Caliper bolt sheared off....
Caliper bolt sheared off....
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beanbag

Original Poster:

7,346 posts

271 months

Monday 29th December 2014
quotequote all
On Christmas eve, I was heading over to the in-laws when I heard a knocking sound on my right rear wheel as I braked.

At the same time, I felt the braking performance of my car had reduced quite a bit so I pulled over to check out the problem but as it was dark, I couldn't see anything. I drove on as I was almost there and avoided using my brake as much as possible, relying on the engine to slow me down.

The following I had a look in the daylight and to my horror, I saw this: (Photo is upside down)



The caliper had completely fallen off on one side and was scraping against the inside of my wheel! I called up my mechanic who came over and found the bolt holding it in place had sheared off!! He managed to get the remains of the old one out and replaced it with a new bolt and the brake appears to be safe again but it's made me very nervous.

It also got me wondering. How common is this? And just the day before I was driving at speed. I dread to think what could have happened.

B'stard Child

31,151 posts

276 months

Monday 29th December 2014
quotequote all
When was the last time work was carried out to the brakes?

996TT02

3,342 posts

170 months

Monday 29th December 2014
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Probably overtorqued the last time the pads needed replacing. If you don't feel safe, you should have all bolts replaced and torqued correctly.

beanbag

Original Poster:

7,346 posts

271 months

Monday 29th December 2014
quotequote all
B'stard Child said:
When was the last time work was carried out to the brakes?
About 10 months prior to the bolt failing. I would imagine it's material failure rather than a bad installation as it's taken so long to fail.

B'stard Child

31,151 posts

276 months

Monday 29th December 2014
quotequote all
996TT02 said:
Probably overtorqued the last time the pads needed replacing. If you don't feel safe, you should have all bolts replaced and torqued correctly.
Most new bolts for brake calipers come ready coated with a thread lock material - if re-using new thread lock should be applied as they can come loose

And I agree - it's probably been weakened by overtightening

B'stard Child

31,151 posts

276 months

Monday 29th December 2014
quotequote all
beanbag said:
B'stard Child said:
When was the last time work was carried out to the brakes?
About 10 months prior to the bolt failing. I would imagine it's material failure rather than a bad installation as it's taken so long to fail.
No offence but bolts used correctly for the task intended don't routinely fail - at some time in the life of that bolt it will have been incorrectly fastened

If one has been overtightened then likely others were too - I'd replace them all (caliper fixing bolts) if I had an experience like that.

elliotff

174 posts

170 months

Monday 29th December 2014
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What car is this out of curiosity ?


beanbag

Original Poster:

7,346 posts

271 months

Monday 29th December 2014
quotequote all
It's a BMW E87 (1 series).

I've got the car booked in to have all the bolts checked. Still feel quite nervous driving it mind so I'm not pushing it at all until everything is sorted.

B'stard Child

31,151 posts

276 months

Monday 29th December 2014
quotequote all
beanbag said:
It's a BMW E87 (1 series).

I've got the car booked in to have all the bolts checked. Still feel quite nervous driving it mind so I'm not pushing it at all until everything is sorted.
Just ask them to replace - they aren't very expensive and whilst they can be checked for stretch by the time you've removed one to check you might as well put a new one in and get that torqued up to the correct setting with thread lock as appropriate

ikarl

4,064 posts

229 months

Monday 29th December 2014
quotequote all
I remember an old Sunny I was once changing the pads on, the offside was no problem at all, went round to the n/side and put the slightest amount of pressure on the ratchet and sheared the bolt clean off. Proper PITA fixing that., I was only changing the pads because I got a new set cheap, the ones that were on probably had another 5k on them!

PositronicRay

29,047 posts

213 months

Monday 29th December 2014
quotequote all
ikarl said:
I remember an old Sunny I was once changing the pads on, the offside was no problem at all, went round to the n/side and put the slightest amount of pressure on the ratchet and sheared the bolt clean off. Proper PITA fixing that., I was only changing the pads because I got a new set cheap, the ones that were on probably had another 5k on them!
Probably just as well, the pads may have lasted 5k but would the caliper bolts?

Krikkit

27,938 posts

211 months

Monday 29th December 2014
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I had a caliper slide pin on a Ford Focus round off the inside thread of the hub when removing for a brake pad change - a replacement hub assembly later the same thing happened! I'm guessing it was over-torqued during its life, as the spec was only 20-odd Nm I think. Low rather than f'ing tight!

Megaflow

11,586 posts

255 months

Monday 29th December 2014
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Speaking as an engineer, that wheel needs some careful assessment to judge how badly it has been damaged by the groove in it. If there is any doubt it needs replacing.

Hooli

32,278 posts

230 months

Monday 29th December 2014
quotequote all
ikarl said:
I remember an old Sunny I was once changing the pads on, the offside was no problem at all, went round to the n/side and put the slightest amount of pressure on the ratchet and sheared the bolt clean off. Proper PITA fixing that., I was only changing the pads because I got a new set cheap, the ones that were on probably had another 5k on them!
Had it recently on my bike too, I do most of the work myself so I hope it was down to one of the times they were bloody tight after getting done with an air gun on a tyre change.

ging84

9,548 posts

176 months

Monday 29th December 2014
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stop being nervous, these things happen, things brake on cars, very occasionally they'll have a major impact on where the car's heading, and very very occasionally that will result in something seriously bad happening.
you are many many times more likely to be involved in an accident because someone failed to look properly than any kind of mechanical fault, you can maybe half the chances by making sure it isn't you, but there isn't that much you can do about the other drivers



S0 What

3,358 posts

202 months

Monday 29th December 2014
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You get new bolts (if required) in with the new pads, if it came loose the new ones wernt fitted, if it sheared they (or rather it) were over tightened.

Sump

5,512 posts

197 months

Monday 29th December 2014
quotequote all
Megaflow said:
Speaking as an engineer, that wheel needs some careful assessment to judge how badly it has been damaged by the groove in it. If there is any doubt it needs replacing.
Speaking as a chartered engineer from MIT, I think he will be fine.

s p a c e m a n

12,124 posts

178 months

Monday 29th December 2014
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Phht, I used cableties through the bolt hole as a fix for that to get me home when I was young and indestructible. Don't worry about the brakes not working, worry about the top bolt shearing, grabbing the wheel and locking it up, throwing you into a tree biggrin

Konan

2,706 posts

176 months

Monday 29th December 2014
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The fun bit might well be getting the bit that's left in the thread out.

gazza285

11,217 posts

238 months

Monday 29th December 2014
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Konan said:
The fun bit might well be getting the bit that's left in the thread out.
beanbag said:
He managed to get the remains of the old one out...