Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 01-11-2001, 11:56 AM
Registered User
 
Join Date: Nov 2000
Posts: 168
WARPED ROTORS

I have a 1980 300cd. When I bought the car it made a very noticeable pulsing noise that was most evident while making left right turns at highway speed. The speed of the pulse was determined by vehicle speed. When stopping the brake pedal would pulse also. I took it to Midas for a complete brake inspection. The inspection showed that the left front rotor was warped. So, I had both the front rotors turned and the wheel bearings repacked. The noise was gone, and the brake pedal was back to normal. It's been about 2-3 thousand miles since then and the noise is starting to come back along with the slight pulse in the brake pedal. The car still stops straight even upon hard braking. Is it the rotor getting warped again? Does anyone know what could have caused it? I would like to fix it one more time. But I would like to fix the cause for my rotor being warped. The rest of the initial inspection showed everything else to be fine. I would appreciate any and all advice on this matter. Thank You, andy

Reply With Quote
  #2  
Old 01-11-2001, 12:06 PM
engatwork's Avatar
Registered User
 
Join Date: May 2000
Location: Soperton, Ga. USA
Posts: 13,648
andy, do you drive it hard with a lot of use of the brakes then wash it? I have heard that if the brakerotors are real hot and you spray cold water on them (like in a car wash when you wash the wheels) then there is a possiblity that they can warp. I have never tried it so I do not know if it is true or not. Seems logical though.
Jim
'95 E320
'97 Honda CRV
Reply With Quote
  #3  
Old 01-11-2001, 12:22 PM
lipscomb
Guest
 
Posts: n/a
Warped Rotors - Andy 1980 CD

Andy;

According to MB, factory rotors cannot be turned as they are case hardened. The only acceptable approach is to replace them. After market replacemnts are available at about half the cost of the OEMs. I have a pair on my 88 300SEL and I have had no probs.
Reply With Quote
  #4  
Old 01-11-2001, 01:46 PM
Registered User
 
Join Date: Apr 2000
Posts: 460
Buy a torque wrench.

Rotors often warp because someone "repairs" your car and then proceeds to put the wheels back on with the nearest impact wrench. This either applies too much torque to the nut, applies torque unevenly to different nuts, or both. Wheels MUST be bolted down in a criss-cross pattern using a torque wrench. Final torque is probably around 75-80ft/lb, but work your way up from 20 to 40 to 60, etc. I would check with your manual to be sure of final torque specs. Do it yourself too, because I have actaully seen people who didn't know how to use a torque wrench, so even if they say they used a torque wrench, be suspicious.
g
Greg
Reply With Quote
  #5  
Old 01-11-2001, 10:20 PM
Deezel
Guest
 
Posts: n/a
Midas!!!!????

At the risk of offending any one, I have never been impressed by Midas or most any other franchise shop. Under trained, under experienced, commission based maintenance sales, etc. In general, I do not recommend turning brake rotors. Braking turns kinetic energy (moving energy) into thermal energy (heat). The heat needs to be absorbed and dissipated. This is one reason there is a minimum thickness on rotors and drums. You have to have enough steel mass to absorb the heat energy during the stop and then get it cooled off before the next stop. Also, for the cost of turning etc, new rotors a usually worth the money, especially if you are planning on keeping a car for a while.

Good luck!
Reply With Quote
  #6  
Old 01-12-2001, 12:01 AM
Registered User
 
Join Date: Nov 2000
Posts: 168
Thanks for the replies. I live in Washington state. Most of the time I drive my wheels are getting wet from the rain. I took my car to Midas to get an inspection. I wasn't sure how thorough the brake inspection was anyplace else. I am going to get a new set of front rotors. I will also torque the wheels myself according to the manual. I hope the problem goes away after doing that. Thank you, andy
Reply With Quote
  #7  
Old 01-12-2001, 12:45 AM
MikeTangas's Avatar
Senior Member
 
Join Date: Apr 2000
Location: So. Cal
Posts: 4,430
If you need/want a total brake inspection, for peace of mind, go to a good independent Tech or the dealer. Lots of horror stories out there about Midas, my sister took my Dad's truck to a Midas shop for front pads. They ended up talking her into almost $600 (1979 dollars) worth of work. Within 50 miles the right front wheel nearly came off. The "brake specialist" never tightened the spindle nut.

That loose nut caused the new rotor to be eaten up, as well as the bearings and the spindle. The only piece I was able to salvage was the caliper. Another $400.00 in parts and a little bit of my time, the truck was on the road and my Dad was beating on the Midas managers desk. He did get his money back.
__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.
Reply With Quote
  #8  
Old 01-12-2001, 02:41 AM
Registered User
 
Join Date: Jun 2000
Location: Dubai, United Arab Emirates
Posts: 238
If it were my car, it would have without further ado, a new pair of front discs and new pads both sides ! Machining front discs is almost as expensive as new parts and will never recover the original spec. of the discs.
Reply With Quote
  #9  
Old 01-12-2001, 05:17 AM
Ashman's Avatar
Registered User
 
Join Date: Sep 2000
Location: Sherman Oaks, CA
Posts: 4,749
Why don't you check prices on the rotors at the partsshop here.

