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James.

Wiper linkage

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Getting the VR ready for an MOT and found the linkage baggier than a clowns pocket (bushes on the  lower bar are heavily worn - see image).

Anyone worked/working on a solution ? Or have anything NOS they would move on ?

Screenshot 2022-11-20 at 11.52.11.png

Edited by James.

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By chance yes, I'm currently working on some options for replacing the bushes so hopefully will get something that works. I will report back if successful so maybe watch this space!

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Good show. Just knew there’d someone either crossing or about to cross that bridge.

Yes, keep us updated please.

Anyone have a spare one of the above, feel free to get in touch.

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Good stuff - I'm in the middle of rebuilding mine due to corrosion and still looking for the long link arm - I have the short one from a group buy on here a while back.

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I currently have mine off the car, it looks to be in okay condition. But I did have the thought of what would I do if the joints needed to be replaced. The best route I could think of was creating new rods with spherical bearings at the ends, like rod ends with spherical bearings. What I would say, is don't use cheap spherical bearings.

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Right, this is where I have got to so far:

Initially I tried to see if I could replace the plastic bushes/bearings with off the shelf nylon flanged bushes, with a slightly smaller diameter than the ball joint. The idea being that with a bit of heat and a vice the bush would expand over the ball joint to grip it tightly and also expand into the hole in the link arm to lock into place. Had to cut them down substantially and it sort of worked but I wasn't massively happy with it, and you'd still need to use those metal clips to lock it into place.

So I looked at developing a replacement for the original plastic insert and have modelled it in 3D CAD. I thought about 3D nylon printed initially but have dismissed this due to the rough surface finish, that would also be porous. Not ideal for a bearing surface. I am currently trying to get some quotes for CNC machining the part out of nylon, which should give a reasonable finish. However, the only way this is economical, due to machine set up, is with a group buy. Looking at Nylon due to its wearing and natural lubrication properties. At a push I'd guess the originals are the same.

Further things that need consideration are with actually getting the part installed. Looking at the original I am fairly sure it is stamped/moulded in place onto the link arm. There're some indents on the link arm around the holes, and these can be seen imprinted on the back of the original bushes I have removed. Trying to push a new part in could be difficult, but there's a possibility I could make the flanges a bit smaller to make this easier.

Also the bushes are slightly different at each end. at the motor end the bush has two lugs, which as far as I can see stop it rotating too much on the mount. However, I don't know if these are essential. 

I have also had a quote for a vacuum injection process that uses a silicon mould for small batches of up to about 20. This is obviously much cheaper than full injection moulding. However, it would be in Polyurethane not Nylon and I don't know how this would compare for this application. I know you get Polyurethane bushes for suspension and drive train parts, but as far as I am aware these contain metal bearing surfaces. The cost for this would potentially work out somewhere around £50 a bush if there were 10-20 takers. Although if we were to go with identical bushes at each end this would be more like £50 a pair, which could be a bit more palatable, but still pricey. 

So I think my plan is, get a couple of prototypes 3D printed just to test fit. 

Then, if it all works OK see if the CNC machining quotes come back at all reasonable, and propose a group buy. I think these should be better than the vacuum moulding to be honest, from CNC machine quotes I have had previously.

Anyway, thoughts welcome!

 

 

 

 

 

 

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Had a quote back on the CNC machining and it's a lot better than the vacuum moulding. That should make a group buy more achievable I think, perhaps around the £20 a pair mark.

So what I will do now is get a prototype printed as this isn't too much and see how it fits. Then if all good I will put up a group buy.

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have the same problem with these bushes believe its making my wiper arms move positions during the sweep making it impossible to prevent it clattering my scuttle panel or a pillar, would be interested in a group buy if one comes available. 

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Yes, this is exactly the problem. It makes the system very slack, and whilst it's a small rotation at the spindle, when translated over the length of the wiper arm it's quite a big movement.

I have just about set my wipers up to avoid hitting with the pillar or scuttle, but it still gives over time. I don't think the fixing into the scuttle panel is very good either. It's just a plastic collar in the hole with a thin washer on the other side. There are only 4 small tangs on the actual spindle which don't get much bearing, so there's not a lot to prevent it moving. The drivers side isn't as bad as it's braced by the motor bracket, but the passenger side it's quite flimsy.

Anyway, 3D printed test part is on order so fingers crossed this will work!

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Update on this, the 3D printed parts arrived, and actually they're not bad. They look like this:

y4mo3-gxxbEWGlQjBeRWj3IcTpnaxhpLGOGJtrfI

I had them vibro polished which made the finish a bit smoother, not really sure if they would be appropriate for the final product, but I feel better about it as an option now.

However, the main issue is getting them in the link arm. I had envisaged this being an issue, as above I am fairly sure the originals are moulded onto the link arm, but hoped that a solution may present itself once I had them. However, having given it ago it's a definite no, as there's no way I can see that the flange goes through the hole even with a bit of heat.

So a bit of a redesign is needed. I think the solution is to reduce the size of one flange and turn it into a chamfer that will initially fit in the hole and then hopefully push through. Probably have to be after Christmas now.

But this has given me hope that we could solve this!

