W124 Front brakes still squealing - PeachParts Mercedes-Benz Forum

omegabenz · #1 06-05-2002, 02:34 AM

After all my past troubles, if you care to look at the previous posts. I bought brand new OE Mercedes front discs, textar pads with the coating on the back, etc. I put them on tonight. I cleaned the caliper, the hub, and the pad carrier.

I put a light coating of anti sieze on the hub so I can get the roto off at a future time. I put antisieze on all the edges of the backing of the pad, and on the back of the pad. I put antisieze on the pad carrier also.

The left front is fine, however the right front still squeals. I pulled the wheel off again tonight, and I put more coating on the pad and the carrier of the pads. I noticed that when I turned the rotor, spun it by hand, it seems like it wobbles. I wouldnt think that they would warp, I have had them on for twenty miles. I did the break in procedure described before.

Could it be possible that the hub bearing has some play in it? How much is tollerable? Could it be that my antisieze coating on the hub center off centered the disc? What do you guys think? I have been screwing with these brakes forever. I think that the wobble is causing the caliper to move back and forth moving the pads and then they bind any squeal any ideas.

The car is a 1987 300D turbo.

Thanks,

Austin

-fad · #2 06-05-2002, 12:55 PM

anti-seize overdose!

not even aware that anti-seize is part of the fact recc procedure

-fad

mushedroom · #3 06-05-2002, 12:59 PM

did you prime the pads?
shave em down a bit on the edges so it's more of a rounder edge instead of just a flat hard angle...
this helped on one of my cars....but you need a grinder to do that

omegabenz · #4 06-05-2002, 02:33 PM

One of my friends always uses antisieze as I described, and it was recomended in one of the posts.

I didnt grind down the edges because they are new pads and new rotors.

I think that the rotor is bent already or the hub has play in it. That's what I really think. Im going to mount it up on the lathe and check it out.

Thanks for your posts,

Austin

omegabenz · #5 06-07-2002, 12:27 AM

The front wheel bearings on both sides needed to be tightened. So I bought a new mastercylinder, front pads, rotors and senors, sandpaper brake pads to figure out that I need to just tighten the hub. Well, now the brakes stop on a dime.

Thank you everyone for your help,

Austin

omegabenz · #6 06-24-2002, 02:38 AM

Actually,

I just put in new wheel bearings tonight. I built a stand just like what mercedes describes in the manuals. I checked the hubs for play after my installation of new bearings, there wasnt even .001 inches of play. My mitutoyo indicator didnt even move (mitutoyo is one of the best brands).

THE brakes still squeak.

The car handles better with the new bearings.

So far, I have new master cylinder, new front pads, new rotors, new bearings, etc.

Any more recommendations.

Austin

csnow · #7 06-24-2002, 11:53 AM

How frustrating!
You've put so much into this.

Does it squeel when you are not braking as well?

Does applying the brakes make it go away?

mushedroom · #8 06-24-2002, 12:01 PM

ear plugs?
set of 8 for 2.99

mine squeal too and i find that really really really loud music and a good set of ear plugs tend to work quite cheaply and nicely!!!!

woo hoo!!!!

omegabenz · #9 06-24-2002, 01:01 PM

They were squealing when you make turns, thats why I replaced the bearings. There was like .01" of play in the hub which is about .12 mm, but now there is not even .001" of play which is around .01mm. My dial indicator didnt even move. They do not squeak when driving.

They only squeak sometimes when applying the brakes. The car handles better with the new bearings.

See my little brother is turning sixteen on wednesday, and I am trying to have all the problems ironed out for him, but I have been doing these brakes for over two months. He said I dont want them to squeak. I have done everything. I told him, just drive it around and see if it does it. Now the ABS does NOT kick in anymore even if its squeaking. I cleaned off the abs pick up on the hub so that may be helping too.

Ear plugs. He'll probably just put in a stereo. He has a stereo in the rangerover, but he decided he wanted the benz instead so it'll probably go into the benz.

Thanks for your replies.

Austin

haasman · #10 06-24-2002, 01:11 PM

Austin

I hear you about them thar squeaking brakes!

I had a 300SD which did the same thing. Drove me crazy! a couple of thoughts:

Have the flexible brake lines between the metal lines and calipers been replaced recently? I noticed the mileage. I was told to do this on the SD and it eliminated the noise. I guess the idea was that the lines were flexing and not allowing full pressure. I was at first skeptical but afterwards very pleased.

Also I used on a different car a product called CRC - Disc Brake Quiet found at NAPA stores. The product is orange and is a silicone based paste. It attaches the pad to the brake puck. The idea being to keep the pad from wiggling and vibrating.

Hope this ideas help.

omegabenz · #11 06-24-2002, 01:16 PM

The petal feels good. The lines have probably never been changed. The car is 87 300D that has 130k miles on it.

Wonder if one of the lines has blockage and its putting on uneven pressure.

It's just upsetting me because my brother doesnt want squeaking. I could care less, my car does it, but I dont care.

Austin

csnow · #12 06-24-2002, 03:04 PM

Just as a data point:
I always use a silicone-based paste like haasman described.
Never a squeal problem since.
I have never tried the grease method MB specifies.
I'm not sure that is a factor here or not, though I started using the silicone stuff 15 years ago when I had squeal problems on a 450SE.

Another possible remedy would be to try a different brand of pads. Squeal potential certainly varies depending upon the pad compound.

haasman · #13 06-24-2002, 06:22 PM

csnow

Are you referring to the silicone lube paste or to the silicone that dries and sticks the pad to the puck?

csnow · #14 06-25-2002, 09:22 AM

I mean the sticky adhesive stuff. Usually bright orange or blue.
I was very surprised to see the MB manual specifying a grease on the W124 pad backings, but I have always had good luck with the sticky stuff, so I have stuck with it (so to speak...).

If you can get the grease off, you may just want to give the adhesive stuff a try.

[Tip: The newer stuff with low VOCs is ruined if it freezes.]

Just for reference, I put on ATE pads about 1 month ago with new ATE rotors. No squeaks. I usually choose carbon fibre 'sport' pads, but I was not able to get them at the right time. These OEM type pads are working well enough, so I may just stick with them.

I did have occasional squealing before the brake job, but I did not own the car when the previous pads were installed. I also took in some slight excess play in one of the hubs when I repacked them.

If there is enough play, the ABS sensors can rub on the hub and damage the sensor. That may explain why you had problems here from before your bearings were replaced. They can also get dirty enough to foul (been there), since they are magnetic, and they collect rust particles.

omegabenz · #15 06-28-2002, 04:11 AM

Since we are in america, it was once said that here, we would rather have brakes not stop, than squeak.

I think that if you dont want your brakes to squeak, you just have to stop harder and faster.

I cant figure it out....lol. I am going to deglaze them with the sand paper tool, then I am going to let my brother deal with it.

Austin