Brose SMag motor leaking something?

skyhigh levo

New Member
Dec 12, 2020
32
10
california
Has anyone ever seen this before? You can only see it if you take the motor out of the bike.
There was a slight gap near the gasket. The two screws in the picture were loose and I was able to tighten them and see the gap close. Specialized claimed there was nothing inside to leak but after finding the kit I am pretty sure it was Vaseline.

Motor Cover Possible Leakage.JPG


Brose S belt kit.JPG
 

skyhigh levo

New Member
Dec 12, 2020
32
10
california
Specialized assured me it was the seat post or water. I offered to send them the picture but they declined. I did let them know the pictures were on this forum so hopefully they see it and respond.
Here is a picture looking up the frame at the bottom of the seat post, pretty sure its not leaking here.

Frame View with Motor removed.JPG
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
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I think you might be better asking @Bearing Man on here about the "leak" and also the kit you are searching for. The language used in the instructions suggest it was not professionally translated into English.............and I know of no automotive use of a toothed belt that requires treatment with vaseline!!
 

Bearing Man

Ebike Motor Centre
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Sep 29, 2018
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Has anyone ever seen this before? You can only see it if you take the motor out of the bike.
There was a slight gap near the gasket. The two screws in the picture were loose and I was able to tighten them and see the gap close. Specialized claimed there was nothing inside to leak but after finding the kit I am pretty sure it was Vaseline.

View attachment 47594

View attachment 47596
Wow! For a start I am way too cheap!! I include fitting it for that price. The belts are lubricated with Vaseline but once this has been done the Vaseline does not leak through the gasket, it generally stays put within the motor. Also if the Vaseline ever did make it through the gasket, it would coat the outside of the motor and anything it touched, so it's not Vaseline.

The screws used to hold this motor together are made from a very light alloy and must be very carefully tightened, they must be torqued and then stretched by turning a further set number of degrees. If the torx screws are just done up tight, if you return to them a few seconds later they are all loose again.
I have seen the S and T motor where water is coming through the gasket. This is a paper gasket and why the cases rot so badly under the gasket.

This issue is more noticeable if mud and dirt has collected around the motor inside the motor covers. This dirt stays wet and the motor then sits in a very wet environment for days on end, allowing water to soak into it.

In the case of Skyhighs bike, this looks to be just a case of loose screws. If the bike is outside of warranty, I would effeminately get it looked at to see how much water (if any) has entered the motor?
 

skyhigh levo

New Member
Dec 12, 2020
32
10
california
Thank you @Bearing Man for responding. I agree, the price is outrageous. I also originally though it was water in the gasket too, until I saw the instruction manual and the use of Vaseline on the belt. There is also a video on Youtube showing the procedure and they also used vaseline on the mating surfaces. So why the Vaseline? Only thing I can imagine is to reduce noise? I have 30+ years of experience working with industrial synchronous belt drives and lube on the belt is something new to me. I have access to engineers at Gates and will likely inquire about the Vaseline.
Do you know the specifics of the belt like who makes it and the part#? I have seen Brose cutaways before and the have used Gates in the past. I could probably get an honest answer if I knew the specifics.
 
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Mikerb

E*POWAH Elite World Champion
May 16, 2019
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Weymouth
Thank you @Bearing Man for responding. I agree, the price is outrageous. I also originally though it was water in the gasket too, until I saw the instruction manual and the use of Vaseline on the belt. There is also a video on Youtube showing the procedure and they also used vaseline on the mating surfaces. So why the Vaseline? Only thing I can imagine is to reduce noise? I have 30+ years of experience working with industrial synchronous belt drives and lube on the belt is something new to me. I have access to engineers at Gates and will likely inquire about the Vaseline.
Do you know the specifics of the belt like who makes it and the part#? I have seen Brose cutaways before and the have used Gates in the past. I could probably get an honest answer if I knew the specifics.
I agree. I have used toothed belts in a variety of engines...some of them high performance and never heard of using vaseline for anything in a motor/engine let alone on a belt. I cannot imagine it lasts very long given its very low temperature threshold.....it is after all primarily designed to be absorbed into warm skin!!
 

skyhigh levo

New Member
Dec 12, 2020
32
10
california
This motor is still under warranty, it was replaced under warranty about 6 months ago and now has about 1400 miles. First one only lasted 1100 miles.
I still think this is more that water. The only water this motor has ever seen is when I wash the bike, and then I only sprinkle it from above to rinse off the soap.
Should I try to get Specialized to replace it again? So far they will not listen to what I am telling them or even look at the picture!
 

Zimmerframe

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Jun 12, 2019
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Should I try to get Specialized to replace it again? So far they will not listen to what I am telling them or even look at the picture!
You're in the tricky position that many of us find ourselves in of being or being seen as suffering from motorcondria . Too man of us spend time worrying or over analysing if there's something wrong - rather than just riding or enjoying it. The same as we spend too much time trying to work out what financial inputs we can make to increase our performance on the bike.

