Replacing Rack dampener pin - Page 2 - PeachParts Mercedes-Benz Forum

TheDon · #16 06-08-2008, 11:45 AM

Quote:

Originally Posted by dieseldan44

You need a 14 mm and 16mm open end wrenches I believe.

-Get the car to hot idle, shut the car off.
-There is a locknut on the old pin. Loosen this a couple turns.
-With the wrench, and then your fingers unscrew the old rack damper pin. A valuable technique: Straddle the oil cooler line with your thumb and middle finger to make the turns. This makes the whole procedure SOOO much easier. I laughed a cosmic laugh when I realized this.
- Remove and observe.
-Take some of the oil off the old pin and put a little on the new gold pin.
-Screw pin into the IP until you feel a little resistance.
-Turn the car on.
-Now it's time to tweak. Back out the screw until the engine really lopes. You'll know when youre there.
-Now screw in a couple turns, to right after it stops loping. It will not get much smoother going in further, it supposedly will be harder to start.

This improved my hot idle quite a bit. I got a gold damper screw off a junkyard car. There's an article that ive probably paraphrased pretty much at mbz.org IIRC.

Good luck!
dd

I think I am screwed, mine will not turn by hand, even after seriously loosening the lock nut.

#17 06-08-2008, 12:07 PM

It won't because the o-ring is acting like a wedge in the threads.

TheDon · #18 06-08-2008, 12:30 PM

I've spent the last, what 20 minutes fumbling with it... no matter which way I go with the lame, short 12mm wrench, It will not back out...

I hate the rack dampner bolt... I can't get enough throw on the wrench to back it out at all.. Lowes didn't have a long enough 12 mm, they sold one that was shorter than the craftsman I already have! I'm not driving 45 minutes for a bloody wrench that sears probably wont be able to find for me. I'll have my mechanic do it.

#19 06-08-2008, 08:18 PM

Get a gear (ratchet) wrench for about $12. The 12mm gear wrench also makes changing glowplugs much easier.

TheDon · #20 06-08-2008, 08:21 PM

I got it out without the gear wrench, But I would like some in the usual sizes.

joro · #21 06-30-2008, 08:47 PM

can someone please post a picture of the rack dampner and where it is on the ip.
thanks

1983/300CD · #22 06-30-2008, 09:06 PM

Start looking in the space between the IP and the oil filter. It's screwed into the IP, in its rear. Can't miss it.

RML · #23 07-01-2008, 12:20 AM

Quote:

Originally Posted by Dewhite2485

Im new to MB diesels, what is this pin what does it do, why does it cost so much and where is it

I was talking to the indy I go to when a job is over my head. He told me it controls the fuel pressure, and if I decide to play with it, mark where it was set so I can get it back there if needed. They set the pressure at the factory. From what I have read, the original pin had a weak spring and the replacement corrects that problem. So it sounds like if you are getting one from the junkyard, make sure it is the replacement. For the price, time invested in getting it from the junkyard, and risk of it being worn out, personally I would go with a new one. I have been burned too many times with trying to save a few bucks at the junkyard on a critical part. Heck, it costs less than a fillup now.

Here is one I found with some info: http://**************.com/search/node/rack+damper

If anyone has had problems with this parts source, please let me know. I looked at Fastlane's parts catalogue first but did not see it listed.

Diesel911 · #24 07-01-2008, 01:45 AM

Quote:

Originally Posted by RML

I was talking to the indy I go to when a job is over my head. He told me it controls the fuel pressure, and if I decide to play with it, mark where it was set so I can get it back there if needed. They set the pressure at the factory. From what I have read, the original pin had a weak spring and the replacement corrects that problem. So it sounds like if you are getting one from the junkyard, make sure it is the replacement. For the price, time invested in getting it from the junkyard, and risk of it being worn out, personally I would go with a new one. I have been burned too many times with trying to save a few bucks at the junkyard on a critical part. Heck, it costs less than a fillup now.

Here is one I found with some info: http://**************.com/search/node/rack+damper

If anyone has had problems with this parts source, please let me know. I looked at Fastlane's parts catalogue first but did not see it listed.

Your Indy is not correct concerning the Rack Damper Bolt controlling the fuel pressure. The fuel injection pressure is controlled by the Pop Pressure of each of your injectors and the pressure from the Fuel Supply Pump is controlled by the Overflow valve on the side of the Fuel Injection Pump Housing.

RML · #25 07-01-2008, 06:52 AM

Quote:

Originally Posted by Diesel911

Your Indy is not correct concerning the Rack Damper Bolt controlling the fuel pressure. The fuel injection pressure is controlled by the Pop Pressure of each of your injectors and the pressure from the Fuel Supply Pump is controlled by the Overflow valve on the side of the Fuel Injection Pump Housing.

Well, so much for his opinion. From the shape of it, like a needle valve, it looks like it would control flow of fuel somewhere along the path of fuel delivery.

#26 07-01-2008, 07:03 AM

The rack damper is exactly what its name suggests, it dampens the rack. Its a mini shock absorber that keeps the fuel rack from vibrating at idle and making the engine shake.

RML · #27 07-01-2008, 07:11 AM

Quote:

Originally Posted by ForcedInduction

The rack damper is exactly what its name suggests, it dampens the rack. Its a mini shock absorber that keeps the fuel rack from vibrating at idle and making the engine shake.

Thanks for the explanation, Forced. That certainly points to the Rack Damper as the culprit for why my engine shakes at idle. Sometimes it does, sometimes not.

joro · #28 07-01-2008, 10:34 AM

A nice big picture would help us newbies,and a part number too,thanks.

RML · #29 07-01-2008, 08:36 PM

Quote:

Originally Posted by joro

A nice big picture would help us newbies,and a part number too,thanks.

Try this link: http://www.peachparts.com/shopforum/attachments/diesel-discussion/42618d1174877713-so-what-does-rack-damper-bolt-617-actually-do-rack-damper-gold-silver.jpg

toomany MBZ · #30 07-05-2008, 05:40 PM

Try part # 0000742674.
In the pic, the top one, gold color, are the new ones, they have a stronger spring. It does not come with the lock nut, or "o" ring, the latter of which is not on either one.