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 05-19-2019, 05:30 PM
JHZR2's Avatar
Registered User
 
Join Date: Jan 2002
Location: New Jersey
Posts: 3,966
Ran my 300CD for the first time in ~7 years...

Bought my 300CD in CA, drove it cross country, drove it quite a bit around on road trips, etc., then got caught up in figuring out window regulators, parked it in my garage, kids came and... Now Im trying to get it back going.

Had changed out the coolant to G-05...

Diagnosed a leaky schrader, so changed it...



Got tires mounted on my CalChrome Clear'ed 15" Bundts:



And went for a drive...

The AC charge is insufficient, and it was 86 out, so it was OK but not cool in the cabin. I can fix that.

There is a sound I hear at 40-50 but nowhere else, will need another thread on that...

There is no heat. Tried running the car with defrost on when filling, no dice. I dont particularly care about having heat besides wanting active chemistry in the heater core.

So the issue...

Driving along, under harder braking, like a more rapid stop at a red light, it felt like if I applied the brakes it was OK, but let off there was a front end clunk. Like something is loose in the front end.

Now remember that when I parked it, Id drive the car anywhere. Literally did. Ran great, nice AC, etc. I did stuff to it, but never encountered this. Almost feels like the suspension is shifting forward and backwards a tiny bit when doing this braking action...

So I got home and checked the wheels - left front wasnt able to be touched. Immediately jacked the car up, could barely touch the lugs, got them off with my impact. Got out the IR camera.





(ouch!)



This is it in real life. Nothing could be touched 15 minutes after removing the wheel.



For reference on the other side...



Which still seems a bit hot to me...



I know, not the exact same spot on the rotor, but it was much cooler overall.

So... I guess it means seized caliper, and need to re-do the entire brake system. Not a big deal.

But my questions are now:

1) When braking, it felt like something in the front suspension was shifting back and forth very, very slightly. Maybe it was a seizing of the pads to the rotor? nothing on the front is loose, I had rebuilt most of the front suspension, and the steering on this car is tighter and better than any W123 or 126 Ive ever driven, including my 240D with 73k miles. Is there something else I should check given that the typical play and shake tests yield nothing, and it only happens after a hard stop?

2) We drove all over doing errands. Probably 30 miles, six startup and shutdowns, etc. All was perfect. But the last leg, the last 2 miles just in town, slow to get home, the braking got softer in the pedal, and after I pulled up in my driveway and tried to shut the car off, it hesitated to shut down. Im not sure that the continuously softer pedal and the difficulty shutting down were coincidental. But Im not sure the seized/hot caliper is the same error as if there is a brake booster/vac issue. Any thoughts?

Thank you for any recommendations!
__________________
Current Diesels:
1981 240D (73K)
1982 300CD (162k)
1991 350SD (113k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
Reply With Quote
  #2  
Old 05-19-2019, 06:39 PM
Registered User
 
Join Date: Jun 2004
Location: West of Ft. Worth. TX
Posts: 4,150
When I encountered something similar, re-torque of the caliper bolts seemed to resolve the "shift".
__________________
Sam

84 300SD 350K+ miles ( Blue Belle )
Reply With Quote
  #3  
Old 05-19-2019, 07:42 PM
Registered User
 
Join Date: Jun 2015
Location: PA
Posts: 392
Quote:
Originally Posted by JHZR2 View Post

2) We drove all over doing errands. Probably 30 miles, six startup and shutdowns, etc. All was perfect. But the last leg, the last 2 miles just in town, slow to get home, the braking got softer in the pedal, and after I pulled up in my driveway and tried to shut the car off, it hesitated to shut down. Im not sure that the continuously softer pedal and the difficulty shutting down were coincidental. But Im not sure the seized/hot caliper is the same error as if there is a brake booster/vac issue. Any thoughts?

Thank you for any recommendations!
Pull off the main vacuum line connection that screws onto the vacuum pump. Fish around in there and see if any debris or the vacuum check valve broke off. That can clog up and reduce vacuum.
__________________
'80 300SD - '83 240D - '00 E55 AMG - '97 Land Rover D1
Reply With Quote
  #4  
Old 05-19-2019, 09:25 PM
Father Of Giants's Avatar
Registered User
 
Join Date: Feb 2017
Location: Newport News, Virginia
Posts: 1,413
Man that's HOT, you think the bearings and grease are ok?
__________________
1986 Mercedes 300SDL Black - 320,000 miles. Out of retirement

1997 E300 Captain Slow - 218,000 miles

2000 Mercedes E320 Black - 136,000 miles - New daily driver.

Don't forget to grease the screw and threads on the spring compressor.
Reply With Quote
  #5  
Old 05-19-2019, 09:31 PM
vwnate1's Avatar
Diesel Dandy
 
Join Date: Nov 2005
Location: Sunny So. Cal. !
Posts: 4,383
That brake rotor is such a pretty shade of blue.....

Time to look for restriction in fluid back flow, might well be a hose .

Don't forget to re pack the wheel bearings .

