PeachParts Mercedes-Benz Forum - A Tale of Two Seals--Replacing Rear Window Rubber

This post describes my experience replacing the rear rubber seal on my '66 230 (w110). It was original and badly cracked. Since I'm doing a soft restore and pretty much a glutton for punishment, I decided to do the job even though many have suggested this is a job best left to the professionals. Actually, I did stop at my local glass shop and the guy took one look at it and said “no way”.

I will say straight-out, that this was the most frustrating job I've done on a Mercedes. This is a long post but I hope I can save someone some grief. I try to arm myself ahead of time by reading old posts, checking the Ponton site for a DIY, and reading the FSM. The cautions were mostly to work when it's warm, don't bend the trim, and use the OEM seal. You will see that I ignored two of them and paid the price in sweat, time, money and beer.

Here it is:
1) Cut-out the rubber holding the garnish molding and remove the molding. The rubber lip cut-out easily, but the garnish molding was very difficult to get off without bending. It took a surprising amount of force plus all the berries came out of their retainers inside the garnish trim rather than popping from the body. Two broke. All were distored pretty badly. They didn't come out of their sockets in the body easily, either. A flat bar with a rag cushion worked best. I was able to re-stress most of the berries so they fit the retainers, but I had to adapt a couple from my 123 parts car.

2) Remove the glass. I cut-out more of the rubber and gently pried out the chrome trim. THIS WAS A MISTAKE. TAKE THE WINDOW OUT WHOLE AND REMOVE THE TRIM ON THE BENCH. I then pushed from the inside as I worked the rubber off the lip and the window came out fairly easy. So far, so good (I thought).

3) Install the new seal. I had a new Febi (at least it wasn't a URO) seal that I bought from a popular website. I noticed it had a permanent scar where someone had clamped it and that it was made in Thailand. Not happy about that, but I was rolling and wasn't going to stop. It took some patience to get the glass into the seal and positioned correctly. The seal wants to pop out behind you when you are working along.

4) Insert the pull ropes. I used small nylon ropes (takes about 22 feet) and pushed it along with a small drift punch. Two pieces overlapped in the middle per the FSM. Then taped the ends to the glass.

5) Insert the molding. This is where things started to go bad. The molding would not go in and stay in. It was obviously distorted. I did my best to bend it back into shape and sort of got it to stay in the rubber on the bench. Let me just say at this juncture: YOU WILL BE SORRY IF YOU BEND THIS TRIM. It bends if you look at it sideways! Very subtle bends cause very big movements. Plus it is a compound bend (with a twist) and once the original bend is lost you will spend an inordinant amount of time trying to get it right. You also have to be sure that the ends meet close enough at the middle so the the little cover catches both pieces. I measured and marked the middle of the rubber for reference.

6) Insert the glass after rubbing a little vaseline on the body lip. Make sure the glass is centered on the body. Using a helper to apply pressure from the outside, I began pulling rope at the bottom a foot at a time, then at the top the same. Well, it wasn't long until the trim popped out. Back out and back to the bench to re-insert the trim. As the trim popped-out, it bent. Re-bend and re-insert the ropes.

7) Try again. Same results.

8) Try again. Do the bottom first, then the top. Same results.

9) Try again. Do the top first, then the bottom. Same results. What is happening is that the rubber on the top rolls and pops the trim out. Every time the trim pops out, it bends.

10) Take the rubber off on the bench and try bending the trim to match the contours of the glass, not the rubber..

11) Try again. Same results. Out of frustration, try pounding trim in place with some soft wood and a rubber hammer. This stupidity made irretrievable wavy distortions in the trim where I pounded. DO NOT DO THIS.

12) Back to the bench. Now I'm thinking to just eliminate the trim. I've seen cars on ebay where someone evidently had the same problem and did this. Upon further thought (another beer), it felt too half-assed and disrespectful to the German car gods. So I removed the rubber again and even more carefully bent the trim to fit the glass.

13) Try again, this time I put a wide poly strap across the top to hold the trim in. Genius, right? Same results.

14) Back to the bench. This time I thought if the trim had a little more bite, it would stay in. So I took a pair of wire cutters and put a little tooth in the trim every inch so it would grip the channel better.

15) Try again with strap. Same results.

16) OK. The factory used some unbelievably hard sealing compound in the body channel and I figured on leaving it because the same voids would still be there with a new seal and frankly it didn't look like it made the installation any more or less water tight. But maybe it was keeping the new seal from completely seating. So I spent three hours with an 1/4 inch chisel painstakingly gouging it out being careful not to scratch the paint. It was a mess and you have to be careful not to ruin the headliner that folds around the body lip and lies in the channel.

17) Try again. Same results. The classic definition of insanity.

18) Sat down. Had a beer. Or two. I began to suspect that the seal was just not right. It seems like the grooves for the glass are not deep enough in the rubber causing it to roll and pop the trim. Made the decision to trash the Febi and order OEM from the Classic Center. With my MBCA discount and shipping it came to about $115. The Febi cost around $50.

19) The new rubber seemed a little long along the top of the glass, but I was able to gather it so that it fit. The trim seemed to stay in better on the bench. Maybe I was just an expert at bending by now.

20) Try again. It went in on the first try.

Lessons learned:
1) Use the OEM seal. Use the OEM seal. Repeat after me.
2) Be very, very careful manipulating the trim. Do not cut it out—take the entire window with seal out and remove the trim on the bench. Use the contour of the glass to be sure it is right before you insert it into the new rubber on the bench. Once the glass is on the car, you cannot get it to seat.
3) Remove the old compound. It is a huge pain to get off but probably necessary.
4) Be careful you don't lose the middle trim cover and the two at the ends. I lost the middle one but was fortunate that one off my 123 parts car fit.
5) Consider ordering new garnish trim berries as the old ones will get damaged in varying degrees.

P.S. I replaced the sunburnt section of headliner with material from World Upholstery. It was an exact match although a little lighter due to darkening of original due to age.