Broken bolts on Bosch CX motor

[Jona]

Hi,
I have already replaced 2 bolt on one side. And now the over side one bolt broke also. Anyone else who had the same issue?

 

[Jona]

I have found this Broken Bosch motor mount bolts!

 

[Jona]

If anyone would ever have this problem. This is how I solved it.
I bought left taps (ez out) to remove the broken bolt.

I replaced with stronger screws. Tensile strength of 10.9. zinc plated. Because stainless could cause contact corrosion with magnesium case. The screw bits are 5 point torx (ts) with hole.

 

[scjgreen]

If anyone would ever have this problem. This is how I solved it.
I bought left taps (ez out) to remove the broken bolt.
View attachment 50725
View attachment 50726
View attachment 50724
I replaced with stronger screws. Tensile strength of 10.9. zinc plated. Because stainless could cause contact corrosion with magnesium case. The screw bits are 5 point torx (ts) with hole.

I have the same issue Jona. How have you found the fix? Have you have any more Broken Bolts?

 

[Jona]

I was able to fix it with the tools mentioned above. I haven't broken any more bolts.

 

[Marquez93]

I have the Bosch CX in my 2020 Focus Jam2, just had to drop the motor to access the connectors.
The mounting bolts are very soft, where can I get decent replacements?
Cheers

 

[scjgreen]

M5 x 10mm Socket Button Flange Screw BZP Grade 10.9

Bright Zinc Plated Socket Button Flange Screw M5 x 10mmHigh-tensile bright zinc plated steel screws with a flanged button head. The flanged button head design spreads tension over a wider surface area and acts like a washer by reducing the impact on the surface below. The bright zinc passivation...

www.fusionfixings.co.uk

 

[Marquez93]

Unfortunately my bolts are 7.5mm threads, according to my vernier gauge, so the M5s won't do it for me

 

[Muff1tt]

Just offering a tip for anyone to prevent rounding the bolts off as I've done this myself. The bolts use a torx plus bit to remove not a standard torx bit. They are very similar but the fit of a torx plus is much better.

 

[Wilbur]

Just offering a tip for anyone to prevent rounding the bolts off as I've done this myself. The bolts use a torx plus bit to remove not a standard torx bit. They are very similar but the fit of a torx plus is much better.

Which fasteners are you referring to? The motor bracket screws are not torx plus; they are 5pt pentalobe security bit size 25.

 

[Muff1tt]

Which fasteners are you referring to? The motor bracket screws are not torx plus; they are 5pt pentalobe security bit size 25.

The main motor bolts that attach the frame to the motor brackets

 

[Wilbur]

Which are not being discussed in this thread...

 

[Bones]

I replaced mine with stainless Allen bolts. Only because I had them handy and I used a standard torx to remove the original bolts.

 

[Wilbur]

I replaced mine with stainless Allen bolts. Only because I had them handy and I used a standard torx to remove the original bolts.

And now everyone is confused

 

[Bones]

And now everyone is confused

Sorry I been on the beer

 

[Stihldog]

If anyone would ever have this problem. This is how I solved it.
I bought left taps (ez out) to remove the broken bolt.
View attachment 50725
View attachment 50726
View attachment 50724
I replaced with stronger screws. Tensile strength of 10.9. zinc plated. Because stainless could cause contact corrosion with magnesium case. The screw bits are 5 point torx (ts) with hole.

What size drill bit did you use for the pilot hole? Did you use the smallest EzE-out? I believe I have the same size eze-out kit. Did you use a drill press and centre the drill bit or a hand drill?

This seems like a delicate process, but I really have nothing to loose.

 

[Wilbur]

Two broken screws Stihldog? I'd start with the smallest EZE-Out; can always go bigger. What screws are you going to replace them with?

 

[Stihldog]

Two broken screws Stihldog? I'd start with the smallest EZE-Out; can always go bigger. What screws are you going to replace them with?

I’m not sure yet. Hopefully I don’t do anymore damage when I remove the broken bolts. The holes in the bracket may be out-of-round also ().

IMO the bracket may not have been torqued correctly which caused a slight movement until the bolts sheared off. This is my neighbours motor so I can’t attest to the movement before the bolts failed. Regardless, this motor is in perfect condition …other than the broken bolts. I’ll try to remove the broken bolts before I decide on replacement bolts.
Any ideas?

 

[BIG-DUKE-6]

I would go with grade 8 bolts if you can find them. Stainless is too soft .

 

[Wilbur]

You can get grade 12.9 alloy steel flanged cap screws, optionally with serrated flanges for extra grip.

Rail (625Wh) - you may want to watch this #TREKRAIL

So I've done a little research on replacement M5 screws for Gen 1-3 Bosch motors. The originals are black M5 x 16mm flanged security head (T25 5-pt pentalobe). The 11mm flange is not serrated. The head is ~3mm tall. They don't appear to be thread-forming as the tip isn't blunt-tapered, (even so...

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