Nice looking Coupe ! .
__________________
-Nate
1982 240D creampuff 370,000 miles
1978 300CD back from the dead&1980 300CD ~ SOLD
1984 300CD KEEPER ! 440,XXX miles
1984 Euro 300TD Fully optioned SWMBO's
1974 350SLC 4 speed stickshift SOLD & missed
Krazy Kommie Ural Motos (3)
BMW Moto R60/6 Barn Find, 8,000miles
1959 VW #113 Deuxe Beetle, 36hp engine, stock
Junk, Rust, Arthritis, Crushed Spine,Broken Neck&Back
Memories, Peace Of Mind
facts & reality don't change because you can't handle them
Reply With Quote
  #6  
Old 05-20-2019, 12:20 AM
JHZR2's Avatar
Registered User
 
Join Date: Jan 2002
Location: New Jersey
Posts: 3,966
Quote:
Originally Posted by SD Blue View Post
When I encountered something similar, re-torque of the caliper bolts seemed to resolve the "shift".
Arenít those single use bolts? I will give that a try for diagnosis purposes.


Quote:
Originally Posted by HarvAMG View Post
Pull off the main vacuum line connection that screws onto the vacuum pump. Fish around in there and see if any debris or the vacuum check valve broke off. That can clog up and reduce vacuum.
I had to move cars in the driveway so I pulled it out and then back in. The booster/pedal is still very soft, feels more like my Chevy pickup then any w123 Iíve owned. Not clear what that means... but the engine did shut off as normal when I did that vehicle exchange. So I suspect that it may have been my pumping the pedal that affected shutdown due to the firm, pumping motion Imapplied to see if I could get my pedal harder again.

So it begs the question, what made my brake pedal go soft and stay that way?
__________________
Current Diesels:
1981 240D (73K)
1982 300CD (162k)
1991 350SD (113k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
Reply With Quote
  #7  
Old 05-20-2019, 04:12 AM
Stretch's Avatar
...like a shield of steel
 
Join Date: Sep 2009
Location: Somewhere in the Netherlands
Posts: 14,453
My vote is for a stuck brake piston - though it is always best to check fixings / mountings / rubber parts if a car has been sitting for a while.
__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!
Reply With Quote
  #8  
Old 05-20-2019, 07:23 AM
vstech's Avatar
DD MOD, HVAC,MCP,Mac,GMAC
 
Join Date: Mar 2006
Location: Mount Holly, NC
Posts: 26,301
Clunk braking is usually guide rod bushing/ mount
__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
Reply With Quote
  #9  
Old 05-20-2019, 07:55 AM
JHZR2's Avatar
Registered User
 
Join Date: Jan 2002
Location: New Jersey
Posts: 3,966
Quote:
Originally Posted by vstech View Post
Clunk braking is usually guide rod bushing/ mount
I know. Thatís my consideration/concern.

Not really sure how it could go bad while sitting, but that will be something to pursue. Iíd suspect that if one brake is dragging like it is, perhaps the tire front end has a bit of misalignment or pull on it due to that, which might then make a part that is marginal behave worse. Not looking forward to that job if it is required...

Iím going to re do all the brakes and go from there when I have time...
__________________
Current Diesels:
1981 240D (73K)
1982 300CD (162k)
1991 350SD (113k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
Reply With Quote
  #10  
Old 05-20-2019, 09:08 AM
tyl604's Avatar
Registered User
 
Join Date: Feb 2008
Location: Atlanta, GA
Posts: 3,211
I agree that the heat problem is probably a sticking caliper. Had the same problem on my '81 300SD; changed it out and problem resolved. Before that I could take a short drive and the wheel would heat up so much I could not touch it. Other three wheels would be fine.
Reply With Quote
  #11  
Old 05-20-2019, 06:35 PM
Registered User
 
Join Date: Oct 2012
Posts: 4,733
Some of your difficulties are probably directly related to that stuck caliper.
Reply With Quote
  #12  
Old 05-21-2019, 01:20 AM
JHZR2's Avatar
Registered User
 
Join Date: Jan 2002
Location: New Jersey
Posts: 3,966
Yes, the caliper is my first job to fix, potentially before I even do a real brake job.

I’m not quite seeing how I can get the clunking feeling upon brake pedal release without something else in the front suspension being off, but not sure what it could be either.
__________________
Current Diesels:
1981 240D (73K)
1982 300CD (162k)
1991 350SD (113k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
Reply With Quote
  #13  
Old 05-21-2019, 11:20 AM
vwnate1's Avatar
Diesel Dandy
 
Join Date: Nov 2005
Location: Sunny So. Cal. !
Posts: 4,383
Exclamation Work Smart

And do the entire job in one go, it'll be faster, easier and cheaper plus a better job in the end .
__________________
-Nate
1982 240D creampuff 370,000 miles
1978 300CD back from the dead&1980 300CD ~ SOLD
1984 300CD KEEPER ! 440,XXX miles
1984 Euro 300TD Fully optioned SWMBO's
1974 350SLC 4 speed stickshift SOLD & missed
Krazy Kommie Ural Motos (3)
BMW Moto R60/6 Barn Find, 8,000miles
1959 VW #113 Deuxe Beetle, 36hp engine, stock
Junk, Rust, Arthritis, Crushed Spine,Broken Neck&Back
Memories, Peace Of Mind
facts & reality don't change because you can't handle them
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




All times are GMT -4. The time now is 09:50 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page