Hi,
after replacing my wipers (original Porsche) they still are'nt performing. They seem to "jitter" at normal speed. When speeding up the wipers (not the car) the problem seems less.
First I thought the rubber was to hard but now I think the pressure of the wipers onto the windshield is too low (or maybe too high?).
Is there a way to change the pressure? Does this make any sense?

Thanks,
Paul

 

I don't think there is a way to adjust the pressure on the glass. I've found that wiper action is improved a lot by thoroughly cleaning the glass, and not just with liquid cleaners. I use a very fine paint polishing compound on the windshield as it removes grim, grit, bug juice, road tars, and makes the glass surface very smooth. That does more for wipers than anything. In combination with new rubber you should notice a big difference.

 

Rain Ex took my chatter away.
Thomas

 

BonAmi cleaner is a good heavy-duty cleaner for glass. Not for routine use.

Chatter can sometimes be reduced by carefully tightening all of the attach points on the wiper blades. That is, bend the little metal tabs that hold the blade links and attach points to reduce the free play.

The only way that I have found to change the blade pressure is to bend the small rectangular part of the arm up or down where it enters the sheet metal part of the arm.

 

You may need to adjust the angle of how the wiper contacts the glass. I have had to use this method on a couple of vehicles to eliminate the chatter. When the blade wipes across the glass the angle of the tip of blade should be such that it is dragging in the direction of travel rather that pushing. I usually use a crescent wrench on the wiper arm to adjust. You definately want to make sure you have fresh blades that are not brittle and dried out also.

 

Happened to have both cars in the same place this AM, and recall somewhere someone mentioned that GTS wiper arms have double springs. So I took some pics. My '90 is single spring, while the GTS is double springed. PET lists the same part # for 87-95, 928 628 213 10. So do you now get a double-spring arm when you order a new one?

1990 Wiper arm:




1993 wiper arm:

 

I,ve been using this new design on my 4x4 recently and they are much better than the old design, ie metal type with bridges.
I,m thinking about fitting some to the 928, and see if they are more stable/ judder free, as I,ve noticed that has gone away with the new design .

http://www.demon-tweeks.co.uk/Perfor...lades/549/3183

Ken
80 928 S
5 Speed

UK

 

Double springs don't necessarily mean double pressure, or even more pressure. Probably a safety precaution.

 

Whilst on the subject of wiper blades, I went to buy some Aero-Flat wipers, and was asked what year 928 are they for, I was a little puzzled as I thought all years were the same, ie, regarding length of blade ?
The guy said 78-84 have 18" blades, and the 84-90 have 19", has anyone any idea why ? got me stumped

Ken
80 928 S
5 Speed

UK

 

If you continue to experience problems consider trying a pair of Bosch Icon wipers.

I got some from Roger awhile ago and they look and work great.

 

This :

I pretreated my windshield

Ammonia (Wind-x) or a washing solution of white vinegar and water. Using black / white newspaper, wash the windshield clean until its streak free.

Treat with rain-x

 

I use Zaino on my windshield. Does as well as rain-x, doesn't get chattery as it wears off and lasts longer.

 

Hmmm... it kinda looks like they may have two springs for a lower profile/better appearance.

My Icons float over 100. Entirely useless over 110. Fortunately my test track is dead straight, with a guard rail down the center, but I can't do 4th gear tests when it's raining.

Do the original wiper arm aerofoils work?