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TMC/Bendix disc mounting bolt size

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Does anyone know the size (including the thread pitch and under head length) of the TMC/Bendix front brake disc mounting bolt (part number A089C8013F)? Thanks :)

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M10-1.25mm X 25

 

They have a recessed head with what appears to be an 11 or II marking.

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I just saw mine.. no idea what the II means...

 

Don't forget the lock washers!

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I just realized that on the X180-R /Sport 300, those bolts are different with the ABS ring being so close, they are a lower profile hex head.  FYI

 

Not sure what that means for the 91+ cars with ABS, looks like they all used the same bolt, regardless of ABS or no ABS.

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Yes, the Sport 300 is different bolt with a bobbin to spread the load in the aluminium mounting bell.

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yea, I made similar bobbins to spread the load on my Brembos (patterned after the X180-R).

 

IMG_4887.JPG

IMG_4886.JPG

 

Though the bobbins are hard to see on the X180-R/ Sport 300. 

 

P4170924.JPG

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I'm surprised the ABS ring is so close to the mounting bolts on the X180-R / Sport 300. I would not have thought that the Sport 300 mounting bell was much, if any, thicker than the TMC/Brembo disc mounting bell.

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Since it's aluminum, I guess they wanted to be a little conservative. I haven't seen the spacing to The normal SE hub ABS ring, wasn't sure if it was the same as the X180-R or not.

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I think the SE / S4 bolt and washer (it's just a plain washer) look like they would cause the the head of the bolt to sit higher than the ABS ring on the Sport 300 would allow. It's hard to tell from the photograph what the distance between the mounting bell and the back of the ABS ring is.

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on my car I am almost 100% certain those 4 bolts have lock washers!  Can't find any photos though, but my hubs are off the car for a bearing replacement this week, so I can double check.

 

I'm my photo of the X180-R hub, that distance is ~8mm.

 

Their rotor hat has a front thickness of 6mm, and then they back spaced it about another 6mm, apparently for rigidity?  Fitting a thick rotor like that on the Esprit (along with caliper clearance for 16" wheels) does give a pretty small window where the rotor can actually be.

 

In my setup, I had to set the rotor as close to the steering tie-rod end as possible, and that determined my rotor hat offset, just to give the caliper enough clearance in my 17" wheels.

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Ah, another 6 mm the other side of the mounting bell would explain the reduced distance between the ABS ring and the mounting bell. Do you know if the Sport 300 caliper mounting blocks were steel or aluminium?

 

BTW, I like the mounting bells you did for your conversion. I haven't seen the finished anodised product before.

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Thanks.  I didn't get them anodized until I was sure they would work, then did a batch with a friend.

 

The X180-R brackets are steel (I used 4140 chromoly)

 

Front X180-R bracket, you can see that the bolts all tap directly into the bracket, including the bolts that hold the aluminum hub carrier to the radius arm.  Which is the same thing that I did with mine.  You wouldn't tap aluminum like this of course.  

P4170921.JPG

DSC02586.jpg

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Hard to tell here, but there is maybe 2-3mm between the tie-rod and rotor.

 

IMG_3298.JPG

 

The 96-97 AWI V8 wheels give plenty of clearance, but the OZ Novas probably wouldn't...

IMG_3742.JPG

IMG_4894.JPG

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I think the SE / S4 bolt and washer (it's just a plain washer)

It's supposed to be a split ring lockwasher. The ones I checked the measurements on definitely were, just as I removed them from the car (1991 SE).

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I believe an aluminium adapter could work although I haven't done any calculations.  A high strength aluminium alloy such as Fortal has a yield strength higher than 4140 even though the tensile strength is lower.

 

If a spring washer is used I probably just cannot see the split on mine without disassembly :D

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Agree the aluminum could do it from a strength standpoint, but whenever you see an aluminum brake caliper bracket, it looks like they always do either a through hole, a pressed in bolt, an integral stud, and then a nut.  I don't believe anyone threads a bolt into the aluminum as the primary retention.  The thread strength in aluminum isn't great, especially on repeated removal, which is often the case with a fixed caliper, since you have to replace seals or rotors.

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Yep, a split spring washer is used.

I've gone with studs for the caliper adapter bracket (prototype shown).

Adapter_bracket.jpg

334 mm diameter discs are about the maximum that will fit in an S4 wheel with the caliper.

mzeNL3M.jpg

The dimensions you kindly provided were very helpful Travis, thanks again :)

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Glad to help.  Those look like the EBC RK series rotor?

 

What did you do on the rear?

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They are ATE 2 piece discs with cast in pins. Their aluminium hubs have been machined to suit the Lotus OE disc mounting with bobbins to suit the smaller diameter Lotus disc retaining bolts

 

I've gone with the late S4 onwards Brembo set up on the rear.

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