e350 2009 no brake pedal after bleeding?

[Hussnainh8]

Hello

Asking on here as I am now desperate for help... I am a mechanic and have never encountered this problem before so I am very puzzled on how to fix it.

I had a Mercedes E350 2009 3.0 V6 come in today where the customer said his brake pedal is soft... I found the culprit which was due to a rotten brake line on the rear passenger side so I took the car from him and began my repairs.. I have cut the old line, flared a new line and joined the existed and new lines together using brake union nuts and female connectors. There are no leaks now what so ever..

I then bled the brakes by the two man method (pumping brake pedal, holding it, opening the bleed nipple, then closing and releasing the pedal. Started at the rear passenger then rear driver, front passenger and lastly front driver. Doing this, I tried the brake pedal and it just goes to the floor!

Then I researched and people said that you need to cycle the SBC on using a STAR diagnostic which I dont have so I attempted it with a Launch X431 and a Snap on machine but they both dont have special function to turn the SBC on.

Failing that, I then attempted to use my pressure bleeder to bleed the brakes, done all 4 wheels starting furthest away from the MC and the pedal still goes to the floor!

I know im definately not doing anything wrong so whats going on and why are the brakes not bleeding?

I tried driving the car (empty road) and slamming the brakes on to get the SBC to kick in and nothing happened, no lights on dashboard... Car brakes if I press the pedal far in but seems its only using half the brakes?

I definately dont have any leaks and have bled the brakes numerous times now so whats going on?

Dropbox

www.dropbox.com

heres a video of the pedal... ignore what I say as I was sending the video to a fellow mechanic who also doesnt know what it could be.

Thank you for all help.

 

[Blobcat]

Hello and welcome

No SBC on a 2009 E-Class, they replaced it with the facelift W211 E-Class in late 2006

 

[AMGeed]

As above, a 2009 E class doesn't have SBC braking.

If the pedal goes to the floor I would suspect there is still air in the system despite it being bled numerous times.

Going back to the old method with a bleed tube in a bottle of brake fluid are there any air bubbles in the fluid when you open the valve?
I'd keep bleeding it until the pedal goes "hard"

 

[malcolm E53 AMG]

Probably air trapped in the master cylinder which may need bleeding off the car

 

[mattkh]

What did you do at the brake fluid reservoir end when you cut the old line..?

 

[EmilysDad]

What did you do at the brake fluid reservoir end when you cut the old line..?

I'm sure the OP removed the cap then screwed it back on again with a piece of polythene under the cap

 

[Hussnainh8]

As above, a 2009 E class doesn't have SBC braking.

If the pedal goes to the floor I would suspect there is still air in the system despite it being bled numerous times.

Going back to the old method with a bleed tube in a bottle of brake fluid are there any air bubbles in the fluid when you open the valve?
I'd keep bleeding it until the pedal goes "hard"

Problem is when trying to pump the brake, it doesn't get firmer at all, I can pump 10 times and then bleed the brakes and try the pedal again only for it to feel exactly the same as it was before bleeding.

I will try the bleed tube method in morning but when doing it with pressure bleeder and two man method there was no bubbles coming out of the bleed nipples just fluid.

Also worth mentioning, usually when you pump the pedal and open nipple, fluid should come out with a bit of pressure but on this car it comes out more of a steady stream (no air just fluid).

 

[Hussnainh8]

Probably air trapped in the master cylinder which may need bleeding off the car

Could this explain why the abs doesnt kick on when slamming brakes while driving?.. I can literally feel the wheels skidding on the road but no abs kicking in.

 

[Hussnainh8]

What did you do at the brake fluid reservoir end when you cut the old line..?

The cap for the reservoir was still on if thats what you mean, cut the old line, flared and put new line with the existing line that was good and then opened the cap, poured brake fluid, took around 1.5 litres and then tried bleeding while keeping eye on fluid... Pedal still goes to floor. No leaks as reservoir still full.

 

[EmilysDad]

... took around 1.5 litres and ....

That's a lot of fluid. I removed a caliper from Emily's car the other day to replace the seals in it. I only used a cup full if that, of brake fluid when I bled it afterwards.

 

[Hussnainh8]

That's a lot of fluid. I removed a caliper from Emily's car the other day to replace the seals in it. I only used a cup full if that, of brake fluid when I bled it afterwards.

That's because the brake line was corroded and losing fluid as it is and then when I cut the old line I left it for the next day to put new one on so the fluid must have been completely empty as the old fluid would have leaked through the cut line over night.... Even after pushing fluid through and bleeding of any air, I still dont get a hard pedal, granted when bleeding I couldnt see any air coming out so maybe there is a air lock somewhere but where?

