Shmurzik

Hi,

My windshield wipers are dragging ***. Unless there is a pool of water to clean off, they are sort of moving in increments, like a seconds hand on a watch. The wipers are new, I think, Bosch (with those plastic spoiler thingies), purchased from Devek at the end of summer. The windshield has been Rain-Xed, which helps.

Still, I would like to know what I've done wrong. 'Cause this is annoying

Robert_H

This may sound strange, but how long ago have you used the Rain-X ?

For me, I have found that using Rain-X is like being addicted to a drug. If I don't keep using it, the wipers start to drag and skip on the windshield. So I end up using it every other week during the rainy season.

I also use that anti-fog "pink" stuff that they sell at the Auto Show every November for the glass inside my car. Every other week also...

It's an addiction I tell you. It's a PITA, but it works and we still drive our cars !

Rob

Shmurzik

Well, I started using it because the wipers were dragging... So, that probably is not it

Jessa

Try some serious glass cleaner on the windshield - not that panzy Windex stuff. Bosch blades and clean glass give great result on my sharks without the use of rain-x.

Failing that, maybe there's an adjustment somwhere to get the wiper arms pressed more firmly against the glass?

Ron_H

Someone posted that rain-x, once applied, would cause more woes down the road. I think he is right, because my wipers will bounce and drag unless there is a lot of water present on the glass. After all this rain goes away, I will try lacquer thinner on my Rabbit glass to remove the rain-x and that should improve performance. I too have found that new Bosch wiper blades are excellent, until they encounter a rain-xed windshield. Since I am having my 928 windshield replaced in a week, I will report how much better or worse performance is on virgin glass. Stay tuned to this station.

I think rain-x is great for situations wherein your wipers have failed and you're stuck in a downpour. I've been travelling across several states when I lost my wipers and rain-x saved the trip. But I needed to be traveling above 60 mph for it to be effective. Otherwise, leave it off the glass. If anyone knows something more effective at removing it than lacquer thinner, please tell me. Thanks.

Garth S

Does sound like there's not adequate horsepower at the blades, rather than high friction blades/'goo' on the glass, etc.
Either the wiper motor isn't producing (bearings/brushes) or there are high friction losses in that fantastic arrangment of drive rods/joints/bushings under the cowl.
Remove the plastic cowl cover over the wiper moter: pop off the drive rod from the ball stud and move the wipers by hand and then turn on the wiper motor(and listen) - this may indicate the problem. Hopefully, the motor is OK.
The easiest ( and most likely) cure is to lube each joint of the drive mechanism - plus, remove the wiper arms and run a little oil into the bushings of the knurled shaft. 'Ya never know - but it may work.

tuk_928

Garth S, I believe you are onto something here. In my older 5-series BMWs (1972 e3 Bavaria & 87 e28 535is) I have suffered a similar problems with respect to wiper function (i.e., slow moving and/or chattering wiper blades) no matter how clean my windshield might be. This is a problem common to the e28 and e12 5-series BMW most notably and much has been written about it on the various forums and in the chassis FAQs. I'm not sure if our friends at BMW solved the issue with the e34 5-series (like your 1990), however. I suspect the 928 wiper transmission is somewhat similar to that found in the BMWs of the same era in terms of the Bosch wiper motor, rods, joints, bushings, etc. The "FIX", according to the FAQs, centers on refreshing the various components in the wiper transmission. Otherwise, lubrication of the joints with white lithium grease (I believe???) was the quick (but not long-term) solution. Let me know if you're interested in the details and I'll see if I can dig out the details of the fix from the 5-series FAQs.

Best regards,
TUK

Dennis Wilson

Acetone or acetone based fingernail polish remover should remove the rainX. BTW don't get it on your paint.

Dennis

T_MaX

This helped mine a little.

Hidden Ground

Also it maybe time to lube all the windshield wiper mech. bushings (sugested first by TUK)?

G Man

I encountered a problem on my 81' when I first got it. The driver side wiper worked good put the pass side would hardly move. Truns out that the nut that holds the wiper arm to the splined, tapered shaft was in need of a tightening. Gave it about a half turn and it works as it should.

Niels Jørgensen

FWIW: Mine is the same, regardless of the quality and age of the blades.

And now that we're at it: why the F* do they equip a very expensive high-end sports car with a flimsy, semi-functional, noisier-than-hell wiper that is completely useless above 80mph and is about 10cm too short, leaving a very large area of the windshield on the left unreachable and thus constantly filthy?

I don't get it. Didn't they ever drive the damn thing in the rain?

This is IMHO the only major flaw of the 928. A friend of mine has an 88 Merc - a very ordinary 2-something, same year as my 928 and available for just a fraction of the price, yet it has the most awesome single-wiper system that is both silent, effective and cleans the ENTIRE windshield in a second, wet or not.

It's quite pathetic, really.

Garth S

I had reasonable success with the wipers on the '80 several years ago by lubing them as described in my post above - used mobil1 syn sparingly, and a 'bamboo skewer' to reach into the difficult areas - they're still working well.
T_max, a good tip re. the ground connection.
TUK, thanx - would be interrested in the BMW ref. Knocking on wood, they're still as new.
Niels, you're correct on all counts! The Benz single arm system works great - my first experience with it was at speed in rain/snow in Switzerland - zipping down the autoroute looking for the correct "Ausfart".
The jerky broomhandle movement takes some getting used to - but it preforms like no other.

sweanders

I've also been a bit annoyed by the fact that the wiper speed isn't speed related. Even on the 1988 Volvo 480 that was my firt car the wipers went down to interval mode when the car was slowed down to standstill.

Niels Jørgensen

Yup, and who the heck placed the speed adjustment **** under the pod? What were they thinking? The whole washer/wiper thing seems an afterthought.

"Ach du lieber hansi, waz if zomeone zakes this thing out in ze rain?"

"Sheisse Fritz! Quick, get ze wiper from my 1951 volkswagon - zey will never notiz"

Kevin in Atlanta

Had the same issue. I went to the GTS blades with no help. Finally, I replaced the wiperarms. Completely eliminiated the chattering and windows are streak free.