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1987 Mercedes-Benz 560 SL
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Discussion Starter · #1 ·
The wiper linkage on my '87 560SL has about 2-3" of "sweep looseness" at the blades. The consensus diagnosis is that the football-shaped pivot between the wiper motor linkage and the wiper arm driveshaft linkage has one or both of its mounting bolts loose, perhaps one of them missing altogether.

Recently this issue was addressed at JustAnswer.com , where the contributing mechanic, "MB Paul" (Qualified Mercedes Benz Diagnostic Technician - 20+ years experience - Workshop Foreman for Mercedes), suggested the following fix: "It's nearly impossible to get to the nuts to tighten them. I drill an access hole from outside underneath the fresh air grille in order to tighten them and then install a nice rubber body plug with sealant to seal the opening."

Has anyone remedied this issue without this extremely invasive procedure? The hapless OP, whose wipers had stopped moving altogether, cut a hole in his firewall only to discover the pivot to be broken in half, an issue that requires the replacement of the wiper transmission mechanism altogether, and removal of the dash to get to it.

While my SL's symptoms are still just looseness, what techniques, tools, and procedures work best to heal this condition?

(Photo credit: JustAnswers The window wipers on my 1988 560SL do not work. ... - JustAnswer )

Good road,
 

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Premium Member
1975 450SL
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2,441 Posts
When I had to do this, I just tightened up the bolts. The nuts seemed to be firmly attached to the body metal, so anything like the above mentioned procedure was unnecessary.

I just pulled the instrument cluster and was able to get to them with a 1/4" drive handle, extension, and socket. Maybe if the bolts have been loose for quite a while, the nuts could have been broken loose, and that could be where the messiness with the drilling was necessary.

I would try the "simple" fix first. And just for "insurance purposes", a little Loc-Tite might be in order.

Scott
 

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R/C107 Moderator
1986 560SL: '84 500SL: '84 280SL 5 speed: other 107s ALL SOLD
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32,777 Posts
I checked the CD and the paper manuals and could not find anything on this. The section on testing and repairing the wiper motor stated "1. Remove wiper motor" How helful is that?
 

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560SL,380SL,E350
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4,344 Posts
I bought new bolts, grade 8 hex head, and locktited the heck out of them. And that so far seems to have conclusively solved the problem. I had been very close to disaster, with one missing and one very close to coming loose bolt. The slop in the blades allowed them to contact my window brightwork, scratching it.

BTW, I have the shop manual and I don't remember seeing anything about the mechanism itself. Perhaps it never actually was expected to fail, and, other than these bolts coming loose, maybe it doesn't.

I WOULD say, don't go "nuts" torquing these bolts because you COULD break loose the (welded nuts?) on the other side, and then, this would be hell. I have this situation with a bumper bolt. Use reasonable torque and liberal amounts of locktite.
 

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1987 Mercedes-Benz 560 SL
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973 Posts
Discussion Starter · #5 ·
Invaluable advice from you all, I appreciate it.

strife2, "hell" aptly describes what I'm trying to avoid, either from continuing to neglect this repair or botching it badly.

So early next year I plan on going forward with removing the air bag, steering wheel, and instrument cluster. I'll examine the pivot to confirm loose bolt(s) are the issue. I'll then remove one mounting bolt at a time, and check the threads (replacing it if necessary). I'll apply red Loctite, reinstall (or replace) the bolt, then repeat the process for the second bolt. I'll then judiciously torque both bolts, to hopefully--permanently-- restore the original taughtness to the linkage.

I definitely want to avoid this scenario--removing the dash to access and replace the $700(!) wiper transmission and/or trying to find and fix those hidden, threaded fasteners the pivot bearing assembly mounts to.

Hell, indeed!

(Photo credit--another R107 forum enthusiast whom I can't recall. Whoever you are, thanks for sharing this pic of your SL dash removal. You are a far bolder and talented mechanic than I, sir!)

Good road,
 

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Premium Member
1986 560SL with M120 V12 Engine, 1988 560SL Stock
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13,957 Posts
The wiper linkage on my '87 560SL has about 2-3" of "sweep looseness" at the blades. The consensus diagnosis is that the football-shaped pivot between the wiper motor linkage and the wiper arm driveshaft linkage has one or both of its mounting bolts loose, perhaps one of them missing altogether.

Recently this issue was addressed at JustAnswer.com , where the contributing mechanic, "MB Paul" (Qualified Mercedes Benz Diagnostic Technician - 20+ years experience - Workshop Foreman for Mercedes), suggested the following fix: "It's nearly impossible to get to the nuts to tighten them. I drill an access hole from outside underneath the fresh air grille in order to tighten them and then install a nice rubber body plug with sealant to seal the opening."