 

[EmilysDad]

That's because the brake line was corroded and losing fluid as it is and then when I cut the old line I left it for the next day to put new one on so the fluid must have been completely empty as the old fluid would have leaked through the cut line over night.... Even after pushing fluid through and bleeding of any air, I still dont get a hard pedal, granted when bleeding I couldnt see any air coming out so maybe there is a air lock somewhere but where?

Though it's not something I've personal experience of but it sounds like you've emptied fluid from valves within the ABS block, for which the ABS needs cycling while the brakes are bled.

 

[Oldspanners]

As above or try bleeding at the master cylinder connections as it seems that it's not drawing in fluid to push around the system. It may also be that bleeding by pumping the pedal it has ruined the seals as there can be corrosion behind where the piston usually stops and going past this when the pedal goes to the floor has destroyed them.

 

[Mr Greedy]

Whilst it doesn't have SBC, I thought with the right tool (STAR) you could still activate the ABS pump whilst bleeding the brakes. This is something that should always be done when changing the brake fluid on my old Alfa 145

 

[Jason63]

If you left the pipe open overnight I think you have drained the system. You have air trapped somewhere, most likely the Abs pump.

What I'd do is use a pressure bleeder combined with diagnostics to run the service function to bleed the Abs pump. You'll then start to see the air coming out of the bleed nipple.

If I remember correctly you get the bulk of the air out of one of the front bleeds you then still need to bleed all 4 corners.

 

[Cole@MBS]

We come across this a lot, we use a power bleeder at 2 bar as well as someone slowly pumping the brake pedal! Works every time! We have a lot of cars recovered into us from other garages, this method works a treat!!

 

[Hussnainh8]

Hello again guys...so today another day wasted... I have tried bleeding with vacuum bleeder set at 2 bar, made no difference .. i then tried the two man method again, no difference... I then also tried the traditional hose in bottle filled with brake fluid method, made no difference.

I have also tried doing all this with the car running to see if it makes a difference but nothing. I have cracked open the line from the master, fluid no air... I have cracked open the lines from the abs pump, fluid no air. Although when cracking open the lines for the pump, not much fluid comes out... its like a steady stream then it stops.. Why could this be?

I have come to the conclusion that the brake servo/master needs to be replaced as someone mentioned earlier that if you press the brake pedal too hard the seals go out of place... Seeing as the customer had the car before me and must have been driving the car with a leaking line, maybe he pressed the pedal hard in then also me having the car and bleeding the brakes, pressing pedal in as well.... Thats all i can think....... Something worth mentioning..... My brake pedal pumping helper did say he could hear a "hiss" noise coming from the brake pedal? Except every time i tried i couldnt hear it....

If its the servo/master whats the method to test these as im now planning to remove the servo/master out of the car.

Thanks.

 

[Hussnainh8]

Hello guys

So I have put a new master cylinder on it now including the brake booster and now I get pressure at the pedal.. it gets hard if you pump the brake and stays hard when engine is off. However with the engine on its soft pedal and if i pump it, the pedal gets harder however if i hold the pedal in, it just drops down slowly. I have bled all lines and checked multiple times for leaks and cant find any leaks or air bubbles in the lines.. 1 thing to note is that I took off the lines from the side of the abs pump, 1 of them had brake fluid coming out but the other one was dry with no fluid coming out. I also removed the lines on the top of the abs pump and the 2 closest to the windscreen had fluid coming out but the 2 lines closest to the bumper had nothing coming out. Seems like fluid is not going to the rear calipers and for some reason it seems fluid is not coming from the master to the abs line?

I am running out of ideas what to do next on this car. I have bled several times and cant see any bubbles.

Thanks.

 

[Mr Greedy]

Have you been able to bleed the brakes whilst activating the ABS system via STAR?

 

[Hussnainh8]

Have you been able to bleed the brakes whilst activating the ABS system via STAR?

I haven't as I dont have STAR... I tried the old method by driving the car on the ramp and letting the traction control kick in while braking few times... I can see the traction control flash on dashboard so assuming the abs is working however even after that 2 of the lines going from the abs to the rear calipers havent got any brake fluid in them... 1 of the side lines (the bigger lines) coming from the master cylinder has fluid and 1 of them doesnt (not sure it its normal but im guessing there should be fluid in them both).

Trying to find someone with STAR as I tried activating ABS with Launch and Snap on but they both dont seem to have that function for this car which I found really strange as atleast one of them should.