Home » What The Hell Is This Little Arc-Shaped Thing On Old Land Rover Windshield Wipers?

What The Hell Is This Little Arc-Shaped Thing On Old Land Rover Windshield Wipers?

Whatisthis Wiperthing
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When we had our Autopian One-Year Anniversary Meetup and Group Therapy Session earlier this month, we brought along a few cars that we thought readers might enjoy seeing: the tiny Peel P50, the also tiny but yellower Berkeley SE328, David’s Jeep J10 pickup, and a fantastic 1956 Finnish Fire Service Land Rover Series I. I’d like to talk about one tiny, tiny detail on that Land Rover, because I’ve never really seen anything quite like it, and I want to know what the hell is going on. The detail is a tiny little arch of metal with two tabs, mounted to the base of the windshield wipers. The hell is this thing?

Here’s a close-up picture of the little bit of metal in question:

Vidframe Min Top
Vidframe Min Bottom

Wiperarc!

It’s not something that the Finnish Fire Service decided was absolutely necessary for safe extinguishing of Finnish fires, it shows up on other Land Rover Series I, II, and IIa vehicles, more specifically ones that used separate wiper motors, each one driving an individual wiper. They’re called “Lucas Wiper Motor Park Gates,” or, more commonly, just “Lucas Wiper Motor Parks,” (which sounds like one of the most niche and dangerous theme parks you can visit) and sometimes “External Wiper Arm Guard.”

Parks

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So, what exactly is this thing for? Looking at it, its function seems kind of obvious: it restricts the boundaries of the arc that the wiper arm describes as it moves, back and forth. What’s confusing is that it’s not like the wiper arm would just go spinning in a circle like a propeller without it; there’s gears and a cam/arm assembly inside that wiper motor to convert the spinning motion of the motor to a reciprocating back-and-forth motion, like you’d expect from a wiper motor. You can see one all disassembled here:

The purpose, of course, is implied in the common name: park. These early wiper motors that drove solitary wipers and had their own independent switches right on the motor housing didn’t have a park function that stuck the wipers out of the way when not in use; instead, I guess you’d use the little metal tabs as a way to help you time when to park the wipers?

What confuses me is that even on other vehicles with similar one-motor-per-wiper setup and also lacking a wiper park feature, I’ve never seen anything quite like this. Look at the old Willys Jeep, for example, a very comparable vehicle with a similar wiper motor setup:

Jeep Wiper

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Okay, those are vacuum wipers, not electric, and while I don’t think that matters here, fine, you win, I’ve also got a picture of a Kubelwagen wiper setup, which is pretty much exactly the same, two separate electric motors, one per wiper, but as you can see there’s no park guide little metal rainbow thing going on there.

I can’t think of another vehicle that has this – maybe other vehicles that used the same Lucas FW2 wiper motor? Though it seems that the wiper motor park – part number HNJ747551 – was not always included with the motor assembly, so perhaps it really is unique to Land Rover Series I-IIa vehicles?

Motor

I think I can’t really understand what this thing really does without experiencing it, and I simply haven’t had the opportunity yet. I suspect it just somehow makes wiper parking easier, by providing a little visual target and stop so you have an extra moment to react and turn off the wiper motor when the arm contacts one of the two tabs?

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I don’t know. Any early Land Rover people out there want to explain this to me? I’m baffled. I just don’t see why you’d need this. Does it somehow take stress off the motor shaft if you park the wipers on the tabs properly? I’m guessing at this point.

It’s also possible they just look cool, because they kinda do. Still, if anyone knows what the hell these are actually for, please, tell me!

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Josh Jones
Josh Jones
1 year ago

I’ll be honest here, I only skimmed the article, and I haven’t read any of the comments yet, but my first thought was to keep the arms from breaking the windshield if you accidentally let them drop while changing the blades

Harmon20
Harmon20
1 year ago

It looks to me like the windshields are removable or replaceable flat plate. My guess is that those arcs would prevent the wipers from dropping into the cab/frame when actuated while the windshields were out and possibly breaking something when they get hung.