 

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On 12/18/2022 at 7:09 PM, oneohtwo said:

Update on this, the 3D printed parts arrived, and actually they're not bad. They look like this:

y4mo3-gxxbEWGlQjBeRWj3IcTpnaxhpLGOGJtrfI

I had them vibro polished which made the finish a bit smoother, not really sure if they would be appropriate for the final product, but I feel better about it as an option now.

However, the main issue is getting them in the link arm. I had envisaged this being an issue, as above I am fairly sure the originals are moulded onto the link arm, but hoped that a solution may present itself once I had them. However, having given it ago it's a definite no, as there's no way I can see that the flange goes through the hole even with a bit of heat.

So a bit of a redesign is needed. I think the solution is to reduce the size of one flange and turn it into a chamfer that will initially fit in the hole and then hopefully push through. Probably have to be after Christmas now.

But this has given me hope that we could solve this!

 

Nice work on this mate,

Could you use a circlip to produce the flange on one side?

Another idea is a two piece, being glue together in place.

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Update on this: Success!

I redesigned the insert with a tab on one side instead of the big flange in the hope it would push through and spring back out, to clip in. That didn't entirely happen, as the tab just compacted in the hole, and then sheared off. However, it did mean the insert is extremely tightly wedged in, so that it is actually secure. I certainly couldn't shift by pushing down on it on a bench, so  I went ahead and installed it, and it worked! Ran perfectly and there's absolutely no play in the system. No more wipers hitting anything!

This is what it looks like:

https://am3pap007files.storage.live.com/y4myI3eneG6JOEv2jfdAiWnmOC0PFmg8jqVFVwHat7GSdjQEaHTKdMKUTZZLOD4zD6hIhx0sQ9dv3dlj_SqDsqQ2DyiW0E8SlDEeHlIStp6lOinzafdWwBIXChX6yRjWBZQBaiz1_F61okD7oSaC0-UpLYRtDPo6zFmLZj_NaEUH-qJOuGfZO5zVzKy4FoMf7Ld?width=1024&height=576&cropmode=none

https://am3pap007files.storage.live.com/y4mfMSETEjD3LF139vV6VP_LANSE3KgMeyO-cQE_6lnVQRfEmSAVkm3dUJfNb4fhc4vR8GPfFS165A4JP2UXMyaRAG_fJCuX7EfRlokNpGxFFHBfx1KEn0UtXHHgFneNBBU_oPErdX-dYj3cTik_WtU8a3qF4J4q8a2P-01o5iz9XF1RaAlp8A0KZgt0P28pzCS?width=1024&height=576&cropmode=none

And installed:

https://am3pap007files.storage.live.com/y4maM1NwFspZgBSkK-6_FPd9biHzz8QbXKCNUSCJFjMEhDcuEkN5ChnPkhXn1QsAQCxpkFyrbwH9ikAmKK1nlDY_hC9iqu0JiT80K8DE--MrcUNxNgH5XG32d9uaL4Od_sQtoHPS5rwt2V6tQT71Vi9MmG9yW6wTkjmcVvdbHkzYitvYtisdvLzpJsfjnSY1N9X?width=1024&height=576&cropmode=none

You can see the tab has compressed, so it is held in by friction. And this is it installed in the linkage:

https://am3pap007files.storage.live.com/y4mfMSETEjD3LF139vV6VP_LANSE3KgMeyO-cQE_6lnVQRfEmSAVkm3dUJfNb4fhc4vR8GPfFS165A4JP2UXMyaRAG_fJCuX7EfRlokNpGxFFHBfx1KEn0UtXHHgFneNBBU_oPErdX-dYj3cTik_WtU8a3qF4J4q8a2P-01o5iz9XF1RaAlp8A0KZgt0P28pzCS?width=1024&height=576&cropmode=none

You can see that even just being held in by friction the insert isn't going to pull out of the link arm as it's acting in the opposite direction. And the ball joint is nicely held by the shape of the insert so that isn't going to pop off either. It's very snug and tight, but does allow rotation and swivel around the ball joint.

I do have some videos of it in action, but unfortunately they haven't uploaded properly. I will post if I can get those uploaded.

So, I think we have a solution! I have, however, only just twigged about JJBRADO's suggestion of a circlip for some reason, so that might offer a bit more security especially if other people wanted some and were nervous about it just being pushed in. 

The 3D printed versions also seem up to the job, so I am not sure whether to continue exploring CNC machining options. The finish isn't amazing, but seems good enough. I am happy to run with these for a while in day to day use just to see how they hold up, in case other people wanted to get a better idea of durability first. They may not be as durable as the originals but I think we just have to consider them a disposable item that we can swap out when they get worn. Either way I am happy to take views on this. Let me know!

EDIT: I can't get the pictures to load for some reason. Normally they just embed straight away. Will try again later.

 

Edited by oneohtwo

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Good job! I would happily buy some to help get your project off the ground. I am sure the facebook guys would as well to get a bit more traction. 

I haven't looked at others VWs but wonder if the bush is the same size as say the mk2 and mk3 as a wider appeal (though i know their wiper mechs aren't obsolete like ours - just thinking it might widen the customer base). 

 

 

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