My anemic vacuum-powered windshield wipers...

[Richard Chapman]

Does anyone have any ideas about getting a little more oomph out of
Trico vacuum-powered windshield wiper motors? I've lubricated everything in
sight external to the motor, made sure that there isn't any vacuum
leaking out between the engine and the motor, but the wipers still stall
about mid-stroke every so often. I wet down the windshield good and rev the
engine, they don't stall, so I think I only need a little more power
(something tells me that when I go to get it inspected that the
inspector won't go for the "They work fine during the rain at highway
speed" argument).

I have not, however, done anything to the motor itself, since I have no
idea what to expect inside it. I have a source for a "rebuild" kit for
Trico vacuum wiper motors -- is this worth a try? What about the electric
replacement for this thing -- is it much more powerful?
Newsgroups: alt.antique.autos
Subject: I _luv_ vacuum-powered windshield wipers
Distribution: world
Organization: Cornell Univ. CS Dept, Ithaca NY 14853

Does anyone have any ideas about getting a little more oomph out of
Trico vacuum-powered windshield wiper motors? I've lubricated
everything in sight external to the motor, made sure that there isn't
any vacuum leaking out between the engine and the motor, but the
wipers still stall about mid-way between changing directions every so
often. If I wet down the windshield good and rev the engine, they don't
stall, so I think I only need a little more power (something tells me
that when I go to get it inspected that the inspector won't go for the
"They work fine during the rain at highway speed" argument).

I have not, however, done anything to the motor itself, since I have
no idea what to expect inside it. I have a source for a "rebuild" kit
for Trico vacuum wiper motors -- is this worth a try? What about the
electric replacement for this motor that Pro Antique Auto sells -- is
it much more powerful?

[James W. Swonger]

Is your idle vacuum a bit low these days? A check of that might be worth
doing. If it's way down you may need a tune-up or something. If you have
put in a hotter cam that'll depress idle vacuum big time.

If the vacuum motor is a reciprocating diaphragm type, check said
diaphragm for leaks. Also check the hose; is anything elso on the
vacuum accessory hose bleeding off vacuum? Lots of cars run things like
vent actuators off one accumulator with a restricted feed. Any leak
could sap a high-demand vacuum appliance.

--
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[Ted Brooks]

In article <1992Jul17.1...@cs.cornell.edu>, cha...@cs.cornell.edu (Richard Chapman) writes:
>
> Does anyone have any ideas about getting a little more oomph out of
> Trico vacuum-powered windshield wiper motors? I've lubricated everything in
> sight external to the motor, made sure that there isn't any vacuum
> leaking out between the engine and the motor, but the wipers still stall
> about mid-stroke every so often. I wet down the windshield good and rev the
> engine, they don't stall, so I think I only need a little more power
> (something tells me that when I go to get it inspected that the
> inspector won't go for the "They work fine during the rain at highway
> speed" argument).
>
> I have not, however, done anything to the motor itself, since I have no
> idea what to expect inside it. I have a source for a "rebuild" kit for
> Trico vacuum wiper motors -- is this worth a try? What about the electric
> replacement for this thing -- is it much more powerful?
> Newsgroups: alt.antique.autos
> Subject: I _luv_ vacuum-powered windshield wipers
> Distribution: world
> Organization: Cornell Univ. CS Dept, Ithaca NY 14853
>
> Does anyone have any ideas about getting a little more oomph out of
> Trico vacuum-powered windshield wiper motors? I've lubricated
>

> I have not, however, done anything to the motor itself, since I have
> no idea what to expect inside it. I have a source for a "rebuild" kit
> for Trico vacuum wiper motors -- is this worth a try? What about the
> electric replacement for this motor that Pro Antique Auto sells -- is
> it much more powerful?

It's probably time to tear into the motor - carefully. Check out the rebuild
kit - I wasn't aware they were available. Would you mind posting the source
for the benefit of the others on the net?

If no rebuild kit is available, I have seen old Chevy vacuum motors revived
as follows. Carefully take the top off the motor. There is a cavity in there
which contains a flapper with a rubber seal around it. There will also be
some sort of very small, cam operated mechanism to select one of two vacuum
holes. (This mechanism reverses the direction.) Since your motor works, I
would check the flapper seal and repair any tears with silicone rubber. Then
clean the cavity and lightly grease with special high temperature grease .
Use the type auto parts stores sell for lubricating the friction points in
brake systems. Standard chassis grease will thicken too much when the
temperature drops outside, causing the unit to stall. Check the cam
mechanism & vacuum holes for cleanliness, and reassemble the top cover
using some Form-a-Gasket to get a good seal. Good luck!