Last edited 1 year ago by Harmon20
BetterThanAverageJoe
BetterThanAverageJoe
1 year ago

It’s clearly wiper brakes: https://www.youtube.com/watch?v=eMapKS5ax3o

StalePhish
StalePhish
1 year ago

I was going to say, looks like a brake rotor for wiper breaks! Just watched a tutorial video on how to replace the pads just the other day ????

Paul Brogger
Paul Brogger
1 year ago

Didn’t YOU, Mr. Torchinsky, at some point in the recently aftseeable past, write an article begging for a wiper feature whereby the blades could be momentarily lifted to dislodge some annoying pine needle to restore clear vision?
Briefly somehow push that arch away from the car, and voila!

FlavouredMilk
FlavouredMilk
1 year ago
Reply to  Paul Brogger

This was the first thing that came to my mind when I saw this article. What better than a tiny little cam just to give enough clearance to dislodge a leaf or stick.

DolanDuk
DolanDuk
1 year ago

COuld it just be to hold the wiper arm away from the windshield in case you lose a wiper blade? and still want to use the other single wiper? It would stop the end of the wiper arm from scratching the windshield? You’d need to take off one of the wiper blades to see if it keep the arm off the glass.

Data
Data
1 year ago

This is an espresso machine.
No, no wait. It’s a snow cone maker.
Is it a water heater?

Desmosedici
Desmosedici
1 year ago
Reply to  Data

Do you know why you’ve been brought here? So this man can verify to the world the Crimson Jihad is now a nuclear power.

Sid Bridge
Sid Bridge
1 year ago

Man, I had to delve into Land Rover’s shady past, but I’m pretty sure those metal things were for intimidating someone you wanted to squeeze information out of. Simply first one or two of their fingers into that ring, have your accomplice ready to switch the wipers on, and listen to your mark sing all the classified information you were hoping to hear before you flip that switch and make it so he can only count to 8.

Not foolproof, obviously, if your mark knows the electronics are made by Lucas, he may risk the finger.

Last Pants
Last Pants
1 year ago
Reply to  Sid Bridge

And I don’t know if it will work either. The question is do you feel lucky, punk?

Vicente Perez
Vicente Perez
1 year ago

As some have guessed, it is probably to prevent any wiper blade malfunction from damaging the windshield or even the hood.

Our much newer Rover 800 had a somewhat related system. There are mounts at the bottom of the wiper arch. With the wipers off, you can slightly lift the arms so the wipers rest on those mounts and slightly away from the windshield. This could be used, among other things, to prevent the blades from sticking when the car was parked in freezing temperatures.

You can kind of see it here

https://assets.carandclassic.com/uploads/cars/rover/C1527473/1989-rover-800-6385c7d2df097.jpg?ar=16%3A10&auto=&fit=crop&h=560&ixlib=php-4.1.0&q=75&w=900&s=be7909e61e0b8674e424c3b948877394

Last edited 1 year ago by Vicente Perez
MegaVan
MegaVan
1 year ago

It’s hard to tell from your photos, but the shaft doesn’t appear to be keyed.

Given that situation, how would you know/guarantee when installing where “center” was for the motor? By guess would be that it’s an oddly necessary gate so that if you start running with the motor upside down it doesn’t slam them into the car.

Be interesting to see an installation procedure. It could clear things up. “Set the motor to the park position. Set the wiper on the provided stop. Bolt down.” etc.

Miguel Plano
Miguel Plano
1 year ago
Reply to  MegaVan

The shaft is not keyed and the motor does not have a park position, i mean, where you cut power is where it stops.

I explained below, it is for stopping the wiper blade to be out of the bounds of the windshield when you use the hand crank to operate the wiper blade.

Hugh Crawford
Hugh Crawford
1 year ago

So you’re the windshield wiper designer at Land Rover, and your design brief is that you need really powerful windshield wipers, because they need to remove water, dust, mud, and the occasional wild animal, or tree branch from the windshield, which takes a fair amount of power I would imagine. On the other hand if the windshield wiper can’t move, say the wet cement isn’t quite so wet by the time you try to remove it with the windshield wiper or a wildebeest has gotten a hold of it or there’s a baby elephant sleeping on the windshield, you don’t want to break the wiper or the motor, and limiting the torque of the electric motor would mean that it might not have enough omph with a low battery.

