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C230K Sport Sedan
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Discussion Starter · #1 ·
On my kid's '98 SLK230, the parking brake was damaged by AAA using the wrong lugbolts. The dealer replaced drum brake springs that were damaged and since then it intermittently squeals when driving (not when applying the parking brake). When you apply the parking brake while it's squealling, the noise stops. The dealer had it 4 times to fix and the last thing replaced was the backing plate which reduced the frequency of occurence but when it happens it's there at full volume. I took the brake apart and cleaned it up and put it back together and it all works fine but still squeals.

What I did notice this past weekend is that the noise starts when I go in reverse and apply the parking brake. It makes sort of a clunk sound when I do this and shortly after (in forward) it starts squealing and I pop the parking brake handle and it clunks and stops squealing.

Any ideas on what to look for?
 

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SLK 320 BRABUS Modded
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Erm why are you using the parking brake whilst the car is moving ?:eek:
 

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SLK 320 BRABUS Modded
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No you miss my point the parking/handbrake should not be used untill the car has stoped, but you say if you use it going in rev, it clunks. or have i misunderstood?


Sometimes cutting a grove 90 angle to the pad will stop a squeky pad or shoe,( lets the gas out ) but the cluck soulds like somthing is moving
 

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Golf R32 / Prev R170 SLK
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The design of the parking brake is very poor. The shoes move all over the place and can just rub on anything they come near too.

I would drive it a while whilst squeeking and open assembly to look for a witness mark and go from there.

Bazzle
 

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1998 Silver SLK 230
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38 Posts
Buellwinkle - Is the squeal coming from the left rear tire? I have that same problem with my 98 Benz and the same issue would pop up out of nowhere. My solution is similar to yours I quickly lift up on the parking brake handle while the car is in motion (less than 40mph) until I hear the clunk noise you mention and then lower the parking brake. The issue only seems to rear its ugly head when I back up the car and then travel forward.

This may sound a little twisted but I am glad to know I am not the only one experiencing this issue. After this batch of parts for my Benz comes in I will be migrating to the back wheels of the car to hopefully resolve this issue.
 

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2008 ML350; 2001 SLK230 (traded in)
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section-9 said:
This may sound a little twisted but I am glad to know I am not the only one experiencing this issue. After this batch of parts for my Benz comes in I will be migrating to the back wheels of the car to hopefully resolve this issue.
I've got the same problem as you and Buell - squeal comes from driver's side rear. I tap the brake pedal or pull the emergency brake and that usually stops it. I have already disassembled and that didn't work.
 

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2002 SLK 32 AMG, bone stock. 1987 190E 2.3-16 valve (destroyed). 2005 E320 new toy.
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The problem is that the shoes have shifted and been glazed. Since you already know how to pull everything apart, do it one more time and rough up the friction surface with VERY course sandpaper. The finished surface should be clean and flat, but "soft" if that makes sense to you.
Roughing up the inside of the drum can help as well, rough it up with strokes that run 90 degrees to the plane of rotation.
The design of these brakes is not much different from any other drum brake, and the remidies are the same also....:)
 

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Discussion Starter · #9 ·
I did that, totally took it apart, sanded the shoe surfaces and the inside of the drum. Maybe buying new shoes, springs and rotor make help, start from scratch with all new parts, afterall, they have close to 100K miles on them. My theory is that the shoes have worn a groove into the rotor. When they shift, the edge of the pad rides in this groove causing it to squeal. Although I sanded the groove and edge of pad, it still may rub when it shifts.

At Duval, shoes are $27 and each rotor is $36. The springs and clips shouldn't add up to more than $10.
 

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Discussion Starter · #10 ·
Duval is undergoing some system upgrade so I ordered from Autohausaz.com. It's about $24 for the entire parking brake kit shown below and about $34/rotor so it came out to under $100 with free shipping. I haven't done drum brakes in ages. If I remember I'll take pics for the forum in case anyone else with the problem wants to give it a go.


 

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1998 Silver SLK 230
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I am from the disc brake era and have never worked on a drum brake. If you could take pictures and possibly do a write-up for us it would be much appreciated.

Thanks again Buell
 

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2002 SLK 32 AMG, bone stock. 1987 190E 2.3-16 valve (destroyed). 2005 E320 new toy.
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Buellwinkle said:
Duval is undergoing some system upgrade so I ordered from Autohausaz.com. It's about $24 for the entire parking brake kit shown below and about $34/rotor so it came out to under $100 with free shipping. I haven't done drum brakes in ages. If I remember I'll take pics for the forum in case anyone else with the problem wants to give it a go.


When you pull off the retainer springs, stick a flat blade screwdriver through the axel hub hole and into the center of the spring, then turn 90 degrees. The book says to use needle nose plyers, but that doesn't work very well at all.
I just did that job last weekend on the 16 Valve, and the work is identical. Look very closely at the big springs on the bottom, there are two hooks. One hook is bigger then the other, the big hook goes to the higher shoe (can't remember if that's front or back).
The adjustment wheel should be lubed with a high temp grease or in my case I used Never-Seez, and the assy. must have the shorter end (the spur wheel end) face the front of the car. It's not hard work, but the strong springs tend to make the work frustrating .... You'll see what I mean when you start...:D
 

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Discussion Starter · #14 ·
Finally figured out what was causing the squealing. I put new shoes and springs on but then I couldn't get the rotors on so I took it apart again and this time the brake shoe expander fell off. This is the lever at the bottom that pushes the brake shoes out when you pull on the brake handle. This part was tweaked and bent from the original incident with the spare and longer bolt and AAA. I bought a new one, $10 and while I was at the dealer I asked them to put it on and did it for free if I paid for the other side (with the new shoes and springs I bought) and they did it whilst I waited. Hasn't squealed since. Kid is happy again.

I don't recommend this as a do it yourself job, it's really a PITA to line everything up and put these high tension springs on. I did drum brakes before but this is a tiny annoying drum brake and you have to work through holes in the hub, not easy. The mechanic figured 90 minutes labor but it took him 3 hours, thank goodness I brought my laptop and have a wireless broadband card.

I do recommend that if you put longer lug bolts on in the rear and damage the parking brake that you spring for the $23 for a complete shoe/spring kit (autohausaz.com), backing plate (about $15) and new parking expander for $10 from the dealer and have an independant put it on. This was the 5th time at the dealer for the same issue. Finally I can put it behind me. Thanks to Bazzle and others that helped and contributed to the post and hope it helps someone else out.

Sorry for no pics, I lost the bent piece. If I find it I'll post a pic.
 

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2002 SLK 32 AMG, bone stock. 1987 190E 2.3-16 valve (destroyed). 2005 E320 new toy.
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Damn Buellwinkle, three hours for a trained mechanic? It didn't take me that long, and I changed out the actuator cables as well. The cables were rusted to the point that I had to cut them apart with a Dremel tool....:) This was on my 16 valve, but the installation is virtually identical.
Your right though, the springs are a pain to change out due to their strength and location. According to the manual, you replace the top spring first, then the bottom one. The two retainer springs are easily done with a screwdriver through the center. Push in and twist 90 degrees.
 
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