Has anyone remedied this issue without this extremely invasive procedure? The hapless OP, whose wipers had stopped moving altogether, cut a hole in his firewall only to discover the pivot to be broken in half, an issue that requires the replacement of the wiper transmission mechanism altogether, and removal of the dash to get to it.

While my SL's symptoms are still just looseness, what techniques, tools, and procedures work best to heal this condition?

(Photo credit: JustAnswers The window wipers on my 1988 560SL do not work. ... - JustAnswer )

Good road,
Yes

Mine is also broken in half. Just position the two pieces together and put locktight on the screws and tighten in place. I did that as a patch until I could get a good deal on E-bay for a used wiper transmission. Since it took me about 6 months to finally find a used transmission and it worked so good any way, I never changed the transmission. My guess is I might find it loose again someday and I will just tighten it up.
 

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Premium Member
1986 560SL with M120 V12 Engine, 1988 560SL Stock
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13,957 Posts
Invaluable advice from you all, I appreciate it.

strife2, "hell" aptly describes what I'm trying to avoid, either from continuing to neglect this repair or botching it badly.

So early next year I plan on going forward with removing the air bag, steering wheel, and instrument cluster. I'll examine the pivot to confirm loose bolt(s) are the issue. I'll then remove one mounting bolt at a time, and check the threads (replacing it if necessary). I'll apply red Loctite, reinstall (or replace) the bolt, then repeat the process for the second bolt. I'll then judiciously torque both bolts, to hopefully--permanently-- restore the original taughtness to the linkage.

I definitely want to avoid this scenario--removing the dash to access and replace the $700(!) wiper transmission and/or trying to find and fix those hidden, threaded fasteners the pivot bearing assembly mounts to.

Hell, indeed!

(Photo credit--another R107 forum enthusiast whom I can't recall. Whoever you are, thanks for sharing this pic of your SL dash removal. You are a far bolder and talented mechanic than I, sir!)

Good road,
Hello

I am the other forum enthusiast that you cant recall. and your welcome. Now don't I wish that I had checked and tightened all four of those bolts when I had that dash off. Yeeeees:crybaby2:
 

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1987 Mercedes-Benz 560 SL
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Discussion Starter · #8 ·
Now don't I wish that I had checked and tightened all four of those bolts when I had that dash off. Yeeeees:crybaby2:

Hi Roncallo,

Thanks for sharing not only the photo but the reassurance that all is not lost if I find the pivot broken as well. "Daunting" doesn't begin to describe the thought of me removing a 22-year old SL dashboard with these mitts, let alone getting it all back together again!

One question--four bolts? I thought the pivot bearing assembly has just two, one north, one south.

Good road,
 

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Premium Member
1986 560SL with M120 V12 Engine, 1988 560SL Stock
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13,957 Posts
Hi Roncallo,

Thanks for sharing not only the photo but the reassurance that all is not lost if I find the pivot broken as well. "Daunting" doesn't begin to describe the thought of me removing a 22-year old SL dashboard with these mitts, let alone getting it all back together again!

One question--four bolts? I thought the pivot bearing assembly has just two, one north, one south.

Good road,
Yes there are two bolts on the left pivot bearing and 2 on the center pivot bearing. All you can do without removing the dash is tighten the 2 and maybe a third and then pray the rosary for the other two.
 

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1988 560 SL (sold)/1995 E320
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676 Posts
Hi Roncallo,

Thanks for sharing not only the photo but the reassurance that all is not lost if I find the pivot broken as well. "Daunting" doesn't begin to describe the thought of me removing a 22-year old SL dashboard with these mitts, let alone getting it all back together again!

One question--four bolts? I thought the pivot bearing assembly has just two, one north, one south.

Good road,
GlueckAuf,

Noticed you are close by. When not DIY, who do you use locally for an indie?

thanks,

Patrick
 

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1987 Mercedes-Benz 560 SL
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973 Posts
Discussion Starter · #11 ·
Hi Patrick,

An employment opportunity brought me to Detroit from Dallas (no, seriously!), and as I've only lived in this area for about a year and a half, and haven't needed anything done to the SL I couldn't do myself. Sorry, I can't help you there, bud. I use the MB dealer in Rochester Hills for any parts I can't get cheaper online, but only because it's closer than yours in Bloomfield Hills. If you know of any local shops you recommend, or recommend against, please let me know.

Good road,
 

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1988 560 SL (sold)/1995 E320
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676 Posts
Hi Patrick,

An employment opportunity brought me to Detroit from Dallas (no, seriously!), and as I've only lived in this area for about a year and a half, and haven't needed anything done to the SL I couldn't do myself. Sorry, I can't help you there, bud. I use the MB dealer in Rochester Hills for any parts I can't get cheaper online, but only because it's closer than yours in Bloomfield Hills. If you know of any local shops you recommend, or recommend against, please let me know.

