Spring Clip Grinding Rotor?? - PeachParts Mercedes-Benz Forum

JamesDean · #1 07-30-2012, 05:45 PM

Hey everyone,

As I was leaving work today (just getting on 77) I start to hear faint squeal coming out of my rear passenger tire area... I figured it was the spring clip like my last squeal.. So when I got home I was greeted by this:

I don't recall that groove being there the rotor when I installed it... I'm not sure what to do about this either. Should I just remove the spring clip for now? The driver side is quiet and problem free....

Rotor is still way too warm to try to remove the clip and examine further...

slk230red · #2 07-30-2012, 06:35 PM

Does the other side have a similar groove?

JamesDean · #3 07-30-2012, 07:56 PM

It does..but its not "natural"...

Both front rotors are smooth on that surface.

The driver's side is smooth on the inner plate, the outer has a groove.

The passenger has a groove and has been clearly eaten away.

The spring clip is actually missing some of itself...

I removed it and re-installed it.. I verified that it was seated in its normal position and tried to push the pads backwards away from the center point but I don't think it'll do much.

d.delano · #4 07-30-2012, 08:36 PM

They sell new pins & clips. You don't have to use the same old ones. Those look pretty bad. You could at least take a little time to clean the barnacles off.

My take is the clip material is not meaty or sharp enough nor is it strong enough to machine those grooves into the tough steel rotor material.

Looks like you've got the space madness and are freaking out over your brakes. At this point bleeding them should be the #1 priority.

JamesDean · #5 07-30-2012, 08:49 PM

Quote:

Originally Posted by d.delano

They sell new pins & clips. You don't have to use the same old ones. Those look pretty bad. You could at least take a little time to clean the barnacles off.

My take is the clip material is not meaty or sharp enough nor is it strong enough to machine those grooves into the tough steel rotor material.

Looks like you've got the space madness and are freaking out over your brakes. At this point bleeding them should be the #1 priority.

I'll tack a set on to my next order. I'll inevitable place one for the 300D's stuff...

I saw nothing else in the rotors path so I just assumed it was most likely the spring clip. My thought on the way home was the same as yours..that the rotor would easily destroy/chip away the spring clip..

And your right..the groove is visible in this pic here after I finished installing that rotor... However you can see that the inner half of the disc does have some wear..

JamesDean · #6 07-30-2012, 09:13 PM

It was just pointed out to me that I might have put the spring clip in backwards after today's examination... Anyone confirm this.. It looks backwards I think..

d.delano · #7 07-30-2012, 09:17 PM

Quote:

Originally Posted by JamesDean

It was just pointed out to me that I might have put the spring clip in backwards after today's examination... Anyone confirm this.. It looks backwards I think..

Definitely backwards. Think about the rivet. The rivet is not supposed to be stressed, and the way you had it was stressing it out.

JamesDean · #8 07-30-2012, 09:22 PM

Son of a cheeseball.. I just took a shower.. BRB

JamesDean · #9 07-31-2012, 06:38 PM

And the fun doesn't stop here folks...

On the way home from work today I hear some occasionally growling noises from the rear end.. At I got home I stopped at this one corner and I THOUGHT I heard an airplane flying over head..when I completed my stop I realized this was not the case..

You see when my friend and I put these rotors on a few weekend ago we discovered that the pass-rear parking brake was dragging hardcore. So I had my friend gut the parking brake. I've never used them in the 6 years I've owned this car so what the hell.

Well today I jacked up both sides of the rear end and put the tranny in drive. I rotated the rotor with a screw driver and some lug bolts.. I heard a noise but could not find it. I thought it was this metal backing plate behind the rotor so I removed the rotor only to find some twisted beat up metal...

I do believe this was causing quite a disturbance. Its my fault, I just assumed he'd completed it before he had to leave for work however I should have double checked before putting the rotor on.

After further inspecting the parking brake area, I put the rotor back. I put in three lug bolts and spun it with the screwdriver. Its spun pretty free. I mounted the caliper, and installed the pads and tried to rotate it again. Its was pretty difficult and make some noise as I did so. It rotated a bit, then got stuck, I applied more force and it moved past the spot.