Your first motor lasted 1100 miles, this one , so far 1400 miles. You have a suspected moisture problem - and loose bolts - which have survived 1400 miles of hard relentless mtb use.

It might go splat in 5 miles or might last another 6000 miles. Ultimately, you say it's still in warranty, so just ride it and enjoy it. If it breaks, get it fixed. I know the last time this took longer than hoped due to Covid, you can't predict what may or may not happen time scales wise, but you're making things harder on yourself trying to fix something which isn't broken - during covid life - which is going to be restricted in responses/response time.

Live the dream .. ride the crap out of it.
 

Bearing Man

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I agree. I have used toothed belts in a variety of engines...some of them high performance and never heard of using vaseline for anything in a motor/engine let alone on a belt. I cannot imagine it lasts very long given its very low temperature threshold.....it is after all primarily designed to be absorbed into warm skin!!
Same here. I really couldn't get my head around this one! All I can say is that without it, the belt is noisy and gets hot enough to start cracking.
 

Zimmerframe

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Jun 12, 2019
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This article talks about "belt dressing" .. intended for use on "rubber" belts (which isn't what you're using here) :


Everything I've read suggests you shouldn't use vaseline on epdm belts as it could dissolve them. Though the Gates belt is a mix of all sorts so could also be resistant to this. I would have thought silicone grease would be more appropriate ????
 

Bearing Man

Ebike Motor Centre
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Sep 29, 2018
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This article talks about "belt dressing" .. intended for use on "rubber" belts (which isn't what you're using here) :


Everything I've read suggests you shouldn't use vaseline on epdm belts as it could dissolve them. Though the Gates belt is a mix of all sorts so could also be resistant to this. I would have thought silicone grease would be more appropriate ????
Definitely no rubber in these belts, but it may also be used to stop or submit harmless contamination of other moving parts? Again, all I know is that it works for about 5,000 miles, then starts getting a bit dry. Slightly dodgy as the belt should be changed after 10,000 miles but if they don't strip or snap they seem to make it.
 

skyhigh levo

New Member
Dec 12, 2020
32
10
california
Where did you learn that it should be changed at 10,000? miles? Based on what you have seen do you agree with that or would you recommend changing it sooner? I know that any belt has an expected service life and I want to be prepared to replace it at some point instead of waiting until it fails completely. I can just imagine where all the shredded belt ends up and it cant be good.
I could hear the belt in my first motor slipping long before it failed completely. I will certainly have a belt kit on hand to use when my warranty is expired. I am sure I could complete the entire job in less than a day. It would be several days at best if I went to a dealer and they would likely only replace motor. Sending it to your service center in the USA would take even longer.
I found out the new belts are likely carbon fiber reinforced belts. It may be proprietary to Brose but if not my best guess at this point would be its a Gates MGT-608-21.
 

Bearing Man

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Where did you learn that it should be changed at 10,000? miles? Based on what you have seen do you agree with that or would you recommend changing it sooner? I know that any belt has an expected service life and I want to be prepared to replace it at some point instead of waiting until it fails completely. I can just imagine where all the shredded belt ends up and it cant be good.
I could hear the belt in my first motor slipping long before it failed completely. I will certainly have a belt kit on hand to use when my warranty is expired. I am sure I could complete the entire job in less than a day. It would be several days at best if I went to a dealer and they would likely only replace motor. Sending it to your service center in the USA would take even longer.
I found out the new belts are likely carbon fiber reinforced belts. It may be proprietary to Brose but if not my best guess at this point would be its a Gates MGT-608-21.

I guess you're talking to me?

I learnt it from Brose, this is from their motor manual: "Belt replacement and motor service General information and instructions Procedural description The customer wants to have a motor service and belt replacement performed Brose specifies a maintenance interval of 15,000 km for the e-bike drive Report service case via to Brose Service through trader" Although I only know of one or two motors that have made it this far yet,

Earlier belts (pre 2020) were a little unpredictable, lasting between a couple of hundred miles to 10,000 miles + Remember though, there is a massive difference between off road riding and normal road riding. A few pedal strikes will finish a belt real quick.

The belts don't slip and will not give any warning if they are about to strip or snap. Any slipping sensation is always the sprag clutch bearing failing.

Basically, it's a 5 minute job to change the belt once the motor is out, but you will need an ISIS crank puller, spider nut tool, bearing protector for spider puller, two legged puller, T25 torx bit, torque driver set to 0.2Nm and belt kit and a tub of Vaseline!

MGT-608-21 Gates Poly Chain synchronous belts are steel strand belts. The Brose belts are carbon fibre strand and made under licence for Brose (not available from the manufacturer).

Trust me, I have tried just about every belt out there in the early days. Steel core, aramid core, glass fibre, Kevlar etc. None worked for more than a few hundred miles, which is why I will only use the genuine belts now.
Anyway, hope this has answered some of your questions.
 

skyhigh levo

New Member
Dec 12, 2020
32
10
california
I guess you're talking to me?