Good road,
Wow, from Dallas to Metro Detroit... Enjoying the weather? :D
Our area gets a bad rap but there are still some great places to go.

as far as indies, when needed, I use Motorwerks in commerce township (15 mile & Haggerty) and sometimes karl Heinz in Royal oak, but he always scares me when describing work they are doing or what is needed on customers cars. He tends to imbelish the gravity...:rolleyes:

I use to bring my cars to Eurotech (they moved to Stephenson hwy) but it's a one mechanic operation which is not practical depending on the scheduling.
 

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1986 560 sl, 1979 300 td
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4 Posts
I'm screwed

Wipers on my 560 got sloppy and then quit. Could still hear wiper motor so I knew that was not the problem. At dealer (they have not robbed me yet), they brought me into the shop and showed me plain as day that the football shaped piece had sheared in two; the bolt and half of it visible in the first pic posted were just gone. The parts manager came in and said that single piece was not a part' i.e. you had to buy the whole assembly. I knew then that I was in for a MAJOR expense because even I could see that the whole assembly could not be installed without removing the dash.:eek:

The good news was that the parts guy found a used assembly for $200 as oppossed to $839 for a new one. Still looking at a major labor bill I thought.

Friday afternoon (2-12) the service writer called and told me that the mechanic thought that he may be able to install it without removing the dash. I didn't see how that was possible until I thought that maybe he was going to take it apart and just replace the broken "football" shaped piece and bolts. Does anyone think that this is possible?

Waiting to hear from them, hoping for the best
 

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1987 Mercedes-Benz 560 SL
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973 Posts
Discussion Starter · #15 ·
Thanks for the information on your similar problem. Be sure and let us know if and how well your dealer accomplished the repair without first removing the dash. If he pulls that job off cleanly, I believe I'd buy the tech the beverage of his choice!:beerchugr:

Good road,
 

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Outstanding Contributor , Bob's Your Uncle!
83 280 SL- 5 speed-The PIG
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34,721 Posts
I think I'll take a look see myself before I re-install the gauge cluster in the Nobmobile.
 

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1987 Mercedes-Benz 560 SL
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973 Posts
Discussion Starter · #19 ·
Wiper Linkage Pivot Surgery--Done

With the temperature in Michigan nearly 50 degrees F today, conditions were ideal for (unheated) garage work, so I decided to explore and hopefully remedy the cause of the 2" to 3" slack at the blades of my '87 560 SL's wipers.

Using the sage advice here, I disconnected the battery, removed the airbag, the steering wheel, and the instrument cluster. What I found was all-too-common among SL owners.

One of the two bolts that hold down the that football-shaped, cast aluminum pivot between the wiper motor and the rest of the wiper transmission was missing (Photo 1). The other bolt was still in place, but a turn or two loose (Photo 2), which was allowing the pivot to rotate to-and-fro rather than transmit the full motion to the wiper shafts, and imparting all that looseness at the blades. Eventually, I was thankfully warned by several of you, the looseness can become so acute that it damages the windshield's bright trim or the paint just beyond it, or snaps the pivot altogether, necessitating a staggeringly expensive and difficult repair. Fortunately this pivot was not (yet) bent or broken, so my repair would be limited to simply replacing the bolts.

I replaced the missing bolt with an M6 x 20mm, grade 8.8 bolt, giving it a couple drops of blue Loctite before insertion. I started it in by hand until finger tight, then gave it a reasonable amount of torque to snug it down.

I then removed the driver foot well pedal cover and the one large plastic ventilation duct behind the knee bar to get at the far bolt from below. Once I snaked my arm to it past the jungle of brackets, vent hoses, and wiring, it unscrewed easily by hand. I had been only perhaps a few Michigan rainstorms away from a catastrophic failure.

I replaced the second bolt with a new one as well, adding blue Loctite as with the first, and snugged it down with a short 10mm open end wrench and alternately, a 10mm socket on a 3/8" ratchet. (These bolts are not easy to work with, as the crowded under-dash limits available movement. And the angle of the bolts makes it tough to get good purchase on them. But patience and a variety of tools helps.)

Once both new bolts were secured (Photo 3), I checked the free play at the wiper blades and found it had been reduced from a good 3" at the far tips of the blades to virtually zero.

In keeping with the "107 Owner's Motto", I plan on refurbishing the instrument cluster (a la Nobby's great tutorial) before I put it all back together, and perhaps replacing the steering wheel slip ring which has always uttered an annoying "meow" with every left turn. (Gotta check the price first to see if it's cost effective.)

I appreciate so much the great advice and invaluable experience brought to this forum by you all--and especially with this job, Radio Tek, roncallo, and strife2. :thumbsup:

Good road,
 

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