Rack Dampener - PeachParts Mercedes-Benz Forum

dieseldaddy · #1 04-21-2002, 04:13 PM

OK, what did I do wrong??

First of all, let me say that I have FINALLY learned the "If it ain't broke...DON'T FIX IT!!" rule.

My 1981 300tdt had a pretty rough idle when warm. Nothing major, but it bugs me. (i.e. "IT AIN'T BROKE")
I did several searches to see what there was out there, and the concensus was that I could easily remedy this by 'adjusting' the Rack Dampener.

So, I locate mine. 14mm hex and 12mm hex.
Here is what I did with the car idling:
1. Loosened the 14mm (set scerw?)
2. Tightened 12mm just about 1/4 turn.
3. Smiled from ear-to-ear as the engine settled right down (almost sounded like it was idling a little faster...) Almost didn't sound like a diesel!
4. Pulled on the linkage to see where she settled back down to and she stalled.
5. Started back up hard. I mean real hard as if it were 15 degrees out and no glow plugs working! (was actually about 70 degrees that day). Puffed HUGE clouds of black smoke.
6. Backed outta my garage to test drive and stalled when put into gear.
7. Restarted fine and continued my test drive to the corner about 100 yards when it stalled again.
8. Stalled at next stop light. (You get the picture?)

So I gave up and limped home where she stalled turning into my driveway. Loosened the 14mm again and loosened the 12mm to where *I thought* it was in the first place. Restarted the car and things were back to normal. *NOT*
The engine sounded just like it did b4 I messed with it in the first place, BUT it still kept stalling on me! !@#$!^$#@#

SO, I spent a ton of time this afternoon (instead of watching the NBA playoffs, argh...) turning the 12mm slightly back into place then taking her around the block, repeat several times and FINALLY think I have it back to normal which is rough idle but NO STALLING.

What the heck did I do wrong? I only turned the thing 1/4 turn?!?!

Any advice is appreciated as my wife is hesitant about driving it now.

P.E.Haiges · #2 04-22-2002, 01:21 PM

Dieseldaddy,

Now you made me afraid to try to adjust mine. I hope someone comes up with an answer for you.

P E H

dieseldaddy · #3 04-22-2002, 02:22 PM

OK, I have been thinking that the 14mm is not a set screw but the actual connection to the rack. So by loosening THAT thinking that I have to to tighten the 12mm, I may have caused a leak of some sort.

BUT, I have since tightened it back up and I believe that I returned both the 12mm and 14mm to their original locations based on engine idle/sound/feel.

...And I still stall. Not as often, but when I first put the car into gear, or even the first time I ramp up RPMs and come back down, for instance stopping at a stop sign.

I have a sneaky feeling that my wife has experienced the stalling today as she was supposed to call me when she finished her errands, and that was over 3 hours ago.

Luckily, we have a comfy couch for me to sleep on!

I am thinking of chanign my screenname to "dieseldummy".

'79 Super Turtle · #4 04-22-2002, 11:21 PM

My experience has been that you have to rev the engine with every small turn of the bolt. It's not the "idle" it's the revving that will tell you if it is adjusted right. When you rev it and it does not "drop out" at the end of the rev, a smooth rev, then it is adjusted correctly.

Holson Adi · #5 04-22-2002, 11:32 PM

Does it have to be revved and then released? When you say a smooth rev, do you mean that after it's revved and released, the engine's rpm just sits at a set idle? Instead of falling below the idle first and then floating back up to the idle?

Is that it?
I guess mine's adjusted pretty badly.

'79 Super Turtle · #6 04-23-2002, 12:14 AM

The "rev" will have a dead spot in it, and not come back to normal idle correctly...i.e. "stalling" when out driving.

Holson Adi · #7 04-23-2002, 12:26 AM

hhm.. I wonder why my car still runs fine despite the fact that my rack damper screw is all the way in...

Maybe I should just take it to the dealer and have them set that + idle + the i.p start of delivery...

'79 Super Turtle · #8 04-23-2002, 12:32 AM

I have no idea, but I love CD's, hope to have one someday.

It must be one of those Mercedes mysteries?

I won't even go into the whole "worn out adjustment bolt" phenomenon, that was always lost on me. Perhaps your bolt is worn out! Let's just say it is!

MikeTangas · #9 04-23-2002, 12:47 AM

other than to say "Hi Patsy, long time no see".

'79 Super Turtle · #10 04-23-2002, 01:05 AM

Well thanks Mike and Bill! I missed you too, and the forum, I'll have to check in more often, surely there is something wrong with my old super turtle, I'll have to give her a "once over" tomorrow! She never complains, unlike me...

Thanks!

can-do · #11 04-23-2002, 03:25 AM

Hi Patsy,

As everyone else has posted, I've missed your input as well. I sold the '80 300TD and it now resides in your home town from a buyer that came down to make the purchase a little over a week ago. So if you see a gloss black station wagon in town that seems new to you, it was mine.

I think the rack dampner bolt that everyone keeps trying to adjust that is all the way driven into the IP housing just needs to be replaced, as mine is in the same condition, and was mentioned on a previous post that the spring becomes weak and the end becomes worn or hammered and basically needs to be replaced with a new one to adjust it out correctly. You can find it at Fastlane under fuel injection and the item is the EHA valve, who knows why, but that's the part you need and it's the new hardened bolt that will hopefully not wear as quickly as the one you replace. I believe mine to be original in my '84 300SD turbo but I will renew it with a new one to rid myself of the occasional off beat idle that I sometimes experience.

Nice to hear from you Patsy,

Charles

dieseldaddy · #12 04-23-2002, 08:29 AM

I will order a new EHA valve from Fastlane, as I believe mine is original as well.

Thanks for all your input. WHat I was not doing was reving the engine after every turn. I only did that the one time...and it stalled.
From what you have said, that means that it was tightened too much?

Is there any trick to removing/installing the EHA valve? Seems pretty straight forward. Should I clean anything our while I am there?

Seems like a pretty tight fit...

dieseldaddy · #13 04-23-2002, 08:32 AM

...that I did not mention is to be careful when test driving after adjustment.

Once I *thought* I had it smoothed out, I took it for a spin and the accellerator STUCK! Not cool when you are already going 35 in a 25 past the police station...
This was not a happy feeling.

I would have to quickly punch it to the floor for it to release.

Just a precaution...

'79 Super Turtle · #14 04-29-2002, 10:36 PM

Charles, I can't believe it, but I just had your dearly beloved black TD pass by me on University Avenue here! I saw her coming, and when I saw the chrome lower side panels, I just knew it was the old girl from the photos you sent me! I couldn't believe it, I blew her a kiss for you!

I wish I had bought her! But it's fun knowing she has my old shut-off valve on her! It's a small world after all.

Take care!

can-do · #15 04-30-2002, 08:16 PM

Greetings Patsy,

Yeah, it was most likely my past Baby, not too many out there with lower panels that shine back at you let alone TD's in general. The neighbors were starting to think I took up collecting them so I thought I better sell one of them seeing as I can only drive one at a time anyway and the SD suits me better. If you meet up with it again, honk at her and freak the new owner out wondering what's going on.

Charles

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