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Discussion Starter · #1 ·
M5 Board....need some advise. Responding to this old post 1st....NOV 2021

Replacing gears for S85 throttle actuators.

Found two options. ONE looks great, but is binding when assembled (intermediate gear), the other is more expensive, looks cheep, and requires more work, but very common.

If I "Frankenstein" the two options, I use the gear/shaft combo from one and the intermediate gear from the other and get smooth actuation.

Anyone rebuild with either kit? pics attached.

NOTE: One pic showing a terribly damaged shaft gear....this pic was found on youtube.

Please advise,
P-Chi
 

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E60 M5 and building engines
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Discussion Starter · #2 ·
Hello M5 Board,

I have been researching rebuild kits for the throttle actuators on the S85 and sister S65.

Most of the information I am finding is out of date and/or inconclusive, so I have decided to start a new post.

I am currently rebuilding 2 "sets". I have found 2 different companies and both have pro/cons.

Also while researching have discovered: It not just the gears! Could be the motor or electronics!

Pics attached for now.

Doing a deep dive and would appreciate any knowledge that can be added to this post.

P-Chi
 

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I bought the Metal gear kit and mine also looked like it was sticking when moved by hand. I used a 12v source to spin the motor a bunch of times and added some antiseize and it started running smooth. I think it just needs to be broken in a bit. Put 500 miles on the car and no issues so far.
 

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Discussion Starter · #6 ·
This is the one I used. View attachment 956097
Hello Kaane,

Thank you for the updates and experience. When you tested/ran the motor, is is possible to do through the main connector or do you need to leave it open and go at the motor directly. I did bench test and run gears a few times but it requires reversing polarity when the set does not return to to "closed throttle". I did this first without the electronics cover. Then I stupidly tried to use the large terminals to control the motor through the connector at the large terminals. Aborted quickly as I was worried about the circuit board and potential damage.

NOTE: Also did add a full winding to the output shaft to get good return spring tension. IF this is not done, no hope for system to return to "idle". Also when "testing" found you can not "over wind" spring as it will no longer seat in the output shaft space provide.

M5 board/Team: Please keep posting and I will continue this post until I am very satisfied with the final rebuild.

Thank you!
P-Chi
 

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Both sets are similar in the pictures, but one with bronze and one with nickel intermediate gear plate, both seem lack of manufacturing precision, but if cycle them fix the binding issue then that is fine.
I would cycle them while installed few times until they start to get pack to Neutral position without binding. If they are installed the throttle rod spring them back to Neutral position, in this position also give them the proper voltage/current they require. To test them on bench may require more complicated setup.
I will report back when I test mine, I think I have the set that Kaane got in my shopping cart.
Good Luck.
 

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Discussion Starter · #8 ·
Hello platii,

Thank you for joining the post!

Did not think about it early, but will check for run-out on the intermediate gear to make sure they are concentric.

NOTE: Now thinking too much....have too sets of the metal gears and when installed (tried 3 of them) result was the same.

Will continue to dig!

P-Chi
 

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Well they may be the same manufacturer with different metal gear material.
Possible the lack of precision is in the manufacturing of the plastic gears, I didn't test myself to see where it is binding, when I do I will report back.
 

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Discussion Starter · #15 · (Edited)
Thanks again ALL for adding.

When I purchased the set, they mention "only works with 23 gear set"...found quote from my unnamed seller:

"Please make sure your original gear has 23 teeth (not 25 teeth) for this to be an exact fit before purchasing."

Now let's think about this: Main shaft/gear assembly provided by both second party companies are 25 teeth, same as all of my OEM shafts. The Intermediate gear is 51 on the drive side, same as OEM and other kit. The driven gear that mates to the Main shaft is also the same for this kit, OEM, and other kit at 13 teeth (the brass gear).

The spacing between shaft centers in fixed by the housing of the throttle body unit.

Did a 23 tooth shaft ever exist? PLEASE post if you find one. If yes must be VERY early generation. I have modules from 2006, 2007, and 2008 M.Y. and they are all 25 tooth.

Or is this an excuse to void any returns???? Certainly does not work easily on new units!

IF correct must be the brass gear at issue as swapping the intermediate gear with OEM or 2nd vendor results in the assembly working smooth! ODDLY, the metal gear kit replacement has 25 teeth...is the profile different? Gears are an engineering marvel!

Will continue to dig and have requested information from seller and hopefully contact with the manufacturer.

P-Chi
 

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Discussion Starter · #16 ·
Both sets are similar in the pictures, but one with bronze and one with nickel intermediate gear plate, both seem lack of manufacturing precision, but if cycle them fix the binding issue then that is fine.
I would cycle them while installed few times until they start to get pack to Neutral position without binding. If they are installed the throttle rod spring them back to Neutral position, in this position also give them the proper voltage/current they require. To test them on bench may require more complicated setup.
I will report back when I test mine, I think I have the set that Kaane got in my shopping cart.
Good Luck.
Same gears, different sides. See pic below.

P-Chi
 

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Discussion Starter · #17 ·
Latest research and mishaps:

Broke the "metal gear" output shaft gear when removing to install the BMW/OEM unit to test the "intermediate gear". In truth, I did medium Loctite the nut. Nut loosened, but gear broke when trying to remove completely. Does not condem this shaft.....still need more research.

Metal intermediate gear kit good from motor to intermediate gear driven. No binding!

Focus is now on the brass "drive gear" to the driven gear on the output shaft. And it FAILS. Both parts provided by "metal gear" company.

NOTE: Broke down the OEM unit to see how the "plastic gear set" would work. Glue not provided, but now understand why the use a metal dowel/cross-pin.

More to follow,

P-Chi
 

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Discussion Starter · #18 ·
FYI: For anyone removing the nut on the output shaft, I would recommend securing the output arm in a vice or other secure holding fixture, then remove the nut. This procedure will eliminate any stress on the gear backstop inside the unit.

P-Chi
 

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FYI: For anyone removing the nut on the output shaft, I would recommend securing the output arm in a vice or other secure holding fixture, then remove the nut. This procedure will eliminate any stress on the gear backstop inside the unit.

P-Chi
I used a vise on mine, just held it by the arm.
 
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