@Superhawk996

lol!!! sorry to hear about the impeller fiasco! i am not sure how you would take the motor out without breaking the fan.
i just got the new blower from Al and the fan is free and clear and spins smoothly.
just tested the static resistance and i get, 2.6 & 4.4 but on the high circuit 2.5 with motor hooked up. without motor in the circuit, it’s 2.8 low, 4.2 medium and 1.7 high,- looks like low and medium should be switched, i am sure i have the contacts located correctly.- also tested between each circuit, so those were
5.2 between low-medium posts( the 2 resistors combined?) 4.6 low-high, 2.8 medium-high, . do those number look better than the other fan?

@Mikey914
@Superhawk996
man that seal looks good, that’s awesome you had made these you know they are not made by anyone else!!!
i am still going to try and figure out why the values on my fan are not correct and high circuit does not conduct, or complete a circuit but i got a good used one from Al Merideth, and it spins free, fins are perfect, and the test on the circuits is promising, so that will be the one we rebuild and put new seals in with the new kit coming.

Phil

@DRPHIL914

Sure looks a lot better than 121 ohms on high and/or 0.8 ohms on all three which are were two of the sort of random conditions that you had on the other motor assembly.

I'm wondering if you have some sort of resolution issue on you meter down at very low ohm setting. I have have serveral DMM's and a couple older analog multi-meters for special purposes. I have a cheap Sunpro DMM/Tach/Dwell meter that doesn't do well at low (sub 10 ohm) type work. Works great for Tach and dwell but I never trust it for resistance measurements.

Out of curiosity, when you touch the test leads together do you get something very close to zero ohms . . . like maybe 0.1 or 0.2 ohms? Is it repeatable?

The other thing that may be going on keeping high from showing lower resistance is the commutator may not be clean. I'd be curious if the resistance goes down after you run it on the bench for a few mintues and the brushes wipe across the commutator for a while.

FYI -- in the process of destroying my fan motor, it was clear that the brushes in mine are non-serviceable. The only real reason after that for wanting to remove the impeller was to try to get some lubrication on the rear bushing that is largely obscured by the impeller. I'll find a better way on the new unit coming.

I may order one of the fan motors from Pelican just so we can document how well those work and fit. Might be nice to have a brand spanking new motor. Probably will wait to see what shape this second fresh air box and blower is in that I just purchased as WTB before I pull the trigger on that idea.

Interesting that the end of your motor appear to be capped over the bushings. Mine weren't. Either the design had changed or someone had previously pulled them off my motor long ago when the housing was 1st opened, clips broken, and it was molested.

I'll snap some photos of my resistor pack tonight and we'll label each of the traces and reverify all pin connections.

Warning: Carnage that can ensue trying to disassemble the blower motor

First up someone was clearly here before and made some creative rubber seals for the blower motor control vanes.

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Looking forward to purchasing 914Rubber foam seals.

Should you decide to remove the impeller the 1st step is to get the spring clip off. I did it by gently prying the clip upward until I could get ahold of it with expanding snap ring pliers.

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In the cascading events that lead me to remove the motor from the housing / frame, it lead to a complete FUBAR situation. The permanent magnets and a bunch of spring clips that hold the magnets inside the housing came out along with the motor frame. I had assumed the permanent magnets would be secured to the housing. They were. However the glue that was holding them was so old, they just slipped right out of the frame along with the rest of the armature frame assembly. I don't see this ever going together properly again! Given the result, I would not recommend trying to remove the motor from the housing unless you're planning to replace the complete motor assembly.

Brushes weren't designed to be serviced, though it could be done if need be by unsoldering them, and carefully bending the retainers to get the brushes out. But, truly not designed for service.

The other is the motor shaft bushings are not designed for service. If they are worn and allowing side play and vibration like mine was, I don't really seee a viable way to service them even with the entire motor frame readily in my hand.