I could get new front and rear rotors, pads, sensors, and all for very good prices on partsshop here for my car. And believe me, I'll be buying from here when the time comes.

Alon
__________________
'92 300CE - Sold
2004 C240 - 744 - C7 Wheels - Android Radio
2002 C320 - 816 - Sport Wagon
Reply With Quote
  #10  
Old 01-12-2001, 09:27 AM
engatwork's Avatar
Registered User
 
Join Date: May 2000
Location: Soperton, Ga. USA
Posts: 13,648
I made the guy

at the tire store pretty mad yesterday. I took it to a local tire store and had my tires balanced.

First I would not let the guy put it on the rack because there would have been an interference between his rack and a section of the exhaust system. I insisted that he use manual jacks.

Watched in interest as the guy started to try to find a place to put the jack underneath the rear end. He got pretty hot saying that "I know where they need to go", while eyeballing the largest strut that he could see, when I insisted that he put the jacks at the jack points. He finally gave up and walked away when I pulled out the lug wrench and started removing the tires. A Mexican dude came out, took the tires and balanced them (did a good job by the way) and brought them back out to me where I proceeded to remount them. We lowered the jacks and I completed tightening the lug nuts.

The guy cooled off and came back out to the car and understood "whatever it takes to serve the customer". I will go back there the next time I need balancing done. I do not have a balance machine at the house.
Jim
'95 E320
'97 Honda CRV
Reply With Quote
  #11  
Old 01-12-2001, 12:52 PM
Registered User
 
Join Date: Jan 2000
Location: PA
Posts: 5,440
How do you figure turning rotors is as expensive as new ones? I get them done for $6 + tax in upstate NY. I had the fronts done on my '79 300SD and the brakes are as smooth as silk and it was done 27,000+ miles ago. I will agree that if the rotors are warped they may warp again so new are sometimes needed. The rotors can warp form excessive heat so down shift going down long hills.

P E H
Reply With Quote
  #12  
Old 01-12-2001, 03:27 PM
Stevegman
Guest
 
Posts: n/a
By the book?

Turning rotors is a lot less $ than buying new ones. No comparison. But Mercedes says you cannot turn the rotors. I have heard that they need the thickness to absorb heat or they will warp. MB's have STRONG brakes. Lots of heat. You might get away with turning rotors. If hard stops from high speeds is a possibility I wouldn't take the chance.

I have done brake jobs to every car and motorcycle I have ever owned, except my MB because it doesn't need any work done yet. I changed the brake fluid last year. When I bought it there was a terrible brake squeel from one rear wheel. Changed to new MB rear pads and no more problem. The brakes were done at a franchise by the previous owner.

The Mercedes manual clearly states that the rotors cannot be turned. Sure, anyone can cut corners, but for my money, get the right parts. I have had numerous recommendations to use the OEM pads and new rotors. They last a long time. This is no place to scrimp.

Steve
'85 500SL Euro
Reply With Quote
  #13  
Old 01-12-2001, 05:43 PM
Moderator
 
Join Date: Mar 1999
Location: Tucker, Ga USA
Posts: 12,153
refacing rotors

Don't know where everyone got info on MB suggesting that rotors are hardened or that they can't(shouldn't) be refaced, but we do that every day. Benz issued bulletin on subject in 1996 suggesting that under warranty that rotors must be refaced as long as there would be at least 1mm over min material after re-machining. If fact the W220 rear rotors are an almost every day happening!! 2000 Model that is! On early cars the bearing pre-load is important & critical!! On later cars, rotors can be done w/out touching the bearings.
__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator
Reply With Quote
  #14  
Old 01-12-2001, 06:06 PM
Stevegman
Guest
 
Posts: n/a
Wrong again, and I hate that.

Perhaps I misunderstood, but I thought the CD stated no turning. I'll look again to satisfy my curiosity but am sure M.B. DOC is right. I may hate to be wrong, but I love to know the truth. This is one of the reasons that I camp out on this site. Thanks again.

Steve
'85 500SL Euro
Reply With Quote
  #15  
Old 01-12-2001, 10:07 PM
Registered User
 
Join Date: Nov 2000
Posts: 168
I am going to purchase a new set of front rotors and brake pads. I will also torque the wheels myself with a torque wrench according to my owners manual. I appreciate all of the replies. The one thing I am curious about is why only the left rotor has warped and not the right? I'm just worried about going through the expense of new parts and possibly ruining them. Since owning my M.B. and with the help of this site and it's members, I'm am becoming familiar with the DOs and DONTs of M.B. car care. Thanks for you help. I would still like to know why only the left rotor has warped? andy

Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
What caused warped rotors? bhatt Tech Help 14 10-23-2004 11:56 AM
Rear Rotors Warped? Bruce Bonds Diesel Discussion 11 05-15-2004 12:56 PM
warped rotors after 3K!! slowmoe Tech Help 16 07-16-2003 03:15 PM
Rotors warped again.. bhatt Tech Help 5 10-29-2002 08:34 PM
Can someone tell me what are the signs of warped rotors? cossie Tech Help 3 02-15-2002 12:45 AM



All times are GMT -4. The time now is 10:41 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page