Heli-Coiled Caliper - Query
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Heli-Coiled Caliper - Query
At work today I thought I would get paid and change my front discs at the same time
I did the near side no probs, as I've done them plenty of times. Then I got on to the off side, I undid the top bolt of the Brembo caliper no probs, but the bottom one was tight as hell. So I undid it bits at a time while spraying lube on it, so it didn't get too hot and snap etc.
Eventually the bolt came out, but it also brought the threads of the caliper out with it Luckily I could Heli-Coil it and get home. I also had to use a Stainless Steel bolt.......
Now, is it safe? The heli-coil was done correctly, but can I keep using it safely? I will change the stainless bolt as obviously stainless is brittle.
I did the near side no probs, as I've done them plenty of times. Then I got on to the off side, I undid the top bolt of the Brembo caliper no probs, but the bottom one was tight as hell. So I undid it bits at a time while spraying lube on it, so it didn't get too hot and snap etc.
Eventually the bolt came out, but it also brought the threads of the caliper out with it Luckily I could Heli-Coil it and get home. I also had to use a Stainless Steel bolt.......
Now, is it safe? The heli-coil was done correctly, but can I keep using it safely? I will change the stainless bolt as obviously stainless is brittle.
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Yes, helicoil is fine but replace SS bolt, I think OE bolt is 8.8 tensile strength. Stainless is softer than carbon steel at normal operating temps. Tighten to 75 ft-lb, manual says 113 ft-lb but this is excessive.
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Nice one, cheers guys I had to use a S/S bolt to get me away, as I was changing my discs at work when the threads stripped, and we only use stainless bolts (and everything) due to being a food factory. I have asked my mate to get me a bolt from his place of work
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I replaced the discs on the rear of my STi and one bolt just wouldn't come out, finally shearing. Luckily, I drilled out the remains and was able to clean the (a bit damaged) thread with an M10 tap. All went back ok but with less torque applied on that one!
I've heard of bolts sticking in these calipers!
JohnD
I've heard of bolts sticking in these calipers!
JohnD
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There are loads of people who have helicoiled or timeserted their Brembo's.
I think Brembo/FHI screwed up on this one, or at least cut some corners cost-wise.
Looks like FHI wanted a name brand caliper on the STI, as an upgrade.
These Brembo caliper bear the name, but are not up to real Brembo specs
Galvanic corrosion can easily occur, and the Alloy caliper is always going to come up short against a steel 8.8 bolt.
I think Brembo/FHI screwed up on this one, or at least cut some corners cost-wise.
Looks like FHI wanted a name brand caliper on the STI, as an upgrade.
These Brembo caliper bear the name, but are not up to real Brembo specs
Galvanic corrosion can easily occur, and the Alloy caliper is always going to come up short against a steel 8.8 bolt.
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In my case there was definitely a defective bolt (front caliper). It hadn't been machined properly and had a lump on the end of the thread but still got murdered in at the factory, obviously tore the alloy of the caliper to pieces when I forced it out.
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Mine were helicoiled when I bought them off a guy at Subaru. He states there was a problem with them being over-tightened at the factory.
With that in mind, I always thought it only happened on he first time the bolt has been removed, but the OP states he has done it loads of time.
With that in mind, I always thought it only happened on he first time the bolt has been removed, but the OP states he has done it loads of time.
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Might also be dissimilar metals causing a bit of corrosion making siezure more likely. I assemble caliper bolts with medium loctite thread lock (blue lipstick version available in Halfords). This is easy enough to undo when required and seals the threads against corrosion, never had any problems after using this stuff.
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Yes thanks, I thought I'd PM'd when they came. Sorry for not!
Glad the helicoil is nice and safe then does anyone have any high tensile M12x1.75 bolts I could have please? Well, not bolts, just bolt.
Cheers
Glad the helicoil is nice and safe then does anyone have any high tensile M12x1.75 bolts I could have please? Well, not bolts, just bolt.
Cheers
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LOL
dunx
P.S. Ev* Brembo bolts use a coarser thread and aren't prone to this problem... unless Godspeed tell you the wrong spec.
Last edited by dunx; 05 December 2010 at 08:53 PM.
#23
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Yeah Dunx if only I was as perfect as you I made a mistake once giving out the wrong thread pitch !
The Subaru has An M12 x 1.5mm pitch , and the EVO has an M12 x 1.75mm pitch on the front calipers.
Both cars rear calipers have M10 x 1.5mm threads though
It can be a problem with both cars calipers though , we get quite a few in to helicoil , we are set up to do either the mounting lug threads , or the inlet , pipe and nipple threads which are all M10 x 1mm threads
Cheers Ian
01656 723060
The Subaru has An M12 x 1.5mm pitch , and the EVO has an M12 x 1.75mm pitch on the front calipers.
Both cars rear calipers have M10 x 1.5mm threads though
It can be a problem with both cars calipers though , we get quite a few in to helicoil , we are set up to do either the mounting lug threads , or the inlet , pipe and nipple threads which are all M10 x 1mm threads
Cheers Ian
01656 723060
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You may aspire to my lofty heights...
dunx
P.S. My tame MOT tester builds loads of big BHP Ev*s and he's done about two in the last three years... but lost count on Subaru failures.
dunx
P.S. My tame MOT tester builds loads of big BHP Ev*s and he's done about two in the last three years... but lost count on Subaru failures.
Last edited by dunx; 06 December 2010 at 01:09 PM.
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