Click to view attachment

Can you post up some close up pics of the unserviceable part. Perhaps we can make a part that allows replacement of the one side that is an issue?

i was afraid of something like that happening when and if i got that circular spring clip off the back, i think it may be better to get a new assembly with motor and install that. the URO one i have seen as cheap as $83, on ebay and other sellers Pelican was the most at $95,
very creative on the flapper seals, the other box i rebuilt 2 years ago with the main body seal and flapper seals from 914rubber were a tight but proper fit and will make that work fine. I still have to pull that one out of my car because i have to go thru this whole process of testing the contacts like we are doing on these 2, thats the one that only runs on one speed, medium. I plan on rebuilding all 3 of these unless this resistor pack is bad on #1, if so i will have to buy a good used one from someone that may have one that the rest of the housing is not worth rebuilding or isnot going to.
I do get about .5-1 testing lead to lead, so it may be the numbers i reported are slightly hig

Note: Really need to remove resistor pack to do this properly.

When I removed mine, I found the low speed resistor bi-metallic switch was deformed closed. However, due to corrosion on the switch it was actually reading as if the switch were open. Can't assume anything.

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So reminder on the contact positions and keyway positions.

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Let's roll though the verification of the resistor

Here is the low speed after I filed the bi-metallic switch contact lightly with an ignition file. Because the bi-metallic switch is closed and now making contact it's measuring as a 1.1 ohm short across the resistor - bascially acting like a high speed bypass.

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Note: from here on out I have the resistor bank leads that would normally go to the motor shorted together in same manner as @DRPHIL914 was doing previously

Now low speed again with the bi-metallic switch bent back to open position with a pair of pliers to put it where it should be.

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Medium speed with bi-metallic switch open

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High speed (no resitor, and no bi-metallic switch for this one basically a direct short).

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Finally here is a picture of the orientation of the resistor bank connector and keyway as I photographed it in the photos above.

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I also did measure the armature of my now defunct motor -- the armature of the motor measured in the range of 0.8 ohms to 1.2 ohms depending on where it was rotated to.

So if you're measuring the resistor bank in the as installed postion, you would expect all values above to have 0.8 - 1.2 ohm added to them. This correlates pretty well to what I measured initially on my blower motor + resistor as an assembly.

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@Mikey914

Here is the motor frame.

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The motor brush is circled in red. In order to service it the tab would have to be bent open, the brush desoldered from the inductor / solder tab and then a new one installed. Not impossible but it's definately not designed for service.

The arrow pointing to the bushing on the open end of the motor does appear to have a small spot that can be oiled on some exposed felt. The impeller end of the motor frame doesn't have this same opening. Sort of makes sense since the impeller effectively prevents you from servicing that end of the motor.

On my blower motor I have excesive radial play in the impeller end bushing which would logically wear 1st since the impeller is cantilevered off this end. That radial play allowed it to vibrate and squeal intermittently until it warmed up.

The bushing is esentially staked into the pot metal motor frame. Wouldn't be easy to unstake it and then replace the bushing and re-stake. I'm a cheap SOB but really that would have been more work than I'd want to do. At that point, I really needed a new motor.

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Hope all this can help someone someday!

Bosch has motors listed for these. If you have removed the unit this far you can save a few $ and get the Bosch brand. I have seen them for al little as $65 at one point.

@Mikey914

Would be curious to see what you're thinking of. Do you have a part number?

I'll do a little digging too. I'm only aware of the URO part. However, I think it really does look like what maybe a off the shelf motor with some sort of molded adapter to fit this 914 blower housing frame that this smaller motor frame was a part of.

@Superhawk996
good work! the Bosch motor i have found on ebay, multiple sellers, about $75-85, and Bosch does the fan/motor assembly for about $250, so a few options depending on your time and $$ available.
i am going to get a URO assembly for one of these, i have one good motor/fan/resistor from Al , that one will get reassembled once cleaned and new seals all come from Mark and we will document the whole rebuild and assemble, retest and reinstall.
that will wait for a week as i will be gone this weekend and parts are not in yet.

The only thing you could have a problem with the URO part is the balancing "weights" I haven't seen any on their unit. Also the fins may not be identical to hold them on so if it's less and you can reuse your weights because you have disassembled far enough I would personally use the OEM.

For what it's worth good luck balancing one of these fan impellers.

They are dynamically balanced using a tachometer and an accelerometer.

