Bosch Aerotwin or equivalent aero wipers on E31?

**tangcla** · 01-01-2019, 08:08 AM

I know we've got the reverse J hook, has anyone found a set of aero wipers which can be used on the E31 without any modification to the wiper arm?

**e31gixxxer** · 01-03-2019, 09:31 AM

Only by reversing the hooks.

http://www.bimmerforums.com/forum/sh...ght=Aero+wiper

Now running Bosch retro fit aero blades. 22” O/S, 20” N/S. I will explain the reasons shortly, but first some maintenance.

While the arms were off I removed the plastic trim covers and pollen filters.
On top of the wiper spindles is a circlip and washer. Removed these and undid the nut that secures the spindle bush.
By working the spindles back and forth, with plenty of WD it is possible to get the spindles out enough to allow them to be greased properly, without completely removing the linkages.
Lubricated with grease instead of rusty water, nice!
There is an O ring that sits below the washer on the N/S spindle. This was non existent on mine and there was signs of water ingress on the blower motor that is underneath.
I cleaned this up and fitted a new O ring.
Also greased the other accessible moving parts of the linkages while in there.
Reassembled and on with the modified arms.

I know the blade sizes sound ridiculously small, but due to the arcing and overlapping action of the arms, there is virtually no less screen cleared.

The N/S OEM wiper blade has an offset mounting, whereby the mount is about 1 ½” nearer the N/S than the O/S.
All the aero blades I have found have been central mount.
This means that if you fit a 24” blade it sticks out 1 ½” too far on the N/S. I did shorten one, but too much messing around.
I found that a 20” blade is slightly shorter on this N/S area by about ½”, which makes a nice snug fit behind the bonnet. So ½” less screen cleared on the top of the ark up the N/S “A” pillar to the top of the screen.

The 3 ½” that is missing from the other end of the blade leaves a small triangle 3” wide at the base and 3” high to it’s point at the base of the screen, central to the N/S bonnet vent. Most of this is below the line of view from inside.

The O/S wiper still clears the screen to the blacked out edging at the top. Why does it need to clean the window rubber? If you have the sun visors down these are lots lower than the reduced area of uncleared screen.
The Bottom of the O/S screen has about 1” more of the uncleared semi circle visible. This is the area behind the clock pod and doe’s not obstruct my vision.

There is quite a lot of load on the linkages so I am quite happy to stick with this setup and see how it goes.

The overall length of the blades are reduced by 12.5%, therefore 12.5% less friction acting on the system.
The overall weight of the wipers is reduced by 47%, therefore 47% less weight acting on the system.

That’s got to be good.