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Refitting (an old) Hope Disc Brake Caliper...

parkinpantsparkinpants Posts: 53
edited August 2014 in MTB workshop & tech
Hi,

Having trouble refitting a disc brake caliper - it's a Hope M43 HBIS40. It's off an old Cannondale MTB (say 10 years old). I've attached a picture of the bike and also the bolts/washers/spacers.

So basically I made the rookie mistake of not remembering where all the bits went when I dismantled it. When I put it back on there is not just the noise of disc brake rub but all sorts of other clanging noises.

From what I can remember the shorter bolt was closest to the pedals, the longer bolt at the rear. The longer bolt had more washers/spacers.

Part C is marginally bigger (depth) than part D. Parts E and F are the same. G and H are odd one's out.

Looking at the picture of the bike (attached) there is just a washer (I think E and F) on the outside of the frame, leaving the rest of the washers/spacers to slot in on the inside of the frame but I don't know the correct arrangement/order.

Anyone help?

5wgrnq.jpg
2hgty52.jpg

Posts

  • nicklousenicklouse Posts: 81,520 Lives Here
    Looks like someone has been bodgeing. You should only need two bolts and a washer on each.

    So it kind of depends on what adaptor has been used.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • What adaptor are you referring to?

    There's a space in between the frame and the caliper on the inside, roughly the size of parts C and D, so that space needs to be filled (so I'll need more than the two washers E and F which were on the outside of the frame)
  • As for the bodgeing, the bike did have a fair bit of disc rub before that I couldn't fix despite truing the wheel, centreing the wheel, truing the rotor disc and aligning the caliper - so possibly the bodgeing explains why I couldn't correct it.
  • nicklousenicklouse Posts: 81,520 Lives Here
    Trueing the wheel will not cure disc rub.


    Ok basics.

    What number is on the caliper? What is the disc size?

    Have you ever had the frame disc mounts faced?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • The number on the caliper is M43 HBIS40

    Disc size, not sure, a lot bigger than modern ones. Do you want me to measure the diameter?

    I don't know what 'frame disc mounts faced' means but it was bought second hand - I 'might' be able to ask the previous owner about the history. Or I can take a close up of the caliper?
  • nicklousenicklouse Posts: 81,520 Lives Here
    There should be a number like 3 or 8 or 5 on the caliper. This designates the size of disc if is designed to work with. It also shows what adaptor should be used for a bigger disc ( yes disc size is needed). Like I implied in the first reply most of what you have shown is not needed.

    But without knowing the full story little useful advice can be provided.

    I am guessing the "adaptor" used has been a home made affair requiring all the other bits.

    Or some one bolt is just too long and the thicker washers are used to overcome this problem.

    If this is the issue just get the correct bolts. If not then I would look at the correct adaptor.

    I am guessing it is am M4 (looks like it) and it us a 3 caliper 165 front or 145 rear ( or 160/140)

    And HBIS40 is the hope +40 adaptor.

    Adaptor should bolt to frame directly. Caliper shoul bolt to adaptor directly.

    If the frame is not quite right you might have to use some thin washers between caliper and adaptor to align the caliper correctly on the disc.

    So no real what where but basic brake setup.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Okay...

    The caliper is M4, 3
    Rotor Disc Diameter is 20cm / 8"
    Adaptor is HBIS40

    I've take a picture of the rear setup and front by comparison. I note the front adaptor is not marked HBIS40, and has just a washer in between both adaptor and caliper.

    xlm9ow.jpg
    2cok9sj.jpg
  • bikaholicbikaholic Posts: 350
    This is an easy fix but requires a little bit of trial and error.

    Note that A (caliper mount bolt) is longer than B, so atleast one or two washers/spacers is required to account for the length otherwise A might protrude into the rotor.

    Here is how I would approach the problem:

    1) Hold the caliper over the rotor as it was working normally (with the rotor inbetween the pads);
    2) Account for the gap between the mount and the caliper using spacers and/or washers;
    3) If the front caliper sits too low then add washers/spacers underneath the Hope HBSM20H adaptor.

