Windshield Wiper Installation Question

[AyRoMoDa]

I have MkIII Roadster S/N 6911 and am having a problem with the windshield wiper installation. I installed the wiper motor, tubing and mechanisms according to the instructions provided. The assembly is wired up and works fine until the wiper blades are installed. If I install the blades and have them tilted back on the spring without touching the windshield they work fine. As soon as the blades are placed on the windshiled, the passenger side wiper does one sweep fine but the next sweep indexs down into the engine compartment, jams and it sounds like the gears are skipping. The drivers side just skips and doesn't even attempt to sweep. It appears that the splines in the wiper arms are a lot smaller than those on the wheelbox spindles. The only other thing that I can see that is suspect is that the nozzles coming through the hood are 1 - 2° off from the template. I can't get them to sit flush against the retaining nut and the body because the wheel boxes are jammed against the firewall (fire wall forward kit installed) preventing that little extra angle. Is this enough to cause the problem I'm having? I'm at a loss and anything you can suggest would be helpful. Thanks.

Paul

[edwardb]

Welcome to the world of the vintage Lucas wipers! Probably FFR will answer, but couple of observations and questions based on my experience installing these wipers on my Mk3 last year.

1 - 2 degrees one way or the other shouldn't make a big difference. What you need to do is replace the supplied rubber tube spacer with something that holds the angle of the wheelbox against the body better. Most guys use either PVC or aluminum. I used a piece of square aluminum tube, 3/4 inch as I recall. Whatever material you use, experiment with the length and angle to get the outside retainer to meet exactly to the body and expose the same amount of threads on each side. Mine were actually slightly different in length because the body was a little thicker in one wiper location compared to the other. With a proper (and solid) spacer underneath, you will get a much more solid mount and properly set angle. I don't have any experience with the firewall forward modification, but I know lots of guys have done this mod also with wipers, so it should work.

Regarding the wipers slipping/grinding. Can you confirm exactly where it's slipping? I'm assuming not the cable at the motor. This is a pretty robust connection, so doubt anything is happening there. Is it the cable in the gear boxes, or the actual wiper not locking onto the stub through the cowl? My guess is probably the wheelboxes themselves. Many guys struggle to get this working well, so you're not alone if that's the problem. Lots of threads on this exact subject in the "other" forum, describing how to bend the cable retainers on the wheelbox to get the cable to mesh better with the gears. Some gear boxes, including the ones that came with my kit, had the gears cut down on about half the circle. You had to make sure the gear was properly indexed to the cable, or it wouldn't engage properly. I actually changed to an aftermarket wheelbox from ********** that is from a different supplier apparently. It's slightly different construction and meshes perfectly without any adjustment.

[AyRoMoDa]

edwardb

Thanks for the reply. I think it is slipping in the wheelboxes. I'll try your suggestion of a PVC tube spacer. I also checke the 'other forum' and have some ideas to tighten the wheelbox/cable connection. If that doesn't work, I may have to go the ********** route. Even though I am just in gel coat, it is really frustrating because this is the last thing I need to get working before going to the DMV. That can be a 4 - 6 week process here in NY and I am afraid that I may not be on the road before the snow starts to fly.

Thanks for the advice,

Paul

[Jason Lavigne]

Hi Paul,

Good advice from Edwardb - I might add that sometimes the teeth on the wheelbox gear seem to be cut deeper into one portion than the other, around the circumference of the gear. That might be a good thing to check, and if you can, index the wheelbox shaft so that you're using the best part of the gear.

Have a nice weekend!

Jason @ FFR

[Cobradavid]

Paul,

I had trouble with one of the wheelboxes also. It worked fine with no load, but when it was under load (the wiper blade sweeping across the windshield), the cable would slip some teeth and the arm would end up misaligned just like you described. I lubricated the cable and wheelboxes but that wasn't enough. I realized that the wheelbox wasn't holding the cable close enough to the gear to fully engage the teeth. It was as if a spacer or tensioner was needed to push the cable closer to the gear. I had to do some re-working on the wheelbox to adjust it so it held the cable closer to the gear. Now it works fine.

David