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MG MGB Technical - '77 B windscreen wiper problem

Hi Everyone,

I've got a '77 B that has a slow and noisy windscreen wiper motor. I read a couple of posts from the archives, but they covered single speed motors found on earlier B's. I'm going to go through and check all of the electrical connections first, then maybe take the wiper rack out to clean it and put in new grease. If that doesn't fix it, I guess I'll need a new motor.

Any thoughts?

Dave Plantz

Looks like you're on the right track. When I restored my '74 a while back, the motor wouldn't park when switched off. While the unit was out of the car, I took it apart and just cleaned out the gear box and put in new grease.

After reassembly, the wipers worked fine.

I've just finished a V8 project on a '77 roadster and did the same thing with it's wiper motor. I never knew if the motor worked as the car was just a shell when I bought it. After reassembly, I bench-tested it with wires from a battery charger. Check out a wiring diagram for the proper connections. This will tell you if your work was successful before you re-install it.

While you have it out (if it comes to that), clean and re-grease the wheel boxes and get some oil in the shaft that runs through the tube as well.

Chances are it's just old grease that's dried up in there.

Simon Austin

Hi Simon,

What's the easiest way to remove the wiper motor and rack? I'm going to be taking the dash out soon anyway to replace it with a better one, so I'm thinking of pulling the wiper motor then. What did you use to clean out the old grease? Will white lithium grease work for reassembly?

Thanks for your help.

Dave Plantz

When you get the dash out, half the battle is over. The wiper assembly is held in place by the three wheel boxes and a u-shaped bracket wrapped around the motor. You can see the bracket if you peer up under the dash on the passenger side.

The electric plug is attached to the motor on the side next to the firewall (couldn't put it on the side where one could get at it, could they?)

The wheel boxes are held on by nuts on the outside of the car just under the wiper arms. I've found the nuts usually get damaged as they come off so new ones are a good idea.

I've used Q-tips to swab out the grease and then just a cleaning product like "Super-Clean" or carb cleaner to get the residue out. White lithium grease works fine as it's not too thick. It's worked fine for 7 years on my '74.

Let us know how you make out. I purchased a new dash from Moss that comes as a new pad with foam and you attach it to your old steel part. What a difference! You have to cut out the holes but it looks great.

Simon Austin

Hi Simon

I too have some work to do on the wiper assembly so I have been following this thread with some interest.
Is it possible to remove the wiper assembly without removing the dash?? And of course can it be re-fitted with the dash in place?

Bruce Mills

Hi Bruce,

Are you sure there isn't something you'd like to do on your dash that only removing it would solve??

I'm kidding but only just. I've only ever worked on my wiper motors without the dash in place but sitting here thinking; how hard would it be to get the motor and wheel boxes out?

Once the nuts are off the three wiper assemblies (wheel boxes), they will just push through the panel so that's easy enough. Getting the whole assembly out shouldn't be a huge problem once the bracket is removed ("he says obviously..."). The only place I can see getting the shaft caught is on the face-level vent tubes, but with careful maneouvring, I'm sure it will come out.

Once it is all said and done and you're ready to re-install, the fun will begin with getting the three boxes lined up with their respective holes and pushed through.

Removing the glove box should help with the passenger side unit and maybe the middle one but the driver's side will be the worst. Don't forget about the defroster vents sitting there just ready to be your worst nightmare.

Didn't a recent thread "Worst jobs on an MGB" sum it up and state "anything to do with the dash or under it?"

Hope this helps and remember to keep telling yourself as you're doing the work: "I love my car and what's it's doing to me!"

Simon Austin

This thread was discussed between 30/04/2005 and 02/05/2005

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