit.

Years before that, I had a problem with my Alfa Romeo. The Alfa did not like the US formulation of brake fluid and therefore the seals swole in the MC. So I replaced the MC, then spent a month bleeding air out of the system.

So, since then, last step when I changed the MC in some of my older Mercedes, I lightly pressed the pedal, while fastening the brake lines to the MC. This was my way of saying FU to the air coming into the system..

Only this time, for 2 weeks, I could not understand what was happening, as the brakes were acting weird, started normal, then couple hours later, the travel of the pedal diminished and pedal felt stiff.
Then I thought about my procedure and got rid of this step and had good brakes after doing some bleeding.
I thought I outsmarted the situation, there was experience to say that I did, only to find out that I didn't and still had to roll my sleeves and bleed things to old fashioned way.

As far as the rest, I thought there is a procedure of filling the rebuilt calipers with brake fluid, before bolting them to the hubs and connecting the brake lines.
However, be careful with creating vacuum in the calipers before bolting the lines into them...
And starting the engine with the lines not connected, may have cycled the ABS pump and gotten air into it.

This is making me not want to take my calipers off to get powder coated lol. Sounds like a pain. Done it on other cars no issues though.

Just don’t let the system run dry. Plug the lines and everything will be fine.

Going off old man memory (it may actually be in the WIS), but I believe you can positive pressure bleed with the car running while very slowly depressing the brake pedal.

What did you plug the lines with?

Brake line plugs

Only reason I had issues is we let the system run dry. I also found a leak in the line of the front left caliper it wasn’t tightened enough when we put the calipers back in I noticed brake fluid under the caliper when I was cleaning. So I’m assuming now that there’s an air leak the system isn’t sealed hence my squishy brake. I’m going to get it tightened this week. Rebleed it then it should be good.

Ill keep you guys posted. Other then that no one should have issues taking them off and on if done properly which I didn’t do. Some brake lines if upgrades come with plugs or a screw system you can tighten. I have the original ones and I wanted to do a flush anyways so I let them run dry. Didn’t know it would cause this problem