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So I have finally got round to fitting some Clark hydraulic brakes to Mrs G's old Hardrock, the bike that won't die. The brakes seem to work absolutely fine and at £50 for a full set, feel like a bargain.
However, I am having trouble aligning the rear. As you tighten the brake caliper up, it pulls to one side (so away from a vertical alignment) and this makes the disc rub. Limited research completed, but it looks like I need to try and fit some cup and cone washers. Does that sound the right way to go? Looking at the brake, the surfaces don't look perfectly flat (but this may just be me imaging this).
I have some brakes (Shimano) that came with these cup and cone washers, others (Hope and this aforementioned set of Clarks) didn't.
Maybe got the frame surface faced at an lbs then just use std brake shim washers
I need to try and fit some cup and cone washers. Does that sound the right way to go?
That will space the caliper out so it won't match the rotor. This is a pretty standard problem. You need to check the mounting faces and scrape off any paint. Sometimes you just need to give everything a very light rub with a file to take off any burrs. Also, check the bolts and washers to make sure they're all in good nick. Leave the bolts slightly loose when you fit the brakes, then clamp the brakes on hard and carefully tight the bolts properly.
Pull the brakes on as you tighten the bolts as said above.
Thanks Fossy and Hols2. I've tried the loose, apply brake and then tighten up method, but with no joy (although it usually works a treat for me).
Weirdly the mounting faces look ok (on the frame), but the brake caliper really leans to one side when you tighten it up; I have tried with a different IS to post mount adapter and it is the same thing, so I don't think it is the adapter Clarks supplied with the brakes causing the issue. So to me, it looks like the caliper itself does not sit flat on the adapter (if that makes sense)? Bolts are all new.
I'll see if I can rub down the faces of the bits that meet up.
Have you tried holding the caliper in place and gradually tightening the bolts so you can make sure it isn't moving?
Hi mashr - yes. It effectively rolls off the vertical as you tighten it up (you can see it quite clearly as you tighten it); I've tried several times, thinking I must be doing something wrong.
Hayes do an alignment tool that often makes it a bit easier.
It effectively rolls off the vertical as you tighten it up
The mounts aren't parallel/perpendicular. If you can see where the problem is, careful tidying up with a file should fix it. With the old ISO mounts, it's often just paint throwing things off.
If the top of the caliper is not perfectly flat then conical washers above the caliper will help but you might need slighgly longer bolts, also Clark's adapters aren't great, there can be gaps when the caliper rests on the adapter, CNC'd ones are more precise.
The paint on the caliper is probably uneven so a bit of a sand down with fine wet n dry could help.
What you're describing sound like theres a slight slope on the caliper so conical washers under the bolt head seem the best option.