You'll notice the impeller has degree markings on it. The tachometer keeps track of RPM as the impeller/motor assembly is spun. The accelerometer is used to find at what angle the peak acceleration occurs.

Knowing that information, a weight can be installed 180 degrees off of the peak acceleration. Rinse lather repeat until vibration is minimized.

Not easy to duplicate in our hobby garages. Static balance would achieve very little.

It can be done in a trial and error way in the same way you might balance a home ceiling fan with a penny. The problem with this is 1) they spin way faster which means a very small weight has quite a large effect. 2) They have so many vanes on the impeller you have a lot more trial and error options on where to place the weight. 3) Determination of minimal vibration becomes highly subjective.

My bet is that is why the OEM motor/impeller assembly costs the money it does vs. the URO assuming it isn't balanced.

makes sense , every one i have opened up has different amounts and local of metal clips on fins that i assume are the balancing weights .
good point on the balancing, maybe Drew aka @uropartsguy will chime in and tell us if any balance testing is done

The fan cage used in high quality URO Parts Blower Motor assembly 911 571 320 32 is indeed dynamically tested at the factory. Just pulled two random units off the shelf in the warehouse; one has a balancing clip and the other doesn't (probably didn't need it). Our impeller doesn't have degree marks, but it does have an arrow mark that's aligned with a small hole that's probably a reference point for an optical eye in the balancing device, and a screen tells the operator where to place the clip on the cage relative to the arrow.

We sell a ton of these annually (also fits 911 up to 1989) and don't get any complaints.

@UROpartsman

That is awesome. Thank you for chiming in and confirming that my asssumption was erroneous.

This blower motor assembly is looking like an even better, more viable option knowing the fan is balanced.

Out of curiosity, I'm looking for weight savings anywhere I can find them. Your blower motor housing looks to be injection molded plastic vs. the orignal cast pot metal frame.

I suspect the new DC motors are also lighter than stock.

Would you be so kind as to weight a unit? I just received a 2nd blower/housing to replace my housing that was all busted up. I'll weigh this stock one.

I would be be game to migrate to a new URO unit even if it only saves some weight of about 1/2 lb or so.

@UROpartsman
@superhawk996

Drew thanks for the information, i have a good stock one but we have been working on figuring out the resistor packs. I am going be ordering one of these soon for one of the fan housings that i am rebuilding. I see a lot of them on ebay i assume the are all the same? look the same , some sellers like partscontainer carry them and price varies slightly but not much. We will document the build and testing of the unit here as well if thats ok? as soon as i can get one in i will put it in unit #2 . fyi 914 rubber now makes that main seal that goes in the fan so a nice complete restoration can now be accoplished as long as that darn resistor pack is good!

Phil

No problem, the one in our photo weighs 556g / 1.226 lbs. How much does the OE weigh?



All of the URO brand units should be the same, don't believe we've made any running changes to these. These come in a plain brown box with a white and blue URO sticker, and a URO logo laser-marked as shown in the above photo. Documenting the build and testing would be fantastic, looking forward to it!

2.63 lbs

Just the pot metal motor frame alone (no motor at all, no impeller, etc.) weighs in at at a portly 1.46 lbs.

I can see a URO unit in the future!

Never realized that there were variations in the motor's and frames, but now looking back at Doc's photos, I see his motor and frame is different than what I had. Guess VW may have had multiple sources for supply chain reasons or maybe just migrated to more efficient materials later on.

@Drphil914
@UROpartsman

@Superhawk996
check it out- ebay listing of a fan motor like mine that has the metal surround not plastic,
i might get one- there are 4. Bosch motor.

https://www.ebay.com/itm/Front-Blower-Motor...4.m46890.l49292

This is what I was calling the blower housing frame, not so much the motor housing itself.

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This is the heavy part!

The other motor frame is also cast pot metal and is an open metal frame. The permanent magnets were glued into the blower housing frame. Completely different DC motor construction than the motor you linked, and/or which appears to be in both your pictures and was part of the 2nd used fresh air box I recived.

Blower housing frame on left, DC motor with open frame in center, pile of permanent magnets, spring clips, and fasteners on the right.

Click to view attachment

The newer type DC motor that are in the URO blower and that you linked to are way lighter than these parts.

