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 > Tech Help

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 11-02-2009, 03:22 PM
scottmcphee's Avatar
1987 w124 300D
 
Join Date: Mar 2008
Location: Edmonton, Canada
Posts: 1,539
Pulling off speedometer needle, 2 spoons, ya right..

Tried this, using the much suggested two spoons method to get under the needle to pry it off the speedometer. It's hard to tell how much leverage you're applying to that needle, and when something when POP and the needle plus its shaft plus some of that coil spring comes up through the hole you think softly in your mind, "oh *****". Snapped the thin little shaft that goes to the back of the gauge. No way that's going back together.

Lucky for me, I had a spare cluster or two hanging around so in goes a new speedometer gauge into the cluster. Bummer now that I have to do math now to arrive at the actual miles on the car.

I actually daydreamed about swapping out the mechanical gauge for an electronic one and dialing in the correct ODO in the process.

Anybody play with any aftermarket type speedometers? Maybe tuck away the original one under the dash, just so that it could drive the pulse counter for the brake control system, but use that pulse to also drive the electronic speedometer..

__________________
Cheers!
Scott McPhee

1987 300D
Reply With Quote
  #2  
Old 11-03-2009, 10:56 AM
Registered User
 
Join Date: Sep 2009
Location: Great State of Texas
Posts: 440
Just out of curiosity, why did you want to remove the speedo needle? Everything I've read says "don't touch the needle".
__________________
A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.
Reply With Quote
  #3  
Old 11-03-2009, 03:21 PM
scottmcphee's Avatar
1987 w124 300D
 
Join Date: Mar 2008
Location: Edmonton, Canada
Posts: 1,539
Two reasons: I wanted to swap faceplate from US (miles and km) to one for Canada (km only). Far fewer numbers on the faceplate, cleaner look. Plus the dial was off (reading slower than I was actually traveling) so I wanted to adjust it because it cost me a speeding ticket to clue in.

In the end I just took the whole Canada car gauge (with higher mileage reading on it ) and mounted it in the cluster. I had the needle off that one already. Now, putting it all back together my speed is off and it reads faster than I'm actually going. As measured using GPS.

I know tires have a lot to do with % error on speedo for this car. Just swapping from my summers to winters made about a 6% difference in accuracy. Better accuracy on the winters. They're all 195/65R15 but obviously the outer diameters are different.

In new cars, dealers can dial in a correction factor to the ECU. To accomodate gear ratios and tire choice. Not this car. Got me to thinking, why not fit a modern electronic gauge in my car that converts a pulse stream to current and deflects needle accordingly. There's solutions out there, Dakota Digital is one such vendor, for the electronics, but their gauges are all digital (go figure). I don't want digital I prefer analog dial. No modern car has a speedo cable from the tranny coming up to the cluster any more to move gears and clockworks for speedo and odo. It's a wire carrying pulse count.

Adapters are offered to take old car speedo cable and screw an end onto it to get pulses. But Mercedes has a pulse counter there to support braking system, I believe, maybe engine too.. So, I'd keep the cable on the factory gauge, stash it under dash, and split pulses off it. I am capable of building such electronics myself, just wanted to know if anybody has scouted nice dials that fit stock cluster housing. Could come from OEM or aftermarket gauge, so long as it fits the space, and it's electronic, I can make a driver for that needle.
__________________
Cheers!
Scott McPhee

1987 300D

Last edited by scottmcphee; 11-03-2009 at 03:26 PM.
Reply With Quote
  #4  
Old 11-04-2009, 12:30 AM
pawoSD's Avatar
Dieselsüchtiger
 
Join Date: Oct 2004
Location: Grand Rapids, MI
Posts: 15,437
You can fairly easily change the numbers on the odometer to reflect your car's mileage by undoing the gear drive and changing them manually. Or, if it has less showing than the car has, hook it up to a fast drill and let it read 120mph for a while.....then stop when its to the right miles.
__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 109k - mine - (OC-112,500)
'17 Metris(VITO!) - 29k - wifes (OC-34k)
'09 Sprinter 3500 Winnebago View - 61k (OC - 63k)
'13 ML350 Bluetec - 82k - dad's (OC-86k)
'01 SL500 - 98k(km) - dad's (OC-94,000km)
'16 E400 4matic Sedan - 132k - Brothers (OC-139k)
Reply With Quote
  #5  
Old 11-04-2009, 03:34 PM
scottmcphee's Avatar
1987 w124 300D
 
Join Date: Mar 2008
Location: Edmonton, Canada
Posts: 1,539
I tinkered with idea of trying to match up the ODO to reality. The one I replaced it with has more showing, so it would have to go backwards. I found when you spin the gear backwards (as if you're going in reverse) the ODO it will reduce mileage only up until the "3" displays in the rightmost digit position. It won't go any lower. Something starts free-wheeling at that point, so it seems at most you can only reduce an ODO by maybe 9 miles. I wondered if this was just my sample, or if this was general case?

It kinda makes sense if it is a design feature because most people 1) don't care about ODO reduction while backing up, and 2) don't drive backwards continuously for more than a little bit, and 3) prevents fraudsters from burning out drills to make false readings.

I looked at ways of lifting or accessing gears and tumblers directly, but the unit is all packed in there quite nicely... and many approaches would in fact require removal of the dial and faceplate, and possibly lifting the plastic gear cage up out of the metal housing... and ... given my recent needle breakage and feeling low on spare speedometers, I thought not.

But if you want to post a helpful how-to-rollback-your-odometer DIY page for Mercedes owners, I'd read it and try. So would said fraudsters so maybe not a great idea. PM me instead!
__________________
Cheers!
Scott McPhee

1987 300D
Reply With Quote
  #6  
Old 02-04-2013, 12:46 PM
Registered User
 
Join Date: Apr 2011
Location: SF, CA, USA
Posts: 935
here is a project to use the W126 speedo; get your hands on one of these finely printed cards, that might be all that's necessary...

http://www.benzw****.org/forums/w123-e-ce-d-cd-td/1695755-my-w126-w123-speedo-conversion-dont.html
Reply With Quote
  #7  
Old 02-05-2013, 12:56 PM
Registered User
 
Join Date: Dec 2003
Location: Palm Springs, CA
Posts: 782
Don't have a clue as to where you could buy one, but there are "pointer pullers" used the the calibration and repair of pressure gauges. All Metrology labs have a collection of these. You might try "googling" pointer pullers. I've used them. They work perfectly.
Anziani

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 12:09 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2022, 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