I am now curious as to if my inner piston is sticking on this caliper.. I replaced the front calipers a few years ago but never did anything with the rears. When I obtained snow, tires some four years ago, I ground down a small area of the caliper so that it would clear the wheel adequately. This grinding down did not effect the operation of the caliper merely smoothed an edge. However I am curious as to if whomever I bought replacement calipers from would take these as a core... I don't know.

pmckechnie · #10 07-31-2012, 07:17 PM

It does look like the rotor has been very hot. When the rotors get red hot or close to it and then cool down, they turn blue. I would suspect the inner caliper was sticking. The earlier pictures show the outer surface to be bright silver color which looks good.
Paul

JamesDean · #11 07-31-2012, 10:20 PM

Paul,

Other than replacing/rebuilding the caliper is there any other remedy for a sticking caliper?

I just ordered a new set of stainless steel brake lines from WRXtra.com, $86 total.

I was thinking of just ordering rebuilt calipers as well but I'd rather spend the cash on my 300D..

pmckechnie · #12 08-01-2012, 07:28 AM

JamesDean, Years ago we would buy a rebuild kit and rebuild them. I don't know if kits are even available any more. If it was my car, I would replace both rear calipers. Usually if one fails, the other is close behind. If you are going to replace the brake hoses, that is the time to do the calipers. Only have to bleed them 1 time. Here is a trick I learned years ago to bleed the brakes with just 1 person and no power bleeder. It may work or it may not, but it is worth a try.
With the hoses and calipers installed, fill the reservoir with fluid. Sit a pan under each rear wheel. Open the bleeder on both calipers and wait. In a few minutes the bleeders will start dripping . Keep the reservoir full. When one starts dripping, watch it for a little while until you see no air coming out. Close that bleeder and watch the other one and do the same with it. When both are closed, pump the brake a few times. If the peddle is hard, you are finished. Some systems won't work this way when they have antilock brakes, some will. If they don't start dripping within 15 minutes, then go to plan B.
Ok all of you non believers, let me have it. I know the proper way to do this is spend a couple hundred on a power bleeder (which you may never use again) but If this trick works on your car then put the money in something else.

Paul

JamesDean · #13 08-01-2012, 08:01 AM

Quote:

Originally Posted by pmckechnie

JamesDean, Years ago we would buy a rebuild kit and rebuild them. I don't know if kits are even available any more. If it was my car, I would replace both rear calipers. Usually if one fails, the other is close behind. If you are going to replace the brake hoses, that is the time to do the calipers. Only have to bleed them 1 time. Here is a trick I learned years ago to bleed the brakes with just 1 person and no power bleeder. It may work or it may not, but it is worth a try.
With the hoses and calipers installed, fill the reservoir with fluid. Sit a pan under each rear wheel. Open the bleeder on both calipers and wait. In a few minutes the bleeders will start dripping . Keep the reservoir full. When one starts dripping, watch it for a little while until you see no air coming out. Close that bleeder and watch the other one and do the same with it. When both are closed, pump the brake a few times. If the peddle is hard, you are finished. Some systems won't work this way when they have antilock brakes, some will. If they don't start dripping within 15 minutes, then go to plan B.
Ok all of you non believers, let me have it. I know the proper way to do this is spend a couple hundred on a power bleeder (which you may never use again) but If this trick works on your car then put the money in something else.

Paul

Paul,

This is tempting to do as the calipers are only $47 from store... The core charge is pretty high though. I'm just concerned they wont accept my calipers as a core because I ground down one of the faces...

After I heard back from the mechanic today about my 300D..I'll make more decisions..

Ferdman · #14 08-03-2012, 07:06 AM

James, the one spring clip is definitely installed upside down. Compare the spring clip orientation in the picture where you're holding it to the picture immediately above it. It also appears that both pins are not driven in completely. Normally the pointed end of each pin protrudes from the caliper approximately 1/4". Use a punch to seat the pins completely.

Recommend buying new/rebuilt calipers from your local MB dealer so you're using high quality parts.