New Rotors, New Pads = Mushy Pedal?? - PeachParts Mercedes-Benz Forum

JamesDean · #1 07-26-2012, 08:17 PM

Hey everyone,

This past weekend I put Akebono pads and R1 Concepts rotors on the 190E...excuse my surface rusty undercarriage...

I bedded the pads as per the instructions. 4x hard braking to near ABS trip 50-10mph..followed by 1x 65-15.. Park it for 20min..

They said it would take some 500 miles for the brakes to be fully bedded and all that jazz. Its bee around 400 or so maybe. My main complaint is that my brake pedal feels squishy/mushy. With my previous pads/rotors it was nice and firm. The only problem was the rotor warp and jitter...

I dont know why my pedal feels squichy/mushy now.. I didnt open any brake bleeders/ports.

Also my rear passenger brake is squealing like a pig. It just started doing this I think Tuesday/Wednesday. When I was putting the one pad in the shim/plate thing popped off and I had to re-secure it. I didnt put any anti-squeal paste. The pads did have a small bit of it in their box (I noticed AFTER I was done)...

Anyone have any ideas or what to do next?

Can't Know · #2 07-26-2012, 10:23 PM

When is the last time the fluid was flushed?

Hard pads can take a long while to embed enough to give you a good feel, but if it hasn't improved in 400 miles, that's not a good sign.

Where did you get the bedding-in instructions?

JamesDean · #3 07-26-2012, 10:33 PM

Quote:

Originally Posted by Can't Know

When is the last time the fluid was flushed?

Hard pads can take a long while to embed enough to give you a good feel, but if it hasn't improved in 400 miles, that's not a good sign.

Where did you get the bedding-in instructions?

Brake Fluid was last flushed on 8/17/10..its due for a 2 year interval on 8/17/12.

The 400 miles has been all turn-pike/highway so not a whole lot of braking involved.

The bedding-in instructions came with the rotors.

MBeige · #4 07-27-2012, 03:14 AM

When you pushed back the pistons to install the new pads, there may have some bubbles formed. How's the "bite"? Do the Akebonos bite strong?

I noticed with my Akebonos (w123) that I can't stomp on the pedal hard enough to generate brake lock when performed on an isolated road. The OE pads I replaced were ATE, but the rotors were warped so I put in new ATE rotors too.

You can always perform the brake bleeding to be on the safe side, and if the mushy feel does not go away, it can be attributable to either the rotors, pads or the combination.

Gilly · #5 07-27-2012, 05:11 AM

No fluid leaked out when you pushed back the pistons? Only suggestion I can have at thia point is bleed the brakes. After making sure all the clips are where they belong.
You should have used the paste, try that to cure the squeal.
Unless the spongey feeling and squeal are related, look over the squealer really good as an out of place spring clip will also give a spongey feel, and probably squeal a bit too.

Air&Road · #6 07-27-2012, 07:48 AM

Since the fluid flush is due anyway, go ahead and completely bleed and flush the brakes. It won't cost but about five bucks for a quart of fluid. Start by emptying the reservoir and filling it with fresh fluid, then use the whole quart and make sure you get all air out.

If the pedal feels mushy while the vehicle is stopped, it's not the pads. Even if it feels mushy when stopping, since the flush is due, just knock it out and then you know for sure the hydraulics are not the problem.

Hope this helps.

JamesDean · #7 07-27-2012, 08:04 AM

Quote:

Originally Posted by MBeige

When you pushed back the pistons to install the new pads, there may have some bubbles formed. How's the "bite"? Do the Akebonos bite strong?

I noticed with my Akebonos (w123) that I can't stomp on the pedal hard enough to generate brake lock when performed on an isolated road. The OE pads I replaced were ATE, but the rotors were warped so I put in new ATE rotors too.

You can always perform the brake bleeding to be on the safe side, and if the mushy feel does not go away, it can be attributable to either the rotors, pads or the combination.

When I did the brake bedding I couldn't get my ABS to kick-in. The bit seemed pretty good.

Quote:

Originally Posted by Gilly

No fluid leaked out when you pushed back the pistons? Only suggestion I can have at thia point is bleed the brakes. After making sure all the clips are where they belong.
You should have used the paste, try that to cure the squeal.
Unless the spongey feeling and squeal are related, look over the squealer really good as an out of place spring clip will also give a spongey feel, and probably squeal a bit too.

Nope no fluid leaked out. My reservoir is still nice and full. The brakes seemed better today actually. Less pedal travel for full stoppage. I think they're getting better. I do a lot of freeway driving so the 400-500 mile requirement might not really apply as I don't use the brakes nearly as often as one would if that 4-500 miles was all city.

None of the other brakes are squealing just the rear passenger. When I put the inner pad in the shim plate came off..I think that might have something to do with it. So I think tonight when I get home, I'll pop off that wheel and use the paste on those pads. Does the paste go between piston->pad or between shim->pad? Or should I do both?

Quote:

Originally Posted by Air&Road

Since the fluid flush is due anyway, go ahead and completely bleed and flush the brakes. It won't cost but about five bucks for a quart of fluid. Start by emptying the reservoir and filling it with fresh fluid, then use the whole quart and make sure you get all air out.

If the pedal feels mushy while the vehicle is stopped, it's not the pads. Even if it feels mushy when stopping, since the flush is due, just knock it out and then you know for sure the hydraulics are not the problem.

Hope this helps.

I agree, I think I've got a fresh quart of ATE Type200 Blue or Gold (Can't remember) still in its air-tight bag. So I'll probably toss that into the bleeder and go at it. Its due just about anyway. Like I said previously the brakes felt much better today than yesterday. Yesterday there seemed to be a lot more travel than today. I think this post must have scared them.