I learnt it from Brose, this is from their motor manual: "Belt replacement and motor service General information and instructions Procedural description The customer wants to have a motor service and belt replacement performed Brose specifies a maintenance interval of 15,000 km for the e-bike drive Report service case via to Brose Service through trader" Although I only know of one or two motors that have made it this far yet,

Earlier belts (pre 2020) were a little unpredictable, lasting between a couple of hundred miles to 10,000 miles + Remember though, there is a massive difference between off road riding and normal road riding. A few pedal strikes will finish a belt real quick.

The belts don't slip and will not give any warning if they are about to strip or snap. Any slipping sensation is always the sprag clutch bearing failing.

Basically, it's a 5 minute job to change the belt once the motor is out, but you will need an ISIS crank puller, spider nut tool, bearing protector for spider puller, two legged puller, T25 torx bit, torque driver set to 0.2Nm and belt kit and a tub of Vaseline!

MGT-608-21 Gates Poly Chain synchronous belts are steel strand belts. The Brose belts are carbon fibre strand and made under licence for Brose (not available from the manufacturer).

Trust me, I have tried just about every belt out there in the early days. Steel core, aramid core, glass fibre, Kevlar etc. None worked for more than a few hundred miles, which is why I will only use the genuine belts now.
Anyway, hope this has answered some of your questions.
 

skyhigh levo

New Member
Dec 12, 2020
32
10
california
Yes, it was for you, I am somewhat new to forums and should have used reply. Thank you for taking the time to fully explain and share your knowledge.
I am pretty sure you are correct and it was actually my sprag clutch failing. I would hear the motor spin up every once in a while for just a second but wouldn't really notice the slip in the short time. It took about a month before the slip was noticeable and then not long until complete loss of assist.
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
6,568
5,058
Weymouth
@Bearing Man ....pleased you cleared up the misconception about belt slippage. I suppose it is possible with a toothed belt if the tensioner failed completely but that would be terminal in terms of drive. Re your comment on pedal strikes, I would add to that landing heavy on the pedals from a big jump but in both cases only if the motor was assisting at the time. That is less likely on a jump landing or a pedal strike on a descent.
 

Berto

New Member
Nov 16, 2022
6
0
USA. Ma.
@Bearing Man So vaseline it is.. Thanks bearing man , great info. Is there different kinds of vaseline, do not want to make a mistake .The vaseline thing is new to me. Just took apart my first s mag motor. Motor had no assist ,
belt was shredded, checked the bearings and “BOOM”!! Sprag bearing was broke. All the other bearings look good, would like to upgrade sprag bearings and extra seals and a belt. Can they be bought separately without the other bearings.
 
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Bearing Man

Ebike Motor Centre
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Sep 29, 2018
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UK
@Bearing Man So vaseline it is.. Thanks bearing man , great info. Is there different kinds of vaseline, do not want to make a mistake .The vaseline thing is new to me. Just took apart my first s mag motor. Motor had no assist ,
belt was shredded, checked the bearings and “BOOM”!! Sprag bearing was broke. All the other bearings look good, would like to upgrade sprag bearings and extra seals and a belt. Can they be bought separately without the other bearings.
Yes, it's called "Technical Vaseline" You can find out more here: www.ebikemotorcentre.com/product/technical vaseline
As for the bearings, see here: www.ebikemotorcentre.com/brose-bearings
 

Berto

New Member
Nov 16, 2022
6
0
USA. Ma.
@Bearing Man So vaseline it is.. Thanks bearing man , great info. Is there different kinds of vaseline, do not want to make a mistake .The vaseline thing is new to me. Just took apart my first s mag motor. Motor had no assist ,
belt was shredded, checked the bearings and “BOOM”!! Sprag bearing was broke. All the other bearings look good, would like to upgrade sprag bearings and extra seals and a belt. Can they be bought separately without the other bearings.
Yes, it's called "Technical Vaseline" You can find out more here: www.ebikemotorcentre.com/product/technical vaseline
As for the bearings, see here: www.ebikemotorcentre.com/brose-bearings
Thank you, will be placing an order. Is the polymer belt an option ? And the way to go? Did not see it.
this motor was given to me to fix, is there a way to bench test a motor? Thanks
 

Bearing Man

Ebike Motor Centre
Patreon
Sep 29, 2018
975
2,331
UK
Thank you, will be placing an order. Is the polymer belt an option ? And the way to go? Did not see it.
this motor was given to me to fix, is there a way to bench test a motor? Thanks
No, the current situation as I understand it... all new motors with prefix -200 are fitted with the Polymer belt. If this belt fails, it can only be replaced by the latest upgraded belt released at the start of 2022.
I can't guarantee these motor numbers or dates yet. Some motors have a carbon belt and some polymer and no one is saying anything so until we see a regular pattern, it is what it is.
 

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