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 ShopForum > Technical Information and Support > Tech Help

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 09-02-2000, 10:11 PM
Registered User
 
Join Date: May 2000
Posts: 50
The cruise on my '80 450sl (45,000 miles) seems to work fine with one exception. It continually loses speed over a long time. As an example I will set it at 65 mph and over the next 50 miles it will be down around 62 mph. Once I speed up and reset it it does the same thing. Not sure how far it will drift down but it is a bit annoying.

Is there a setting or potentiometer somewhere on the control unit that will get it to stop drifting like this?

------------------
Jim Loseke
1980 450Sl
Reply With Quote
  #2  
Old 09-03-2000, 12:13 PM
Moderator
 
Join Date: Mar 2000
Location: Gainesville FL
Posts: 6,844
This is one of the most common failures of the early VDO controllers. We have fixed many of those controllers through two techniques; first resoldering the PC board and second replacing the capacitors. The capacitors are involved in the memory/timing sections.

Many of the rebuilders of these units add potentiometers to trim that function and a couple others; point of set and length of feedback loop.

I would also adjust the slack in the control cable as these are often very loose, which places the actuator at its end of stroke; where it has less control.

------------------
Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician
Reply With Quote
  #3  
Old 09-03-2000, 03:01 PM
Registered User
 
Join Date: Apr 2000
Posts: 166
Steve,
Is there any source of information on how to add the potentiometers to these circuits?

During the "Warranty Days" of my car, the problem was supposedly cleared up by adding temperature compensating components to the circuits. It helped but didn't completely solve the problem.

TIA


------------------
Ted
1979 240D
160,000 miles
Reply With Quote
  #4  
Old 09-03-2000, 08:39 PM
Moderator
 
Join Date: Mar 2000
Location: Gainesville FL
Posts: 6,844
Years ago (about 12 I think)someone wrote a technical manual for that controller and it was printed in a "Star" magazine article. A customer brought it to me and we have used it to diagnose those controllers ever since in our radio/electronics room. Last time I saw the document it had a big section eaten out of the text (mice, I think).

I don't know if they have archives, but if any of you super sleuths can locate it, I would like another copy.

In the mean time I will see if I can locate whats left. Unfortunately my brother has the info in his hard head instead of his hard drive so I don't think its recoverable at this end.


------------------
Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician
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
Cruise control on C-Class 1997 merclover2004 Tech Help 5 04-13-2004 08:42 AM
Cruise control again Mercedes Man Diesel Discussion 4 01-25-2003 09:25 PM
82 300SD throttle linkage and cruise control waybomb Diesel Discussion 0 12-28-2002 06:52 PM
1980 450sl climate control problem michael rybikowsky Tech Help 14 01-24-2002 03:37 PM
Adding cruise control to '79 450SL Mark Herzig Tech Help 0 10-16-2001 11:16 AM



All times are GMT -4. The time now is 01:25 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2011 Pelican Parts - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page