The Stovebolt Site Forums The Shop Area Interiors Vacuum wiper motor question᠁

Guys, I’ve got a 1948 3100. I’m chasing a vacuum leak on a 327 with TBI/throttle body injection. I’m still using the vacuum wiper motor as it still works well enough for the few times I’ve ever been in the rain. My question tho, is: when the wipers are not being used should the vacuum motor leak any vacuum? I’ve hooked up my hand vacuum pump to the motor (still under the dash) and with the motor switch in the “OFF” position my hand vacuum pump will not build up any vacuum. Does anyone have your vacuum wiper motor on the bench and could you hook up a vacuum pump to it? What kind of seal is on that switch port at the motor and should it hold vacuum? A picture would be cool. Thanks in advance. Dave

If it turns out you think it is a problem, send it to Ficken Wiper Service. He will rebuild it for like $135


https://rebuildingtricowipers.com/

The slide switch on top of the vacuum motor shouldn't leak when it's off. I had a motor that worked 'OK' (or I thought it did.) I sent it to Fiken and it works WAY better. Money well spent.

Dragsix, klhansen, thanks for the Fiken Wiper Service recommendation, but my Mancard requires that I try to repair the vacuum wiper motor myself before I send it off to somebody else. Again, I’m asking if someone can hook up a hand vacuum pump to the motor and see how well that slide switch on the motor holds vacuum in the “OFF” position. Thanks in advance, Dave.

Why not disconnect the vacuum line to the wiper motor and see if the fixes the vacuum problem on the engine. If it does you have isolated the problem.

1Series: I did that prior to my road test yesterday᠁.plugged the vacuum hose to the wiper motor; the engine ran great. I’m just following up now to decide where to go next with that Trico motor. I’ve read a number of posts about electric replacements. I’m not too encouraged by what I’ve read. I’d prefer to stay with the vacuum motor. I’m finding that there are rebuild kits available on line.

Looking for a rebuild kit also. Good luck in your search. It seems most places want to convert to electric rather than repair the originals.

Just ordered a kit for $10 on EBay. If it doesn't work I always have the option of sending it to Fiken for rebuild.

I totally understand that.
The problem is that there aren't real repair kits available, and Rob Fiken doesn't sell them (protecting his business, which I understand.) The only thing you can get is gaskets, but the seals on the paddle are typically what makes them next to impossible to repair. Even getting the paddle back in with the seals correctly oriented (even if they're intact) is problematic. I've tried and failed.

klhansen, I’ve been researching the rebuild and I too am seeing that the paddle switch/seal is problematic and also that a complete kit appears to not be available. My wiper works “OK” as I mentioned earlier, except the vacuum leak at the paddle switch when “OFF” is the only problem. I would submit that anyone still using the vacuum wiper motor might want to test for a vacuum leak at that interface. I’ve got a “work-around” in mind if I can’t correct that vacuum leak᠁.or consider the Fiken option.

I'll try and dig out my spare vacuum motor and run some tests on it. I've tested them using a vacuum bag sealer, but it doesn't have a real gauge on it. I can hook up my Mity-Vac and see what it tells me. Give me a day or two.

Thanks Kevin.

OK, I dug out my spare motors. Neither of them really held vacuum, but one was one that I sent to Fiken for him to scavenge parts from. It was missing the switching mechanism and some of the unique screws. I didn't really expect him to return it to me. Anyway, I plugged the inlet nipple, and applied vacuum across the on-off slide switch of that one and it would pull up to 15 inches of mercury and then slowly leak down. If I applied pressure to the top of the slide switch, helping it seal against the body, it would do a bit better (slower leak down.) There's another leak path at the direction switching mechanism where a toggle slides across three ports to connect the source with either side of the paddle. When the wiper is in park, the flow path is thru the slide switch, directly to the park side and the seal that's on the paddle, and bypassing the switching toggle.
In any case, unless there's significant deterioration in the motor, I don't think the loss of vacuum would really be enough to affect engine performance. The lubricant in them is kind of a waxy stuff that should help seal the slide switch and the toggle (the vacuum itself should hold the switches against their seats on the motor body.)

Attached are a few pics I took to show the inner workings of the motors.

Kevin, thanks for the great pictures. Is that troublesome leather seal at the park paddle then? And at that slide switch how is that interface sealed? Is it just metal-to-metal contact or is there some seal there also? If the Mityvac won’t hold vacuum in “PARK” where do you think the leak would be?

I think the park seal on the paddle is pretty durable, but the slide switch may be the leak issue. It's a phenolic block that slides over the pot metal housing, with a bit of that waxy lube on it. It could be that the spring that pushes the switch block down on the body could be a little weak. You might try carefully bending it a little more so that it pushes harder when screwed in place. I don't know what type of lube is used, but if you could find something similar, that might help too. Opening the body up is an iffy proposition in getting the paddle seals back in place correctly, but taking the top off without removing the paddle is probably doable. You can see that the paddle is riveted together, so unless you can come up with a way to replace those, restoring the paddle seals is going to be tough. That's a job I'd leave to Fiken.

Since this thread is mainly about wiper motors, I'm moving it over to Interiors.

Kevin, with the info I’ve collected thru this post, and your pictures and advice, I think I’ll jump in and tackle that vacuum motor. I’d taken it out and apart maybe 25+ years ago just to freshen it up so it’s over-due for some tlc. What can possibly go wrong? And my ManCard needs some exercise. Kevin, thanks for your help, I’ll update this post when I get further along with the R&R᠁.