Gentelmen

I am trying to remove the pin that the chain tensioner rail pivots on. The manual says this is a slip fit and should just slide out by canting a bolt or screw driver in the hollow pin and pulling. Well it probably was a slip fit 18 years ago, but today it is a fit with lots of coked up oil welding it in place. Does anyone have any tips for getting this out. I may try warming the block tonight with a heat gun.

John Roncallo

I am doing the exact same thing on my 84 500sl. I soaked everything with PB blaster first. They are designed to be pulled out with a slide hammer but it is a little tight. I purchased a pin puller on ebay that works great. It has the 6mm thread to screw into the pin then a larger bolt working against the body to pull the pin out. It was $40.00 with the shipping. The real danger when pulling these pins is stripping out the threads. I read the posts about using a bolt and socket to get them out but decided to buy the tool. The real trick is to get the threads cleaned out with penetrating oil.

Every time I start to pull one, I hold my breath. Murphy has a habit of moving in when ever I start one of these projects

Hope this helps

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I really gets fun when they all don't run

84 500SL
99 Jeep XJ
93 Jeep YJ
03 Custom Softail

I just reread you post and realized you were talking about the tension tail, not the guide rail. Yea, it is supposed to slide out. I would keep on soaking it.

__________________
I really gets fun when they all don't run

84 500SL
99 Jeep XJ
93 Jeep YJ
03 Custom Softail

Here is one idea on how to get the pin out, it is after the instructions on how to remove the guide pins Number 14

http://www.dianasmercedes.com/TechnicalArticles/TopGuideRail.htm

__________________
I really gets fun when they all don't run

84 500SL
99 Jeep XJ
93 Jeep YJ
03 Custom Softail

I got it out. I actually considered the idea in the web sight you supplied but I used a 3/8-16 tap instaed. I had soaked the area with PB and then inserted the tap. I rotated the tap until it dug in and started to rotate the pin. Then I soaked it again and the tap had gone in far enough that I could pull on it. But it would not come out with just pulling so I continued to pull on the tap as I rotated it making sure not to put any forward preassure on the tap and it rotated out came out. The pin had one slight burr in it less than 1 thread deep when I got it out. So I just cleaned it up with a die grinder and re-used it.

It was interesting to see just how brittle these nylon linings get when thay are 18 years old and have 120K miles. When I went to pry the old lining off the aluminum guide rail backing it instantly snaped the retaining ear off with very little prassure. It certainly makes me concerned about the lower rails.

John Roncallo

I recall that it was very tricky, even with a very clean engine. I would up doing it with a machinist size drill bit that was very close to the ID of the bearing.

Installing it is also fun. In this case, I used a slightly smaller drill bit, the smooth end, as sort of a "feeler guide" for the arm, and then I coaxed the bearing in. The bearing has beveled edges which helps, as does a lot of clean oil.

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86 560SL
With homebrew first gear start!
85 380SL
Daily Driver Project

http://juliepalooza.8m.com/sl/mercedes.htm

Since this is being brought up, I'm about to purchase an M117 for my 420 here. The motor is from an early '86 car (probably built late '85) with about 111K mi. Turns over well and all.

Anyway, how feasible is it to replace the lower guides also? My 420's motor met its demise due to two broken upper guides.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Yeah, the nylon backing which rides against the chain is very brittle, but it wears well on the chain, perhaps better than the old rubber types. The pivot pin(s) are just a machine fit, as you say, but once you get them rotating a bit, as you did, you're more than half way home. Using a bolt and washers (larger than the o.d. of the pin flange has worked for me (and other's)). As one member said, a slide hammer is the easiest way, but you may have to remove the radiator, which is a snap on my 220D, but don't know about your model.

Very easy with the engine out of the car. Just be carefull with the front portion of the head gasket that also covers the timing chain cover.

John Roncallo