Hard for me to put a vintage on these parts. My car is an early 73' but has backdated bumpers, early doors, and generally a mish mash of parts from who knows where. I suspect this is an early model based on motor construction, the inlet cowl seal, and the fact that it didn't have a plastic inlet grille but some homemade window screen!

@DrPhil914

well my new fan and motor assembly from URO arrived yesterday! so this will go in one of the fan housings that i have that will be rebuilt and sealed as soon as those parts arrive. I have one resistor pack that seems to be testing good , the other one i have to still figure out whats wrong with it before reassembly with the know stock oem fan and motor assembly, and the third one need a new motor so i ordered the brand new Bosch replacement motor to but into that fan, so 3 different ways to do this, depending on how deep you want to go, well even a 4th if you wanted to try and rebuild a motor but that does not appear to be possible on some of these according to how it looks from @Superhawy996 experiment turned out. he can confirm that, but the Fan/and motor assembly from URO is under $90. We just have to get the fan/housing seal, which 914rubber now makes, along with the flapper seals and seal for the lower fan to upper housing(diverter box).
Now if we could source a new or OEM NOS stock of resistor packs i could do a nice rebuild service with new seals, motor, fan and resistor pack.

Awesome Phil, keep us updated!

@Mikey914
@Superhawk996

for superhawk, update on my 2 fans with testing the resistor packs, with new leads and cleaning contacts etc i get same readings for both of these, low medium and high are at or close to normal range. I think both are good, so i will assemble each in a cleaned up housing with new seals, one will hvae my brand new fan from URO and the other will have the new used one that tests good from Al Merideth, good free turning fan i bench tested it yesterday.

But @Mikey914 no care package no seal or rebuild kit has arrived, this project is stopped until i get the seals from 914rubber.

Mark, i will buy 2 additional kits too with all the seals including the new big fan to housing seal and the flappers seals and lower to upper housing seals., along with hardware.

If you can have the staff email me a paypal invoice i would like this sent out asap. thanks,

Phil

@Mikey914

I have received a seal kit but wasn't able to get ahold of a seal for blower housing to the blower frame. Would really love to see you making these, that would allow for a total rebuild of foam seals.

Like @DrPhil914 . . . if you want to send me an invoice for a blower frame gasket, I'll glady pay to be the beta tester

@DrPhil914

If you're getting similar readings between Medium and High Speeds, I'm thinking that your DMM is having resolution issues at very low ohm readings.

Might be time to upgrade the DMM. I'm always a fan of Fluke but let's be honest, that is big money for a hobby meter.

I've used HF meters with good sucess - not pro grade but not bad for hobby use. I consider them to be "burner" DMM's. I prefer the newer AMES unit.

https://www.harborfreight.com/dm1010-profes...eter-64021.html

I also have one of these around and found it to be OK but is sometimes a bit glitchy if you just turn it on and fly right to ohms settings. It sort of locks up intermittently. If you switch on, wait and then go to ohms, it's fine.

https://www.harborfreight.com/5-in-1-digita...eter-98674.html

I was maybe going to recommend an old school analog Pro grade meter but OMG . . . prices have gone way up. Price is now comparable to cost for a Fluke DMM.

https://www.grainger.com/product/1A587?cm_m...ASABEgKdKvD_BwE

Gold Standard Fluke

https://www.mscdirect.com/browse/tnpla/5243...BSABEgLxmfD_BwE

thanks for the recommendations, i will invest in a good one, i had a much better meter but it took a crap last year , need a good one with a good warranty

Looks like I accidentally sent superhawk the care package
Please PM me your address and I can ship out tomorrow.
Mark

@Mikey914
@DrPhil914

oops -- I can also turn it around and ship to the Doc.

Go ahead and post up some pics. I will also be including some more new hardware you didn't know you need that were not included in the 1st package
Go ahead and keep it if you will use it.
Mark

@Mikey914
@Superhawk996

here is my first batch of hardware and seals from 914rubber!!
now the fun can begin- i will need a second set of stuff to do the other box, but i am going to install a brand new fan into one unit, and a known good oem one in the other.
both need all new seals and will have a nice clean and restored fan housing (lowered half) i need a replacement top half if anyone has a mint one please PM me it’s the late type with the screen, the air/ water diverter part.

tonight i will do one rebuild and post the pics of the during and after .
- first pic is of the fan seal no one makes until now! all the ones i have opened had these seals in very poor shape, it’s a porous seal not solid like the new 914rubber seal.
Thanks again Mark and Matt!

