How to remove front brake caliper housing bolts! (Gen 1)

Thought I'd share following for benefit of Tuoldo owners:

I bought some stainless steel replacements, but was warned the original bolts are made of cheese, and the Allen key heads round out easily. They are and they do!

But if the right technique is used, there shouldn't be a problem.

So...

• Do clean out any crud from the Allen head bolt first.
• Do use a hardend Allen key bit, with a suitable socket ratchet. (Mild steel Allen keys, hammered, etc, will just bend!)
• Do tap Allen key socket into bolt head to ensure fully installed. Failure to clean and tap key into bolt head will round out the hole at the first attempt!
• DON'T put gradually increasing pressure on the wratchet handle... or you will be sure to round out the Allen key head!!!
• DO put steady pressure on the wrench handle then repetitively bounce the handle down to put 'sudden' extra load on the bolt, to help break the corrosion/crud which will be fouling the thread. (NB: This is simple application of the laws of inertia)

I found the above worked fine on my bolts.

Above, and beyond these fundamental keypoints, you can also do the following to help:

- Spray WD40 (etc) on end of bolts, on inside edge of calliper (avoiding over spray into disk!!!). Leave it to penetrate for 10+ mins.
- Put Allen key socket into bolt head and give 3 or 4 sharp taps with a pin hammer, etc.
- Gently heat caliper around bolt head with paint striper gun (avoiding excess heat to prevent paint damage).
...And ideally spray freezer spray on bolt head before applying ratchet procedure above.

But... if that fails and Allen head bolts round out, it's probably best to drill bolt head off (one at a time, and replace bolt before doing the next), then drill smaller pilot hole into stud and applying a stud extractor. If you try this without drilling bolt head off, the stud extractor will snap off... making the problem worst!!

I'm told, if you drill off all bolt heads, then take caliper apart, the studs are easily removed with a pair of mole grips, but then you need to clean caliper and will get brake fluid leakage, etc.

Hope that helps someone!

PS: Don't ask me how I learned the above!

Paul D said:

- Gently heat caliper around bolt head with paint striper gun (avoiding excess heat to prevent paint damage).
...And ideally spray freezer spray on bolt head before applying ratchet procedure above.

Click to expand...

On reflection, if deemed necessary... better to gently heat the bolt head, with a blow torch (avoiding burning paint), and if freezer spray available cool caliper housing. The idea is the bolt expands length wise, which reduced the torque needed to loosen it. Appreciate it has to get pretty hot to do this, but every little will help! It is a well known technique used to dismantle engines, etc, but usually bolt head needs to be red hot, which isn't viable with a painted aluminium caliper body. Anyway, trust the technique might come in useful for other reasons too!

If the brake housings are ally be careful with steel bolts as mixing metal can cause galvanic corrosion. I was had a fireblade with ally sump and steel sump bolt that ended up suffering galvanic corrosion

TK, I think that is exactly the reason why the original caliper bolts are hard to remove (compounded by alloy heads rounding easily in the soft steel bolts ). All the bolts I removed had a white alloy oxide crud compound, due to corrosion between the dissimilar metals (alloy vs steel). The trick is to use copper grease on the thread (ONLY) when replacing the bolts with S/S units. Avoid getting it on the underside of the bolt head though, to stop the bolts vibrating loose, or risk of striping alloy caliper threads when torqueing up.

used bikes can be a pain, copper grease most of my bolts on my new bikes, so the next owner will get the benefits

good tip i found, before doing the bolts up, put the calipers on the disks, pump the brake a few times, hold the lever and tighten the bolts, helps to centralize the pads and stops the pads rubbing!

Scream,shout jump up and down throw things around garage/shed kick the bike/dog/misses then do what you said lol ps not a prob on a factory