So what do you do? Put a clutch in there somewhere, perhaps as simple as slowing the shaft to slip at the wiper or as elaborate as something in the wiper motor.

So fine, there is a safety fuse as it were to keep the wiper from destroying itself or breaking something else. But what happens when it slips and instead of hurling a baby elephant from its nap spot it de-indexes itself? Well that mystery Little Arc-Shaped Thing re-indexes the arm and all is well.

Owners of old floppy drives in the 80s would be familiar with the concept

Miguel Plano
Miguel Plano
1 year ago

Having a Mini Moke with the same wiper motor sans arch, I know exactly hat are they for, and they are brilliant and I need to get me one of those.

These wiper motors have a hand crank, you pull on them and it disengages the gearbox, the unfortunate consequence of doing this is that the wiper blade is free to rotate 360 degrees.

The arch is to stop the wiper blade from going too far in either direction when you are using it manually.

Mike Harrell
Mike Harrell
1 year ago
Reply to  Miguel Plano

Yes, this is the correct answer.

Paul B
Paul B
1 year ago
Reply to  Miguel Plano

Ahh, Lucas reliability strikes again!

Ron888
Ron888
1 year ago
Reply to  Miguel Plano

I’m trying to imagine any sort of hand crack that makes sense.It would have to have a little heft to it,surely?A teensy thing would be ridiculous.
I’m actually hoping the answer is the motor box itself is the handle.Coz that would work on several levels

Miguel Plano
Miguel Plano
1 year ago
Reply to  Ron888

It is a small crank that you operate with two fingers, the crank position is 1:1 with the wiper blade, so you have to move it back and forth yourself.

I sent a video to Jason, but once i explained what it was he stop caring about it. I guess it was not interesting enough.

Winsome Badger
Winsome Badger
1 year ago
Reply to  Miguel Plano

This is the correct answer. I had a series 1 Land Rover with the same thing. The motors were too weak to cope with much mud or snow so there is a lever on the back to give a helping hand.

Miguel Plano
Miguel Plano
1 year ago
Reply to  Winsome Badger

Thank you and yes, they are. I think mine cleans anything from 30 to 45 degress becauuse there is so much slack on the motor and depends on the wind if it gets pushed or not.

They are also painfully slow and the motor needs to warm up before it speeds up to just slow.

UnseenCat
UnseenCat
1 year ago

What happens if the wiper blade is removed (possibly forcibly, by tree branches..) from the wiper arm? With normal wipers, the tension spring will press the end of the metal wiper arm against the glass, which will typically scrape the “arc of shame” permanently into the windshield with just a few wiper strokes.

From the video, it looks as if the lower part of the wiper arm is fairly close to the metal arch — close enough that, lacking the blade attached to it, the arm might contact the metal arch which would prevent the end of the arm from contacting and gouging the glass.

As for the tabs, ever notice that the slack in the wiper mechanism tends to make them sweep further at the ends of their travel when set to high speed? The tabs would keep a loose mechanism from flinging the wiper blade off the glass and over the edge onto the metal windshield frame… possibly damaging it in the process, even ripping it off, and therefore requiring the metal arch to do its potential job of keeping the end of the arm off the glass.

This seems like one of those classic engineering exercises in “We can’t find or build a wiper assembly that holds up like it should, so we’ll engineer this little doohickey that keeps the stupid thing from destroying itself or the windshield.”

Last edited 1 year ago by UnseenCat
Rob Spiteri
Rob Spiteri
1 year ago

I am Land Rover people but this is beyond my pay grade. I’ll stick with Disco knowledge

Bongo Friendee Harvey Park
Bongo Friendee Harvey Park
1 year ago
Reply to  Rob Spiteri

Maybe your feature should be named Disco Inferno.

https://www.youtube.com/watch?v=A_sY2rjxq6M

Alan Christensen
Alan Christensen
1 year ago

Lucas, Prince of Parkness.

