Mercedes-Benz Forum banner

1 - 3 of 3 Posts

·
Registered
1985 280SL
Joined
·
254 Posts
Discussion Starter #1
I just finished changing the chain guides on my 1989 560SL. The chain has been recently replaced, timing marks are about one degree off and I found the master link. Spring on the tensioner was obviously very strong and it is very clean, so I assume it was recently replaced as well. I just loosened the tensioner bolts about 1/4" and it gave me enough slack to be able to put the sprockets back on without too much trouble. The guides were almost black and were obviously very old, had Mercedes Benz cast into them. I ordered the new guides along with a pin puller (best price I found was on sleazebay from ewktool, less than $30 shipped and he got it to me in 3 days) and got to work.
Pin puller worked like a dream but I had to do a bit of grinding on the tool to clear the casting on the passenger side head. I used PB Blaster in the ones that were crudded up a bit and it worked great.
I pulled the pins late yesterday afternoon and replaced them with bolts that were a bit smaller and left the guides in place, one at a time.
I cleaned the pins thoroughly, put them in a baggie and put them in the freezer at home. I filled a small thermos with ice and put the baggie with pins in it and headed to the shop this morning to finish the job. I only pulled each pin as I needed it to keep the remainder cold.
I found that I could push each frozen pin in almost all the way with just my thumb, up to the point where only about 1/4" remained. This last bit was easy to tap in with a small hammer. I used a small socket to finish the job and countersink the pins to their original position.

The only issue I encountered was that I moved the cam back a bit on the driver's side head when I tapped the sprocket back into position. None of the cam lobes had slipped off of the followers, so it was easy to pull the cam forward by tightening the sprocket bolt. I didn't see anything else that could have gotten damaged by this but if this triggers a red flag for any readers, please let me know. We finally got the bastard valve cover with new gasket back onto that side, I'm sure hoping I don't have to get back in...

Hope this helps someone that was not looking forward to tapping the pins back in place in an area with restricted movement.
 

·
Premium Member
1976 450SL
Joined
·
450 Posts
Just changed mine as well, though I had lots of space - all the engine ancillaries, A/C condenser and radiator are out of the car, but it's good to know there's a trick to try if I have to go back in there again...

I bought the Baum tool from an Ebay seller, but the adapter broke on the very first pin :-( I then made myself a tool, using a steel bush (similar to a socket), and grade 10 nut, bolt and some fender washers. That worked very well on the right hand head (where the area around the pins is flat), but was a challenge on the left hand head - until I realized that I could use the 'outer' part of the Baum tool instead of the bush - that has a cutout that fits the various locations very well. My pins were very tight - as each one started to move there was a very definite 'crack' from my jerry rigged tool.

I think the Baum tool adapter wasn't hardened properly. I had to drill the end of broken off adapter out of the pin (which was still in the head), and it drilled out very easily (phew), seemed very soft compared to most tool steel. I've asked the seller if he can supply a replacement adapter.
 

·
Registered
'79 450SL, '04 CLK200 convertible; former A124, W210, A209.
Joined
·
1,507 Posts
Great tip on freezing the pins, clever application of physics ? when replacing my sprockets the cam moved a tiny bit as well, but like you I put it back in its spot. The marks aligned afterwards and car is running fine, so fear not.
 
1 - 3 of 3 Posts
Top