Another thing:
When we were changing the rear brakes, we noticed that the passenger rear parking brake was dragging on the rotor something awful. The one parking brake pad was worn pretty good and the other had heat cracks all throughout it. I've not used the parking brake since I've purchased the car (2006) so I just removed the pads and put all the important bits in a plastic baggy. I thought that with new rotors and a non-dragging rear brake that my fuel economy would increase (logically, no?) but that doesn't seem to be the case...

S124300 · #8 07-27-2012, 11:40 AM

A mushy brake pedal would surely mean air in the system? or is the pedal just soft and light to press - as it should be, but rarely is?
I've only ever fitted standard spec pads and rotors (mostly aftermarket brands) and they have worked nicely right out of the box. The only thing I do is to clean the oil off the rotors before fitting them; White spirit, rubbed over with a cloth, then a rinse with de-greaser solution and a dry over with a clean rag. I know you're not supposed to, but it works and I haven't had a problem with it in 20 years.

Can't Know · #9 07-27-2012, 11:51 AM

Quote:

Originally Posted by S124300

A mushy brake pedal would surely mean air in the system? or is the pedal just soft and light to press - as it should be, but rarely is?
I've only ever fitted standard spec pads and rotors (mostly aftermarket brands) and they have worked nicely right out of the box. The only thing I do is to clean the oil off the rotors before fitting them; White spirit, rubbed over with a cloth, then a rinse with de-greaser solution and a dry over with a clean rag. I know you're not supposed to, but it works and I haven't had a problem with it in 20 years.

Actually, cleaning the rotors before installation is typically suggested. A good strong solution of dawn dishwashing liquid works well to clean off the film of oil often left to prevent corrosion, as well as being sure skin oils, etc. are washed off.

James, if you haven't been braking much in 400 miles, then you wouldn't expect to see many changes. For you that might be more like 1,000 or 1,500 miles.

That said, if you're due for a flush I'd do that anyway as Larry has suggested.

Good luck.

JamesDean · #10 07-27-2012, 11:55 AM

I dont think there is air in the system as I didnt open it...

JamesDean · #11 07-27-2012, 11:59 AM

Quote:

Originally Posted by Can't Know

Actually, cleaning the rotors before installation is typically suggested. A good strong solution of dawn dishwashing liquid works well to clean off the film of oil often left to prevent corrosion, as well as being sure skin oils, etc. are washed off.

James, if you haven't been braking much in 400 miles, then you wouldn't expect to see many changes. For you that might be more like 1,000 or 1,500 miles.

That said, if you're due for a flush I'd do that anyway as Larry has suggested.

Good luck.

I think you're right and that I wont see anything REALLY improve until I hit more miles as I'm not braking much.

d.delano · #12 07-27-2012, 12:42 PM

From the pics it seems as though the rear left has a SS braided hose and the right has a standard rubber hose. At least that's how it appears. Could this be an issue? From my understanding they're not supposed to be mixed.

JamesDean · #13 07-27-2012, 12:45 PM

Quote:

Originally Posted by d.delano

From the pics it seems as though the rear left has a SS braided hose and the right has a standard rubber hose. At least that's how it appears. Could this be an issue? From my understanding they're not supposed to be mixed.

A few years ago I thought my issue might have been brake hoses so I went about replacing all my SS lines with rubber but I couldnt get that rear right one off. I didnt want to round the nut so i threw in the towel and said I'd toss it to the shop...never did get around to that. I dont think them being mixed would cause too huge of an issue though. It didn't before the rotor/pad change

Can't Know · #14 07-27-2012, 12:53 PM

Quote:

Originally Posted by JamesDean

A few years ago I thought my issue might have been brake hoses so I went about replacing all my SS lines with rubber but I couldnt get that rear right one off. I didnt want to round the nut so i threw in the towel and said I'd toss it to the shop...never did get around to that. I dont think them being mixed would cause too huge of an issue though. It didn't before the rotor/pad change

Yes, I also think that's a red herring, but it's a good sign people are looking closely at the pictures.

James, I think Larry made a good point when he asked if the pedal was mushy when you're stopped. If it is good and hard when you are stopped, then there isn't any air in the system and since you noted you hadn't opened it, there's no way it could have gotten in anyway. There are some instances where pushing all of the old, degraded fluid backward through the lines causes problems, but hopefully that's not what you're facing (and those problems are not usually "mushy" anyway).

So if the pedal feels fine if you are stopped, but just seems to require extra time/pressure/travel from speed, and there is no pulling or grabbing, I would bet the brakes just haven't fully bedded-in. The process you described wasn't any I've seen (or used) before and with the harder Akebono pads it is going to take longer anyway.

I would go ahead and flush the fluid, and then I'd try a drive or two across town where you actually get to use the brakes with some regularity.

Good luck.

d.delano · #15 07-27-2012, 12:56 PM

Interesting as the SS hoses (by the little yellow band around the rear left I might assume it's a Goodridge G-Stop hose which is considered the best) are definitely not supposed to cause a spongy pedal. I just bought a set and the box states to not mix the two types.
Rubber hoses flex under pressure whereas the SS ones do not, leading to a firmer pedal feel.

Just yesterday I was going to replace the rear rotors & pads and install all new SS hoses. It was 98°F outside, bugs were having me for dinner, and I just couldn't get that first rotor off of the hub. It's on there and I do mean good. I tried to then undo the top fitting for the brake hoses by using a modified box end(the line wrench set I bought curiously lacked an 11mm) and it slipped on the hex. It slightly marred the nut but not enough to ruin it. I took all that as a sign I should put it back together and take it to a shop. I hate it when that happens. Bought a Motive bleeder and everything.

Another thing I've noticed about your setup is the rear rotor seem to be vented, and these cars have solid rotors stock. How does that work? Seems like the vented rotors would be too thick for the calipers.