Icouldntfindaclevername
Icouldntfindaclevername
1 year ago

Lucas…something something, old MGB owner, Lucas something something

Drive By Commenter
Drive By Commenter
1 year ago

Lucas knew the workers at Solihull were abusing their session drinking privileges. This was an assembly aid so the wipers made it onto the vehicle in about the right spot. Left? Right? Doesn’t matter, bolt it down and onto the next one.

Black Peter
Black Peter
1 year ago

Watching your video the wipers don’t even travel far enough to hit the tabs. However looking at images of the Series 1 with the window folded or video of it being folded I can see/imagine three things; 1. the flip up front vents. 2 the actual window folding, 3 cargo/material on the hood. In the video linked below you can see the guy has to watch the wipers and adjust them as the window folds, then comparing the video you linked you can see your video guy’s wipers would not be in a good spot to clear the folding window. maybe if that’s the case and you’re in a rush the tab prevents the arm from over extending and breaking something in the motor assembly. Same with “stuff” piled on the hood, like Finnish fire hose (is that reindeer skin?) something that might hit the wiper arm and damage the motor. What the arc is for; no clue… just a way to put the tabs in the right spot but clear the wiper arm axel? Over engineering solution to an under-engineered wiper assembly?

https://youtu.be/AsPEShh5AuM

Alan Christensen
Alan Christensen
1 year ago
Reply to  Black Peter

Is there enough slack in the arm movement to tuck the wipers UNDER the tabs so they’re in the proper position for folding the windscreen?

Jack Trade
Jack Trade
1 year ago

It reminds me of the little prongs some analog gauges have inside them at the extremes of the register.

Jakob K's Garage
Jakob K's Garage
1 year ago

A guard so the wiper arm doesn’t smash too hard into the probably delicate non laminated windscreens.
On a real off road vehicle you quite often lift the wipers to clean the screen for mud and dirt.

Or maybe it’s a noise maker. Everything else in an old Land Rover makes lots of noise, and this is a quick fix for using a regular british not very noisy Lucas wiper motor in a Land Rover: The wiper arm scratches the guard metal when it is moving back and forth, making a very Land Rover’y squeaking noise.

Last edited 1 year ago by Jakob K's Garage
Arch Duke Maxyenko
Arch Duke Maxyenko
1 year ago

It’s actually an emergency pizza cutter. Let’s say you’re out in the field and you just got a nice piping hot pie delivered to you, but those lazyass teenagers didn’t properly cut through the crust all the way. Now what are you going to do? It’s easy, simply unbolt the emergency cutter off your windshield and rock it over the uncut sections, then presto, perfectly sliced pizza! This new and improved version you see here is automatically sharpened every time you use your wipers! Call now to order your Safari Pizza Cutter for the low, low price of $19.95! (plus shipping and handling) But wait, if you order within the next 5 minutes, we’ll double your offer and give you 2 Safari Pizza Cutters! (plus additional shipping and handling) So call now and never be without sliced pizza again!

(Arch Duke Maxyenko is a non attorney paid spokesperson and is no way responsible for any and all claims.)

Crank Shaft
Crank Shaft
1 year ago

I suspect it either helps the internal mechanism with reversing or saves some part from getting over-stressed when reversing.

Non-sequitur: What happened with the Pao ball joint? I for one am still curious.

Last edited 1 year ago by Crank Shaft
CSRoad
CSRoad
1 year ago
Reply to  Crank Shaft

It’s Lucas the physical resistance probably triggers a “switch” of polarity in the motor reversing direction of the wiper. What could go wrong?

Crank Shaft
Crank Shaft
1 year ago
Reply to  CSRoad

Have you heard of Lucas Magic Smoke? I have a jar which I might be willing to part with for the right price.

WaxhawFive
WaxhawFive
1 year ago

Something to do with folding windshields? To prevent the wiper from accidentally sweeping INTO the passenger area when the windshield is down?

PL71 Enthusiast
PL71 Enthusiast
1 year ago
Reply to  WaxhawFive

I like this idea for cars where it’s really removable

T-Keith
T-Keith
1 year ago

GM used to use a park function on it’s blades. The motor reversed which ran a cam that lifted the blades off the windshield to preserve the blades and prevent icing.(This is why they didn’t tilt up) Perhaps this fuffills a similar function.

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