Anyone care to take a crack at this brake problem?
1998 E320 W210 Sedan, 99,000 miles. New calipers 2 yrs ago. New Front rotors last yr, New front pads 6 months ago, rear pads have 30% left. ASR

Took the car in for new tires and the mechanic told me the front anti-rattle springs were missing off the front calipers. I believe I wanted to put new ones on 6 months ago at pad change and forgot. The brake pedal is extremely firm, brakes work well, no noise.

Ordered two springs and installed them. Immediately the pedal goes to the floor on the first application. Took the car to the MB dealer and explained problem and they thought it has air in the line and needs flushed/bled. Dealer bled lines and flushed and pedal continues to go to the floor. Dealer figures car needs new master cylinder. Got car home, pulled both anti rattle springs off and pedal is extremely hard again and brakes work great.

Figuring with springs off the caliper pistons/pads are up against rotor. With springs on the pads and pistons are returning to slightly open position. Going to bleed brakes with pressure bleeder and make sure all air is out of lines. May also pinch off all caliper hoses and see if I have a firm pedal which would rule out master. Open each caliper hose and see if pedal goes to floor which would isolate a bad hose or caliper.

Any thoughts???

 

I hate brakes. They are the bane of my existance. No matter the brand, MB, Honda, Toyota, Jeep.... I have brake gremlins that love to cost me money. I'll be curious to learn what someone who has had a similar problem tells you about this. It sounds somewhat unsafe if you ask me. Maybe a "if it ain't broke don't fix it" type of thing..... Good luck.[8D]

 

Hi.

Be careful!! You should only work on brakes if you are competent.

Sounds as though the "anti rattle" springs are the wrong type or have been fitted incorrectly.

However, can't really think how you could fit them incorrectly. There are designed in a way so as to prevent incorrect fitment.

Suspect that the dealer has just taken advantage of the opportunity to earn a few dollars. Why should the brakes need bleeding (or the master cyl need replacing) if everything has been OK for several months and the ONLY change the intro of the (incorrect?) anti rattle spring? or retract shim.

How about contacting me thru PM and I will give you my email so that you could send a few pics of the pads, springs and calipers.

The anti rattle springs are designed to apply load to the pads in a direction at 90 deg to the line of force from the caliper pistons!!

Sometimes an anti squeal "shim" is fitted in between the caliper piston and the pad but this is only a few thou thick and although it does push the pad off the rotor it does so only by a few thou so as to stop the pads rubbing.
This few thou "retract" gives a longer pedal.
The rubber hydraulic caliper piston seals cannot always be relied on to provide adequate retract to preventr light contact (promotes squeal) from occurring.

Pedal goes to the floor?
Could you mean that the pedal travel is a little longer than without the shims fitted?
Yes you would feel some difference but its a matter of what is the "normal" feel.

AStuart

 

Thanks for the replies!
From what I can see there is only one way to install the springs. Two prongs in the two holes on the outside face of the caliper and the ends of the springs under the bracket ears. Have ordered another set. However the MB mechanic told me they were correct and properly installed.

Talked to the MB mechanic before he commenced work on the car. He informed me they use a pressure bleeder from the Master cylinder. Now I am beginning to believe the flush and bleed was not performed as well as it could have been. I saw the car up on the lift and the brake lights were going on and off. I assumed they were just checking the brakes after pressure bleeding but now believe they were bleeding by pedal application. Also, the fluid in the reservoir is filthy which indicates they did not completely flush the system. Suspect they just bled the front calipers.

Either have air in the lines or in the master.

The dealership on several occasions have tried to sell me parts unrelated to the problem. I am even wondering if the mechanics get a percentage of the parts sold.

 

Hi,

Something is not right here.

The original post was:
........Ordered two springs and installed them. Immediately the pedal goes to the floor on the first application. Took the car to the MB dealer and explained problem and they thought it has air in the line and needs flushed/bled.

Response:
IF the pads were pushed back the pedal would likely go to the floor on the first application.
Part of the pad change process is to ensure that the pads have been "pumped" back out to the rotors to ensure that when the customer, or anybody else comes to drive the car especially in the confines of the shop, don't find a long brake pedal and end up hitting something!

So why was it necessary to pump the pads out if the only change was the fitment of the pad anti rattle springs.

Can't think why these needed to be changed anyway.

Agree that I can't think of a way that anti rattle springs can be fitted incorrectly BUT there is always somebody out there that does the improbable.

The anti rattle springs DO NOT CAUSE THE PADS TO COME AWAY FROM THE ROTORS when fitted. Direction of force at 90 deg.

Yes ABS requires a pressure bleed if (lots of) air gets into the ABS modulator. However if the car had a "rock solid" pedal before the springs were fitted where has the air come from?

Brake fluid should be changed every two to three years since it is hygroscopic (absorbs water) which renders it more likely to boil under arduous conditions. (Spongey pedal)

Strikes me that the garage (dealer?) that had your car in don't understand the basics.

Stuart

 

I too am amazed at this issue. How can a simple spring cause such a big difference in the pedal. I can tell you that without the springs on the front caliper the front pads drag against the discs when I try to spin them by hand. With the springs on, the discs rotate much easier indicating that they must slightly cause the pads to pull away from the discs, or the pad wear is at an angle having worn without the springs and the installation of the springs changes the angle of the pads??

The original springs looked rusted to me and that is why I intended to change them.
The dealership turned the car back over to me with a hand written note on the dash saying
"no brakes". Will let y'all know how this progresses.

 

Stuart to answer a little better-

"The original post was:
........Ordered two springs and installed them. Immediately the pedal goes to the floor on the first application. Took the car to the MB dealer and explained problem and they thought it has air in the line and needs flushed/bled.

Response:
IF the pads were pushed back the pedal would likely go to the floor on the first application.
Part of the pad change process is to ensure that the pads have been "pumped" back out to the rotors to ensure that when the customer, or anybody else comes to drive the car especially in the confines of the shop, don't find a long brake pedal and end up hitting something! "

With the anti rattle springs installed the pedal goes to the floor the first pedal application everytime the brakes are applied (not a one time deal). Subsequent pedal applications yield a harder pedal. Was intending on changing the springs due to apparent rusting of the originals.
Have ordered another set because I took off the springs after getting the car back from the dealer and have misplaced them.

I agree this problem is so weird I don't believe the mechanic believed me. They should have duplicated what I told them. I wonder about this dealership. The lugnuts were on so hard I had to jump on the breaker bar to get them loose. You would think they would know to torque the lugnuts, or are hoping to see me again soon with a warped rotor issue???

 

Quote: "...or the pad wear is at an angle having worn without the springs and the installation of the springs changes the angle of the pads??"

Maybe. Maybe Not.

BUT on thinking about this a little more MAYBE the issue is caused by the rust zone (Inner rather than outer zone) on the rotor.
As the anti rattle springs push the pads in a little further MAYBE the pad is NOW contacting the rust zone which in turn causes the pads to retract the caliper pistons.

Do you understand what I'm TRYING to say?

Stuart

 

I understand what you are saying. Will get the micrometer out and take some comparative readings across the face when I commence work.

 

Dumb question....but have you tried attaching the spring on just one side at a time and then tried the brakes. Does either wheel create the problem or do both need to be attached? I don't have any particuler idea in mind, just trying to narrow your search.