@Mikey914



You're killing me.

How do we get our hands on these goodies. Freshly plated omega clips would be outstanding. Same for the circular clips that hold the blower housing together. Blower frame to blower housing seal.

Not shown on website. Group buy?

yes he said there will be a group but soon, and should be listed both individually and as a kit soon, not sure of the timeframe but i’m sure he’ll chime in soon

i’ve had this apart for some time and finally had the time today to really clean it up and reassemble it now that the resistor pack has been verified as working. this one got the brand new URO motor and 914rubber seal and hardware.
also i cleaned it and decreased it , used a green scotch-brite pad and then polished with 5 step just like a paint correction, went from very dull to like new.
new flapper seals, the old ones were falling apart like dust . will ah e to drive the car this week to empty tank and then i can install the new fan box.

after polishing , overkill i know but might as well make it look as stood on the outside as on the inside. once i get to the point of installing it i will post again, i hAvr to change sour my controller and cables, which Mark also has and supplied with this kit.

the only thing i’ve not located that may keep some from restoring their box is new resistor assembly . in the end i found 2 boxes that had good ones. i have another box i will rebuild when i get new seals for it too, this one will go in my car , that one will be offered up for sale.

UPDATE:

finally got around to installing this new refurbished box, well not quite , i tested it first, and i only get one speed, same as before , and this is a new fan, resistor pack was tested for proper values, etc.
ok, first step i thought must be the controls, so i connected 2 other controllers that have cleaned contacts, and were tested before i bought them from the p.o. , same results.
the only explanation is that the wiring for the other 2 speeds is compromised, only the white/green wire allows for acompleted circuit once the slider attaches to that contact it is connected to. If i move the wire from the low to high connector then the fan will turn on but not on the other 2, so tonight i will experiment with a couple temp wires from the controls to the fan, i do think for some reason -
So the power goes from the fuse box to the fan and is hot from #8 fuse, and on with ignition. the circuit is completed when the lever is slid to right and the feeler contacts the selected connector and completes the circuit, low is just one wire, medium and high will have 2 feelers touching either #1&2 or #2&3. thus completing the circuit thru the different resistors , thru those and to the fan motor.

and one else ever have this senario?

tank up and box accessed- pretty clean under there.
box is out and i am not putting anything back until i have it figured out, and it’s tested . it may require in complete new wiring.

Don't think this is the issue with the fans, but the top picture shows a brown wire (usually a ground) that is just laying on the sheetmetal near the drivers side strut mount. You might look around for more loose wires and correctly attach them.

brown wire at bottom by the fuel pump is the ground for the pump,

The picture isn't that clear, was referring to the other end of the wire, can't tell if it is bolted to a ground point, or just dangling.

good eye, i had not yet moved that wire, it was the original ground wire for the pump, i had installed the tank 2 years ago after restoration , had everything in place and discovered that the ground wire to the pump had come loose, so rather than pull the tank to get at the ground i ran a different wire for ground by accessing the pump thru the small access hole in the bulk head where the pump mounts on a '75 car. but i will get this one properly re attached before putting the tank back now.

ok update from trouble shooting last night,
after getting into this and finding i still could only get one speed on the fan,
@Superhawk996 reached out to me and he suggested a few other things to check before moving forward, so i wanted to eliminate the medium and high speed wires as being the issue by testing them for continuity.
Right now i do have the low speed working, the white/green wire.
both the white(medium) and the white/yellow(high) both test same resistance, 2.8-3.0 ohms same as the one that does work , so that seems to eliminate the wires as the issue.
i also ran a long jumper wire from the controller/sliders on each of those ground connections so with a new wire i get same result. which also in another way rules out the
wires, and i have also hooked up 2 separate control mechanisms to rule that out and same issue there same result.

