PorKen

700 bucks for a new wiper motor! F*ck that! $7 = better.


Usually, the only thing wrong with a slow/noisy/inop motor is a bad bearing. Replacing the bearing is a messy, fiddly, job, but worth the effort. The brushes usually have plenty of life left in them. I've rebuilt two so far, and they work great. Faster/no more reee-wrrrr, reee-wrrr, reee-wrrrr...


Bearing dims are 10 x 26 x 8mm. Standard bearing #6000. I used a 6000 2RS C3 (sealed both sides).


You can remove the wiper assembly without taking off the hood, but it takes some wiggling. Remove the wiper arms, windshield side trim, cowl to access the 22mm (7/8") nuts. (See WSM 92-6.)

Now is a good time to remove the blower too, and hose out the valley of muck. Check for 'easter eggs' in the fender. Don't lose the washers which go between the fender and the body.

Remove and disassemble the motor. Spray the outside of the bearing with PB-Blaster or other penetrating oil. Mark the position of the slot on the plastic set screw and remove. Use one of the mounting screws to drive out the armature with attached bearing. (Red line in pic.)

Carefully push the rubber brush mounting board isolators through the board. Unscrew the ground terminal.

Remove the outer bearing circlip. Use a bearing puller to remove bearing.

I didn't have a bearing puller. I crushed the outer shell of the bearing in a vice, then worked the inner race off by turning the armature which took a while.

Brush/vacuum out the motor case (coat inside with WD-40), clean the armature, lightly sand the commutator and clean out it's grooves. Try to enjoy the hour or more it takes to put the brush assembly back on. Remember that the board goes toward the trans! Doh! It does fit over the bearing. Oops! Drive on new bearing, replace circlip. Brush antiseize on the outside of the bearing. Slide armature into transmission. Carefully pull isolators through board. Clean and reattach ground wire. Slide on cover. Take care not to pull the armature and bearing out of the trans by the pull of the permanent magnets. If you get lucky, you may get the armature into the rear bushing the first or second time. Or the twentieth.

Grease transmission. Install plastic set screw. Attach cover. Plug motor into harness. Turn key to 'on', and cycle motor to check that it works. Turn wipers off before shutting off key or unplugging motor. Let it park properly. Don't be surprised that you can no longer hear it, and that it turns much slower than you'd think.

Use strip caulk to seal the motor all the way around the cover seam and fasteners. Install motor in wiper assembly.

Install and adjust wiper position. You may have to unbolt and adjust the arm at the motor/wiper arms a few times in order to get the wipers to park smoothly with no extra up or down movement.


Note: pics are of a '85-up motor - 944 628 303 01

Landseer

Thanks Ken.

BC

Any idea as to how make the highest setting faster?

Dave928S

Looks like water in the motor + time stuffed the bearing ... thanks for the explanation and pics

PorKen

Ceramic bearing?

I might try one, next time. Maybe not this bad boy, but ceramic.


VXB Silicone Carbide $110

Tails

Ken,
Thanks for the write up and pictures. 928 library getting larger.
Tails 1990 928S4 Auto

borland

It's a 944 part for 928's in vintage 85'-95'. Used ones sell about $50 on eBay. The factory plastic under hood tray should protect the motor from getting too wet.

There are some more motor take apart photos on this 944 thread...

https://rennlist.com/forums/924-931-...with-pics.html

PorKen

I would replace the bearing on any used one. The OEM bearing is unsealed.

There's a local to me $50 assembly on ebay. I've thought about buying it for a drop-in replacement. It would be a good candidate for a ceramic bearing trial...

The rusty motor in the pics came from my '86.5 which has had a new cover since I bought it. The strip caulk should help.

Imo000

Yup, did this on the '83 10 years ago. Easy as pie!

Bizman928

I wrote a similar write up for the TIPEC magazine in the UK earlier this year.
Here is a link with some photo's if your interested?

http://cid-70d4844dc8c361fd.photos.l...r%20Motor?uc=1

Cheers
Steve

MY89 928 S4 Stone Grey Metallic....gone but not forgotten......

My New 928 :-
MY88 928 S4 Auto - Black Analogue Dash .....- Back in 928 S4 ownership!

PorKen

Very nice, thanks! Some good tips there.

I converted it to PDF, reduced the file size, and put it on the rennlist server.

(WiperMotorRepair.pdf) 3.7Mb

borland

Nice job on both the writeup and PDF file.

For removing the bearing from the shaft, you could use a small bearing puller. Places like Autozone or O'Reilly Auto Parts have small bearings pullers that can be used at no cost, as part of their Tool Loaner Programs.

Bizman928

Thanks for the kind comments PorKen & Borland. Hope this helps anyone with this repair.

Steve

MY89 928 S4 Stone Grey Metallic....gone but not forgotten......

My New 928 :-
MY88 928 S4 Auto - Black Analogue Dash .....- Back in 928 S4 ownership!

mark kibort

let me know if anyone needs a wiper motor. I think I have a few extras.

Landseer

Early cars also accept early 944 motors but require a little bit of rewiring due to different connectors.