    Perform the bedding-in process afterwards.
  • I'm not sure what you mean by step 3 but, yes, the longer bolt does hit the caliper - so I'll put

    C and D on the inside of the frame (in the gaps between the caliper bracket and frame)
    E on one bolt outside of frame
    F on one bolt outside of frame
    G and H on the long bolt outside of frame

    2ywgxkz.jpg
  • CitizenLeeCitizenLee Posts: 2,227
    C, D and G look like they're from a BMX brake or cheap MTB rim brake.

    PM me your address and I'll send you some proper calliper bolts and washers! Got loads of spares so it's no trouble.
    Current:
    NukeProof Mega FR 2012
    Cube NuRoad 2018
    Previous:
    2015 Genesis CdF 10, 2014 Cube Hyde Race, 2012 NS Traffic, 2007 Specialized SX Trail, 2005 Specialized Demo 8
  • Nice one, will do, cheers pal.
  • CitizenLeeCitizenLee Posts: 2,227
    Nice one, will do, cheers pal.

    No probs, will pop them in the post tomorrow ;)
    Current:
    NukeProof Mega FR 2012
    Cube NuRoad 2018
    Previous:
    2015 Genesis CdF 10, 2014 Cube Hyde Race, 2012 NS Traffic, 2007 Specialized SX Trail, 2005 Specialized Demo 8
  • In the meantime I've set it up to where I think it was before 'the crash' (this is my mate's bike and his back wheel inexplicably came off yesterday - I'm guessing he didn't tighten it properly!)

    It's like this...
    C and D (spacers) on the inside of the frame (in between the caliper bracket and frame)
    E washer on one bolt outside of frame
    F washer on one bolt outside of frame
    G and H on the long bolt outside of frame - just to shorten it to stop it hitting the caliper

    I pushed back the pistons and the rotor disc then slots in nice and easy and spins with no noise or rub whatsoever (as you'd expect). When I pump on the brakes, and the pistons reset, it starts making a weird 'whirring noise'. I can understand that scraping noise you get against the pads with disc rub but this is something else. Any idea what this 'whirring noise' might be?
  • CitizenLeeCitizenLee Posts: 2,227
    Could still be a slightly out of true disk, not scraping but lightly touching. Spin the wheel and look inside between the pads, you'll be able to see any wobbles.
    Current:
    NukeProof Mega FR 2012
    Cube NuRoad 2018
    Previous:
    2015 Genesis CdF 10, 2014 Cube Hyde Race, 2012 NS Traffic, 2007 Specialized SX Trail, 2005 Specialized Demo 8
  • I had the wheel on the trueing stand and the rotor looked spot on to me. Here's a video of it so you can hear the noise I'm on about...

    https://www.youtube.com/watch?v=xW_eVhjXxbg
  • nicklousenicklouse Posts: 81,520 Lives Here
    So much noise from the freewheel who can tell.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • CitizenLeeCitizenLee Posts: 2,227
    I can hear the noise, but can't tell what it is other than it reminds me of when you'd jam a coke can in your wheel as a kid. Long shot but the tyre isn't rubbing the inside of a stay is it?
    Current:
    NukeProof Mega FR 2012
    Cube NuRoad 2018
    Previous:
    2015 Genesis CdF 10, 2014 Cube Hyde Race, 2012 NS Traffic, 2007 Specialized SX Trail, 2005 Specialized Demo 8
  • No, tyre is fine. It only makes the noise when the caliper is in. If I take off the caliper the noise disappears. Caliper didn't make the noise when pistons were pushed back, only after I pulled the levers a few times to reset the pistons.

    Ha, god coke can comparison. It reminded me of Crocodile Dundee 2 when Mick Dundee spins his whip at night time to scare the Columbian drug lords into thinking there's some sort of predator that comes out at night time.
  • HortonHorton Posts: 327
    The wheel is slowing down pretty quickly on that video unless your slowing it yourself... Makes me think either slightly sticky piston leaving one pad touching the disc rather than retracting properly. Only other thing I can think of is the little spring that slots between the pads may be bent/knackered and the end of one of the little prongs is hitting the disc causing that whirring.
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