Date: Sun, 15 Jan 2012 18:01:01 -0600
Reply-To: James Felder <jim.felder@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: James Felder <jim.felder@GMAIL.COM>
Subject: Re: Heater blower motor questions
In-Reply-To: <4f134d81.c3bde00a.66b5.ffffdfab@mx.google.com>
Content-Type: text/plain; charset=utf-8
Excellent instructions, David. I will get on it… just a question, though. Why not emery cloth?
Thanks,
Jim
On Jan 15, 2012, at 4:04 PM, David Beierl <dbeierl@attglobal.net> wrote:
> At 03:25 PM 1/15/2012, Jim Felder wrote:
>> Is there a way to get—or any point in getting—behind the blower end of the
>> frame and armature?
>
> All blower motors that I've freed up have lasted years without further problems.
>
> Procedure as follows: see https://picasaweb.google.com/dbeierl/VanagonAnatomyOfABOSCHHeaterBlowerMotor?authuser=0&feat=directlink for photos of the motor.
>
> Note - it's been a while since I've done this, so I may be off in some detail.
>
> 1) Split blower housing by releasing tabs.
>
> 2) remove wire clips holding motor into plastic sleeve. Mark the motor orientation in the housing. Place housing on the open jaws of a vise or other support so that the jaws support the motor sleeve but don't cover the edge of the motor. Remember you will need room for the motor to fall from the sleeve.
>
> 3) Press the blower wheel down and verify that the motor moves reasonably easily in the sleeve. Get the edges of the motor past the vise jaws and adjust vise for maximum support.
>
> 4) Note how far the blower is inserted onto the shaft. Using a drift and large hammer, tap the motor shaft out of the blower wheel. Make *sure* that the edge of the motor isn't catching. As you near the end the shaft will drive easier. Get a hand underneath to catch the motor as it falls out, as it will be damaged if it drops end-first onto a hard surface. Set the wheel aside, being careful not to dislodge any metal balancing clips on the blades.
>
> 5) Examine motor. All the ones I fixed had brushes worn 1/4 or less and were seized up. Commutators looked good. A motor that screams horribly (bearing chatter) when started needs new bearings and cannot be repaired in practical terms.
>
> 6) Drop Marvel Mystery Oil or similar outside each end and work the shaft in and out and rotate it. Wipe off crud as it emerges and re-oil. Run the motor for a few seconds. Wiggle, wipe, oil, run etc. for several cycles until no further crud emerges. When motor turns sweetly...
>
> 7) Soak up MMO as much as possible. Lube inside and outside of shaft with light machine oil (Supco MO98 turbine oil is good), and fill the felt ring inside each bearing with oil (see photos).
>
> 8) Clean and dry commutator. Brake cleaner on a rag is good. If necessary (probably not) sand lightly with very fine sandpaper (800 grit is probably pretty good). Do not use emery. Gently scrape any junk from between the commutator segments with a soft tool that will not scratch or deform the copper. Clean and dry again if needed.
>
> 9) Run motor on the bench for a couple days, checking periodically. If more crud comes out wipe it from inside and outside and add clean oil. There should not be much sparking at the commutator - trails of sparks indicate conductive material still between the commutator segments.
>
> 10) Observing orientation, press motor back into the housing.
>
> 11) Rest the motor shaft on a hard heavy surface and use a hammer and block of wood to tap the blower wheel back onto the shaft. Set the depth the same way as before it was removed.
>
> 12) Replace the wire clips holding the motor in.
>
> 13) Before closing up the housing, run the motor and make sure all is well and wheel is balanced. Close up the housing.
>
> 14 - Load test motor. The Bosch blowers I've tested draw about twelve amps from a fully charged battery (engine not running/charger not charging).
>
> [15) - glue protective cap over the end of the motor. If you cover the entire end, leave a hole for ventilation.]
>
>
>
>> Now it runs like a top, but I would like to know more about the condition,
>> like how much current should it be drawing. How do I accomplish that? I
>> have voltmeters but need to improve my ability to use them.
>
> You need a meter that will measure more than 10 amps DC. Place it in series with one lead to the motor. If you don't have access to such a meter you can build a shunt out of copper wire and use your 200 mV digital voltmeter to measure across it. More later if you need it.
>
>
>> Finally, is the front blower motor different from the rear.
>
> Yep. Rear is smaller.
>
> Yours,
> David
| 