this leaves me thinking i am back to considering the resistor pack as the issue. now when i had the unit out for restoration and installation of the new fan and seals we tested the resistance of those and they seem to have passed the test being at the correct ohm readings but maybe not. so--- i am going to look for a second resistor pack , if anyone had one that has bench tested please let me know, but until then i have 2 choices, one is just leave this in like it is and deal with it- hey i have one speed, a new fan that does work, but not on all 3 speeds, its just frustrating i cant get this 100% working.

i am about to just say screw it. - i am probably saying this due to being up until 2:30 am this morning doing this and then trying to get the f-ing box back into place- now the mounting screw on left side stripped out. - way too tight on the seal fit- @Mikey914 this seal needs to be snug but not this tight, about 2mm less thick would help a lot in not having to use an f-ing crow bar to get the box squeezed up into place and bolted in......

Quick question and I don’t have a schematic in front of me to verify. But are the controls fully installed in the dash? And by that I mean is it bolted to the firewall using the 10mm bolt? It’s a bit foggy but I seem to recall only having one speed until I bolted the controls to the firewall.

yes, it is.

oh and after reviewing again the schematic and my pictures and referencing another source, Superhawk996 had me go back and compare and due to my plug housing being cracked and gone, the wire had been crossed and i am pretty sure that they are not on the correct pin locations on the fan housing SO.... when i get home these will be moved, but i will test the unit first by using aligator clip to a chassis ground and test each separate ground on the pins, taking the control unit out of the equation. will see how this test goes , along with just verifying i have a full 12v at the fan coming from the fuse board. if its not, i have other issues..

OK finally last night i was able to sort thru the wiring issues, figure out the proper positions for the fan wires, verified all the connections, the DAPO had list the plug housing and had not put them back in correct positions, with that corrected the new fan tested out and all 3 speeds work perfectly. before reinstalling i tested the other controllers and verified working along with my other 2 fans, those do work but not as well as brand new, so those will get rebuilt with new fans and hardware and seals. i will have 2 lower fan units that will be available and i can vouch for the resistor packs in both testing and bench tested and fully functional. this will be for sale soon if anyone needs one.
i struggled with one upper box unit that had a crack and was slightly warped, so the seal would not fit, that one had to be trashed, luckily i have a couple, 2 good ones so back together with new seals and clips.
i used Ian’s video suggestions of using rubber bands to hold the sucker in place when reinstalling the box. the seals are tight but my biggest issue was the warping of the top edge of the box.
the other issue with this is you have to pull the tank that’s a pain.
a few pointers:
1. don’t forget to put the connection for the fuel level sender back on before the expansion tank is reattached.

2. put the air duct hoses on before the tank and expansion tank because the passenger side is almost impossible to do otherwise.

3. new cable slide so nice and smooth, put them in , it’s worth the time.
- and the air box cable must be attached before box is installed .
installing thie box would be a lot easier if that cable were longer, due to its length it’s so tight it’s hard to angle the box or pull it out far enough to get the box at the right angle to slide it into place.
4. use a clamp like Ian did in his video or a pry bar for leverage to push the box up into place far enough to ge the box mount screws into place.

So i hope i don’t have to do this in this car again, but i am glad after 12 years i finally have a full functional defrost fan, and wiper mechanisms, and soon to be a new 911 motorized windshield washer pump conversion too. , while all this was open i added the wiring and the washer tubing, which no longer goes into the cabin. i installed a Carmagic switch into the column with my new levers i got from 914sixer. so that can be installed this week too!

Done!!

@Mike914 Mark thanks for making all the great parts and seals for the air box,
914rubber is the only company that makes the fan to housing seal, the big round one, and the vent seals and flapper seals!
these are now in their site for sale.

@UROpartsguy Drew, thanks for the info on the fans and making an affordable part! the fan is perfectly balanced.

this is how the wiring should be connected.
i am missing the plastic plug so it was all messed up

Doing some research. Looks like we can form these easy enough.
To get the correct wire seems to be the issue. I'd have to buy a coil of it and its not cheap.

A huge thank you to all the contributors of this thread! Currently attacking the blower restoration on my 6 and feel much more confident after reading this... 914 World rules.