Wiper motor 100 degree sweep gear ???

[Jerry]

My wiper motor sweeps too far and goes off the windshield. IE: starts next to rubber, and goes beyond the rubber at the other side. It currently has a 105 degree gear. I found on a lucas site that there is a 100 degree gear out there. Anybody know what car that would be in? Or has a gear laying around?

Jerry
This is for a an old mini

 

[TR3driver]

Do you know the wiper motor type (eg DR3)? I've got an old Lucas master catalog from 1960 that lists many different gears, from 90 all the way to 150. It also lists "large gear wheelboxes", that reduce the angle by 30% or so.

A quick scan only turned up one DR3 with a 100 degree gear. The motor model is 75356D, application is listed as "Rover 3 litre, 59-60".

DR2 with 100 degree gear: 75295
Alfa Romeo 'Giulietta Spyder' 1956.

Morris 'Minor 1000' and 'Traveller' 1958-60;
'Cowley' 1955-57;
'Oxford' and 'Traveller' 1954-57;
'Isis' 1956-57;
Quarter Ton Van and Pick-up Truck 1958-60;
Quarter Ton Van (G. P.O.) 1960;
Half Ton Van and Pick-up Truck 1957.

Simca 'Arondc' De Luxe, 'Oceanc' and 'Plien Cicl' 1959.


Also, 75300 DR2. 12v.
Austin 152 Range 1957.
Morris Commercial 'J2' Van. Pick-up Truck and 'Minibus' 1957-58.

PS, another thought: I had a similar problem on a TR3A that appeared to be due to wear in the mechanism somewhere. It wouldn't happen with the glass dry, but in the rain the wipers would overtravel onto the windshield frame. Flipping the rack over greatly reduced the problem.

 

[Jerry]

I have the two speed mini motor. This is a copy of the original. Usually sold on British cars in the late 60s.
https://www.minimania.com/part/GEU7708/Wiper-Motor-2-Speed-Mkii-Mini--Mini-Cooper-And-Later

Now, Of your list above, only the Morris models might be easy to find around here. The older wiper motors have a larger gear (diameter) IE: my TR3 extra motor and gear will not swap into the mini motor. So I tried to solve the problem with math. The 110 degree gear has the post 0.67 from the center of the gear. The 105 degree gear has it 0.62. So I guessed at what a 100 degree motor and came up with 0.57. So far that was easy. Then I had to pry apart the plastic gear from the metal piece that goes through the middle. I drilled out the post, moved it to the new distance and welded it back on. Grinding a little to remove the extra welds and put it into the car. It is better but still marginal rubber to rubber. I will have to try it in the rain, there is too much pressure on the windshield to keep the motor running when it is dry.
I am wondering if the rack is really a right hand drive rack, and was flipped over for my left had drive car. I think this whole process might work better if the wiper itself was taller up the windshield and left the bottom part wet. But that would be another experiment on the wiper arm and I don't have stainless sitting around.

Testing the process tomorrow as it is finally raining in Northern California.

Jerry

 

[Deleted member 8987]

According to friends that have owned them, LHD/RHD swap is mostly flipping parts over.
On RHD/LHD wipers on my era Jag, the motor needs to have the field reversed, and the park switch in the motor reversed, since when you shut the wipers off the motor runs backwards, there is an offset drag part that changes the sweep, and it parks against the windscreen trim.
I don't know if Minis did the revering and park bit. You'd know if when shutting them off, most of the time it does a second sweep and comes down further...plus RHD jags park on the rights (different arm bends), LHD parks on the left.
I have a motor here that was in the Jag when I got it. Single speed, which is wrong, park switch removed..I think it was a Morris, if I recall the numbering. Maybe the gear is what you need. Have a part number on the gear you want? I'll check later.
Dave

 

[TR3driver]

Yeah, the gears only interchange within the same type and that is one of the later type motors with the permanent magnet field (probably 14W, not sure). So I wouldn't expect the gear from the DR2 or DR3 in your TR3 to fit the later motor. It's supposed to be 130 degree sweep anyway.

For TR6, it appears that the motor itself is the same between LHD and RHD, but the gear is different. Seems like the sweep would have to be the same, though, so maybe the gear change is something to do with the park switch.

Sorry I can't be more help, none of my later Lucas catalogs show the sweep angle and I mostly only collect Triumph stuff.

 

[Jerry]

Well to give you guys some feedback. The wipers work pretty well for about 5 min, then the bottom 2 inchs of the rubber causes too much friction on the bottom windshield rubber and they start. I can get them started again by flipping to the high speed. It is like the NEW motor is overheating and needs a rest. Since I really don't drive in the rain much, I am considering trimming the bottom of the blade by a 1/16 of an inch to release some friction. I only look out the top of the windshield anyway. I was thinking of turning the wiper boxes around, but my notes said I have already tried that. They still sit at a funny angle, so I wonder if there is a problem there. I did have them all apart, cleaned and greased and painted the outside tubes.

Jerry

 

[TR3driver]

These might be of some help
https://www.amazon.com/Anco-4101-Wiper-Adjustable-Arm/dp/B0009IK5Y4
Although the minimum length is advertised as 8", the ones I have could be fairly easily modified down to 7" (from center of the spindle to center of the blade attachment). And the length is continuously adjustable (a clamp mechanism) as well as the blade angle.

They shouldn't be running rubber on rubber at all. Perhaps the blades you have are longer than the originals? I know that was a problem with TR3 at one time; the replacement blades offered by ANCO etc were longer than original and would hit the edge of the convertible top. I used to buy extra long refills and cut them in half to make the refills I needed.

If you haven't already done so, soaking the motor bushings in oil might help. Also check that the armature has some end play. On the earlier Lucas motors, there was an adjustment screw, but probably just washers on your later one. Your manual should have a spec, but if not, shoot for around .008".

Obviously, the motor overheating probably indicates extra physical resistance in the system. There should be a test procedure somewhere. For example, the TR6 workshop manual gives a procedure to check the unloaded (link removed) motor current draw (1.5 amps low, 2.0 amps high) and speed (46-52 rpm low, 60-70 rpm high). Then it says to measure the force required to move the rack with the blades removed (no more than 6 lbf). On my (former) TR3A, I had an almost invisible dent in the curved section of the guide tube that was causing the rack to bind in the tube.

 

[Jerry]

That adjustable wiper blade is perfect. I have an inch at the top of the screen that is not wiped and some at the bottom that is overwiped. (is that a word?)

No adjustment screw on the new motors. They did not even keep the round design accurate. Must be cheaper to manufacture that way.
I do have an original two speed motor that I can fiddle with and see if adjustments will make it run better. The park switch on it was cross connected and the new park switch were not made for that model. I made it fit with some short screws and JB weld but I was not happy with the long term prospects of my repair. Now that I have removed some of the friction, it might work better than the new replacement.

thanks for all the help, I will let you know if any other improvements show up. I think I will order some adjustable blades too.

jerry