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Single Wiper conversion - How to 9 years 8 months ago #140122

Ever since I saw Allan's single wiper on his MG TF I've wanted one on my LE500. I really don't know why except that it seemed such an elegant solution. It can be implemented with mimimal change to the existing scuttle holes. In fact all you have to do is blank up the driver side hole with the readily available plug. So for me the attraction has been mainly aesthetic.

Allan points out that the twin wiper linkage is also a weakness and this is supported by Mike Satur who sells an upgrade to the existing linkage. Many others have had to make up quick fixes when the linkage fails.

The problem with going down this route is that single wiper conversions for the MGF and TF are not available. Storm used to produce a conversion and it is this kit that Allan and Rob have used for their cars. However Storm no longer produce any kits and old stock is not available. In fact stock of any models are becoming rare. Despite a number of attempts to engage the original proprietor of Storm we have manifestly failed to source a kit for the MGF/TF.

Faced with this obstacle I was forced to investigate other options.

It seemed to me that the one unique feature of a single wiper mechanism should be common across all Storm kits and if I could obtain a kit for a different model I might be able to modify it to fit.

What then is the difference between a twin wiper and single wiper mechanism?

Well, a twin wiper mechanism looks like this, with one lever:

whereas a single wiper mechanism has two:

This allows the wiper spindle to move through more than ~90 degrees.

Here is the Storm conversion for the MGF/TF

So this is the kit we are trying to re-create.

I reasoned that all conversions would have the same critical linkage. The only variables would be the length of the long arms and the spindle length and diameter so if I obtained one with a longer arm than needed I could cut it down. I was also certain that the arm for a different model would need to be re-bent. The spindle could be smaller in diameter in which case I could sleeve it. I didn't consider that it could be greater..which it wasn't, fortunately! If the spindle was longer I could space it out from the arm. So I was looking for a new or used conversion with a longer arm, a spindle which is the same or smaller diameter and the same or greater length than the proper MGF/TF conversion.

I searched eBay for used linkages and bought an Astra mk4 single wiper conversion. Cost me £30 delivered..Bargain!
Vauxhall astra mk4 single wiper conversion

So what do we have?

How do we get from this to one that will fit on the MGF/TF?

Issues are:

1. The spindle has a threaded sleeve thingy over it.
2. The spindle is longer than the existing one.
3. The spindle is smaller in diameter (10mm) than the existing one (12mm)
4. The long arm is too long and bent in the wrong direction.

So what we do is this:

1. Remove the circlips securing the threaded sleeve and discard it. We also don't need the circlips.
2. Use a spacer to effectively shorten the spindle. This is also gains more clearance for the lever mechanism
3. Increase the spindle diameter using a mild steel tube.
4. Drill out the rivets securing the wiper motor arm to the long arm
5. Cut and re-bend the arm
6. Reassemble with machine screws and nylocs

Focusing first on the spindle mods this is what we need:

See one of the existing wiper spindles for comparison
In addition to the bits off the existing mechanism we need a 60mm tube with OD of 12mm and 1mm wall. We also need 3 mild steel washers and this is how we assemble them..

Add the spacer (3 washers) and the small thrust washer.

Add the tube..

Lube the tube with grease and insert into the existing arm..

Assemble with small O ring, small washer and circlip, washer and nut.

Attach the wiper motor actuating arm to the wiper motor

This is the finished article..but after bending, cutting and drilling the arm which is relatively trivial in comparison.
However, this is how I approached it.
I installed the small wiper arm onto the wiper and the long arm into the linkage and bent the arm so that it would overlap the fixing holes.
I then cut the arm and wrapped masking tape around it so I could mark the fixing holes.

..and this is the critical bit..
Make sure before you mark the holes that the wiper arm is at 90 degrees to the long arm and the long arm is at mid-position.

Once marked, drill the holes and fix with small machine screws and nylocs.
..and that is it now we have a single wiper conversion for the MGF/TF. I was able to demonstrate it at the All-Mod-Cons inaugural BBQ on Saturday..Seems to work fine.
Here is a vid of it working

Am I going to use it?. No!

Despite it being aesthetically superior to the standard twin wipers and much more robust I really cannot resolve my issue with it not optimally sweeping the screen.

I believe Allan and Rob overcome this small deficiency by using Wipex to keep the screen clear
But for me the aesthetics cannot overide functionality

I've also investigated the new Yaris single wiper mechanism which might work but there would be an issue with the percentage of screen swept. It would provide better visibility to the driver than the standard setup but the passenger wouldn't be able to see out much. As such I suspect it would fail the MOT. It would also need a different placement of the wiper spindle.

It is possible, but unlikely, that the old Mercedes mechanism could be used to provide a single centred wiper but one which sweeps most of the screen. Unlikely because the mechanism is substantial and a lot of it would be outside of the scuttle panel.

So for now I'm going to buy the MS upgraded wiper linkage and think more about it.

At the moment Chris has first dibs on the conversion.

If any of this is unclear or you would like more photos let me know..I have a few!
"You can’t be a real country unless you have a beer and an airline – it helps if you have some kind of football team, or some nuclear weapons but at the very least you need a beer"
- Frank Zappa
The following user(s) said Thank You: David Aiketgate, Leigh Ping, cairnsys, Davem, pgew

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Single Wiper conversion - How to 9 years 8 months ago #140125

Nice work. :broon:

Why single wiper is not for me.


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Single Wiper conversion - How to 9 years 8 months ago #140158

That's a brilliant investigation. Much appreciated and worthy of a place in the guides section as sage advice to others. :broon:

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