Ted Brooks
______________________________________________________________________
| Disclaimer: The opinions expressed are my own, and do not reflect |
| those of my employer. Advice is free, but you get what you pay for. |
| ________ |
| _____| 1955 |_______ |
| / Chevrolet / |
| /______ BelAir _____/ |
| |________| |
|______________________________________________________________________|

[Geof Evans]

<<<* Yes the electric update *will* solve your problem...your question
about "will it be more powerful ?" leads me to believe that you don't
quite know the basic operating principle of your "vac wipes".
A little *slowinging down* is quite normal as you accellerate or
give the engine a little gas, or even a total (momentary) *stall*
if you really give it a serve, even when the wiper motor was brand new.
This is due to the fact that they work off manifold vacumn to pressurize
a diaphram in the wiper motor, it's like a little vacumn pump. When you
"give it some gas" there is precious little manifold vacumn left due to
that great lumbering V8's need for all the air it can get. That is why
the wipers return to speed when you *back off* a little, such as cruising
on the highway. This is all very normal for vacumn wipers and was once,
when electric wipers were rare or unheard of, quite acceptable to most.
You gotta admit they have got *character* !!!

--
___________________________________________________________________
|| Geof Evans | DOMAIN: rxk...@minyos.xx.rmit.oz.au ||
|| Melbourne,Australia 3000 | Tel: +61 3 663 3663 ||
|| If they *really* wanna know...tell 'em that God was drunk. ||
||___________________________________________________________________||

[Mark Muirhead .moo!.]

cha...@cs.cornell.edu (Richard Chapman) writes:

|Does anyone have any ideas about getting a little more oomph out of
|Trico vacuum-powered windshield wiper motors? I've lubricated everything in
|sight external to the motor, made sure that there isn't any vacuum
|leaking out between the engine and the motor, but the wipers still stall
|about mid-stroke every so often. I wet down the windshield good and rev the

This does sound like a typical acceleration stall; as the engine revs,
the manifold vacuum drops. Have you run a guage over the manifold? You
might have a leak somewhere else (or the engine could be getting tired).

|I have not, however, done anything to the motor itself, since I have no
|idea what to expect inside it. I have a source for a "rebuild" kit for
|Trico vacuum wiper motors -- is this worth a try? What about the electric
|replacement for this thing -- is it much more powerful?

You can't really go wrong having a play with the motor, from memory, there
aren't that many bits and pieces to lose!

On the other hand, I've got a '50 Stude. at home with an after market
vacuum pump which sits between the manifold and the wiper, when vacuum is
a bit low, turn on the pump and away it goes. (It's a period after market
item, so I don't know if they're still available)

I'd be very interested in a re-co kit for the wipers though.

Cheers,

Mark.

[Bryan Blackwell]

Depending on how stock you want the car to stay - I assume so, since you want to keep the vacuum wipers - this may not be what you want, but another possibility is a vacuum resevoir. It's basically a can with one-way valves in it so that there's vacuum available for accessories (mainly brakes) on cars which don't have a lot of vacuum at idle. You can get one at a speed shop or other high-po parts supplier. High performance engines typically don't have a lot of vacuum, so this is a fairly common item; Mo

roso makes a nice looking one, you could even build your own pretty easily.

[Ted Brooks]

In article <13...@goanna.cs.rmit.oz.au>, m...@goanna.cs.rmit.oz.au (Mark Muirhead .moo!.) writes:

> cha...@cs.cornell.edu (Richard Chapman) writes:
>
>
> This does sound like a typical acceleration stall; as the engine revs,
> the manifold vacuum drops. Have you run a guage over the manifold? You
> might have a leak somewhere else (or the engine could be getting tired).
>

I second the motion. Keep in mind that even a "perfect condition" vacuum
motor will slow or stall when the manifold vacuum drops off. Therefore, a
"problematic" stall situation is a relative term.

> On the other hand, I've got a '50 Stude. at home with an after market
> vacuum pump which sits between the manifold and the wiper, when vacuum is
> a bit low, turn on the pump and away it goes. (It's a period after market
> item, so I don't know if they're still available)
>

There's also double action fuel pumps available for many models that have a
similar function. One side pumps the fuel; one side provides a bit of
extra vacuum for the wiper motor.

[Ted Brooks]

In article <1992Jul17.1...@cs.cornell.edu>, cha...@cs.cornell.edu (Richard Chapman) writes:
>

> often. If I wet down the windshield good and rev the engine, they don't
> stall, so I think I only need a little more power (something tells me
> that when I go to get it inspected that the inspector won't go for the
> "They work fine during the rain at highway speed" argument).

One consideration on the inspection issue - they will probably test the
wipers while the engine is idling. That's good, because that's when there
should be the most engine vacuum available. If they don't work right when
the engine's idling, then you definitely need to look into it.