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Stripped rear brake master cylidner mounting bolts!!

4119 Views 41 Replies 11 Participants Last post by  Veefer97
I have an 06 gixxer k6 and I stripped the shit out of these bolts trying to get them off:

They're only supposed to be torqued to 7 ft-lb per the service manual. But with their thread lock and the fact that they haven't been touched since mfg of this motorcycle they're practically welded in there.

They have a 4mm hex head which is tiny and didn't stand a chance with the force to get these off. I rounded the hole and the hex grip is gone.

Now I dremeled a nice slit to fit a flathead screw driver, but these fuckers won't budge. The flathead is stripping the slit and I can't get any leverage. They're mangled now and I think it's time for a screw extraction.

So 3 questions:

1) Does anyone have the size spec of these screw threads (width, length & thread)? Specifically the width so I know what size extractor bit to use.

2) Do you agree that it's time for a screw extract? What product is best and where to buy? EZ out? Home Depot? Auto store?

3) Extra opinions on this matter

:comp FUUUUUUUUUCK! :comp
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Those mushroom bolts are what this thread is about.

I didn't want to remove the brake hose and the rearset because then I have to deal with messy brake fluid and recharging the line. I guess if I got the whole rearset off it would be easier to work with on a work bench and with vices. But again, I'm trying to prevent disassembly of the braking circuit.

In anycase, I'm afraid to to use a screw extractor cause they say if it breaks off in there, you're fucked. And when I tell you guys this screw is practically cemented in there, I shit you not. With the thread lock on it, it probably needs over 15 lb-ft of torque to remove which is absurd for the size of that screw.

Has anyone else had problems with these 2 specific screws on the gixxer? I'm wondering how anyone would've gotten them off without incident (even a mega professional) - what could've been done?

I guess the problem was just assuming they would come off - so I didn't take any precautions before just trying to loosen them with a 4mm hex. Going forward, what precautions should you take before trying to loosen a small hex screw that has heavy thread lock on it?
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Oh oh...I see what you're saying Scratch33. If the mushroom heads come off, the master cylinder will dislodge from the rearset and I can finish the rest of the job on a workbench. I don't know why I misread that. In anycase, see above - I'd like to avoid brake circuit disassembly.

What I'm doing here is swapping out the rearsets (stock for Vortex). I thought I could get away with removing those 2 bolts, swapping the stock rearset for the Vortex one, then reattaching that master cylinder without disrupting the fluid circuit.

But I know I know...beggers can't be choosers - lay it on me.
I knocked it out of the park with using a chisel as a screwdriver. When I put the chisel in the dremeled slit, it had plenty of leverage. It still took getting red in the face for the screw to loosen.

Nevertheless, here's the end result:

It took so much torque I damaged my chisel as you can see.

What the fuck is Suzuki doing putting red thread lock on these bolts??? Christ.

+1 on the impact driver suggestion for this to never happen again. I knew I was being an amateur somehow. I'll look into getting one ASAP. +2 on the chisel suggestions - I was thinking of getting an extra wide flat head screw driver (if they made them) and they's called a chisel!!! :dblthumb

I measured the bolt and it's 20mm x 5mm for anyone who cares. And the head, before it was ass raped, was a 4mm hex.

Thanks to all - you guys really helped! I'm totally relieved! Time to finish that rearset job. I'll post pics when I'm done.

Miller time! :beer
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It's like an orange. I read about it on other forums. It's from Suzuki (not loctite) so it's probably not loctite red now that I think about it.

Nevertheless it felt like loctite WELD.

Back to impact drivers, what's their success rate? Do they damage the bolt even if they get it off? From what I saw on these bolts, I don't see how anything could've gotten it off and kept them in mint condition.

When I google impact drivers, there's plenty of info, but no real good illustrations of how they work - I'm not really understanding it. And some things say they're good for phillips head bolts but not so much on any other kind. Where are the facts?
So does this destroy your bolts or deem them useless for reuse?
So should you ALWAYS use an impact driver when removing bolts? Or should it be avoided if you think you can get the bolt out normally?

All I'm looking for is to never strip a bolt head ever again. I'd take destroying a bolt and buying a new one cause they're so cheap - over having to do an "extraction" process. It's way too inconvenient. And bolts strip WAY too easily.

It's also the stupid cheap mushroom head OEM small bolts. They're so cheap. There's such better construction for bolt heads for bolts that small. I hate suzuki's OEM mushroom bolts.
I was in HD the today grabbing some stuff and I decided to look at impact drivers. They don't have any manual ones. But they have a bunch of electric ones for unreasonable prices (except that cheap ass Ryobi one).

Are these electric ones even useful? Or the manual one is by far better?

So where are you guaranteed to find a manual one?
I see a manual one at Autozone. Home Depot doesn't have manual ones. The manual at Autozone is $9.99.

The power ones are over $200. I'd like to be a big spender Veefer, but I'm just another American pauper in a country that's going down the tubes. All I have left is my gixxer with 2 broken bolts :lol

Winner...manual impact driver!!

Explain to me why I would need to spend over $200 for an automatic one?
Thanks Veefer. You've always been so helpful on all my posts.

So I picked up that manual impact driver and I get it now. It's totally badass. I got a pair of bolts off the bike with it. It barely moves them. It just nudges them enough to break the thread lock seal.

Just a few questions. With the mallet, should I be hitting the driver hard and 1 shot at a time? Or a bunch of quick taps while turning the driver left?
You know, I agree with you sport-ryder. The medium and light duty bolts on these bikes suck so much. I really only feel comfortable reusing the higher quality bolts with deep & large allens and square drives. You can tell a quality reusable bolt just by looking at it.

The light duty ones, like the ones I stripped (4mm allen heads) look like you can almost chew them like bubblegum. Obviously it held like a motherfucker, but the head is so soft and cheap, I feel like it's counter productive to have something hold so tight with such a fragile head.

The replacements for these bolts is under $2 from Suzuki (which is overpriced OEM) - so that's how cheap they are. I would almost be inclined to get replacements from hardware stores like you mentioned with better drives.

The only problem I have with hardware stores here in the states is that they have more SAE bolts than metric. So you don't have a lot of variety on the metric side of things. Damn founding fathers SCREWED us (no pun intended) :lol
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