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What is the list and order of components that thread onto the Brompton's rear brake assembly from the brake caliper through to the Lower Stop Disc for an M6R?

At some point on a recent ride down through the Himalayas my Lower Stop Disc fell off, and I lost many other components that belong on the rear brake caliper bolt as well (ie: washers, nuts, concave washers fit to the frame, etc).

There’s no Brompton dealer in this country, so I need to buy the replacement parts online. But how do I know what I’m missing? There doesn’t appear to be any schematic that shows all the components that thread onto this rear brake bolt. If I had a list and image of these components, then I could figure out what I don’t have, order the parts, re-assemble the parts, and be on my way. But the only relevant schematic I could find for the LSD only shows the components of the LSD itself--not the components in context found on the brake caliper bolt on which it threads

Can someone with an M6R please take some close-up photos of their rear brake that captures all the components that thread onto the rear brake caliper bolt that passes through the rear rack and ends with the Lower Stop Disc? Photos of it disassembled with the components lying exploded & in-order would be excellent too

Thank you

Brake Caliper bolt's components after LSD fell off 1

Brake Caliper bolt's components after LSD fell off 2

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  • 2
    You should post either the model year or a photo of your front brakes as the Brompton brakes have undergone a number of revisions
    – RoboKaren
    Commented Aug 19, 2019 at 2:33

3 Answers 3

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I cannot comment to the previous answer so I will write a new one. The order specified in the previous post is different compared to what the data sheet says.

The order of components for the brake caliper assembly are documented in the datasheet ds-brcal issue S1062. Unfortunately it is not seem to be publicly available on https://trade.brompton.com. However, an online search can reveal the documents on other sites [1] [2].

  1. Rear brake caliper
  2. M6 washer
  3. Carrier platform bracker (rear rack)
  4. Mudguard bracket
  5. Concave washer
  6. Hole in rear frame
  7. Concave washer
  8. M6 washer
  9. Spring washer
  10. Lower stop disc assembly (including nut)
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I was successfully able to repair this loss. It required the following items that fell off the brompton rear brake bolt:

  1. 2x concave washers
  2. 1x spring washer
  3. 1x M6 flat washer
  4. 1x Brompton Rear Brake Nut (RBNUT), including a flat washer and nut

Note that I have a 2016 M6R Berry Crush Brompton Black Edition. The LSD on this bicycle is the Mk3 variety, as distinct from the Mk2 type.

The Mk3 LSD Kit from Brompton (QLSDA) included the RBNUT and its flat washer & nut. It also included one concave washer, a spring washer, and a flat washer. Note that the kit did not include the second concave washer; I had to get this separately (I don’t think there’s a part number for this; I just asked the bicycle shop to send me one, and I was lucky enough that they had a spare lying around).

The complimentary schematic to the LSD schematic linked-to in the OP which actually explains the context of what fits onto the rear brake bolt (including the LSD and everything before it) is actually the schematic for the "rear carrier" aka the rear rack.

To quote the relevant section from the above document:

feed the brake bolt through:- the M6 washer, the forward bracket on the carrier, the mudguard bracket MGB, a concave washer, the bridge tube on the rear frame, a second concave washer, the spring washer, a second M6 washer, and screw on the rear brake nut RBNUT (with the LSD attached) by two or three turns. Make sure that the forward end of the mudguard lies forward/above the cross tube between the chainstays...Partially tighten the RBNUT. Do not fully tighten this nut at this stage...Set the LSD as described below… The lock-nut should be slackened off. Fold the bike completely, and spin the LSD along the thread to give the correct gap of 1-2mm. Finally, using 2 spanners, 19 AF and 15 AF, tighten the lock-nut: do not overtighten, correct torque 8NM.

Therefore, the order of install on the rear brake bolt is:

  1. Rear Brake Caliper & Nut
  2. M6 Flat Washer
  3. The forward bracket on the carrier (rear rack)
  4. The MudGuard Bracket (MGB)
  5. A concave washer
  6. The bridge tube on the rear frame of the brompton
  7. A second concave washer
  8. A spring washer
  9. A second M6 flat washer
  10. The Brompton Rear Brake NUT (RBNUT) onto which a nut, washer, and LSD are threaded

Please see the photos of the assembly for further reference

enter image description here enter image description here enter image description here enter image description here enter image description here

You can also view a this video, which shows how to install the components in-order when installing the rear rack.

Watch the video showing how to install the rear rack
Watch the video showing how to install the rear rack

Thanks to Rachel, Derek, Jack, and all the fine folks at Edinburgh Bicycle Cooperative for helping me piece these proprietary components back together again!

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The manual shows the washer & spring washer the other way round. Don't think it'll make a major difference, just saying... http://www.thebromptonman.com/uploads/2/8/8/6/2886356/ds-brcal.pdf

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