"Rounded-off" bolts

[magnuz]

Originally Posted by 960kg

Sometimes i wonder how unsafe the DIY mechanic is?.

It's not just the DIY mechanic, i've seen some pretty horrendous stuff done by main dealers !
I was recentely asked to look at a citroen because it smelled of petrol and had a new engine fitted by a main dealer. The fuel leak was because the fuel supply pipe connector to the fuel rail was a bit knackered instead of renewing it, they had secured it using a cable tie, there were also several important bolts around the engine bay that weren't tightened properly, as well as the clutch dragging !

Although i could have sorted it for them, i gave them a list of the problems & told them to get the main dealer to tow it back in, & if that they proved to be difficult,... just mention trading standard.

After a bit of hassle & fobbing off ..it was eventually sorted.

[canis]

Originally Posted by 960kg

When i had my `98 T4 and replaced pads i always took off the caliper to clean all the hard muck off i always had new bolts as they are "stretch" type and do have blue Locktite already on the threads. They are only supposed to be used once and torqued to the correct amount.

Hmm. You say you "always had new bolts", but they aren't supplied. So you'd have had to obtain them from the main dealership, I presume, as I've to date never found anyone who sells them. And I've been maintaining my own cars for over thirty years.

Are they actually stretch torque? I know they have a torque specification, and I know that some bolts are designed to stretch once and only once. I'm not convinced that's true of caliper bolts though.

I think you can take things a bit too seriously. I've driven hundreds of thousands of miles for decades and not a single caliper bolt has ever worked loose on me, in fact quite the opposite - they're always tough to get out. And I've not used loctite on any of them. Ever.

Then again, I also hear scare stories about brakes being soft for bedding in - which I am firmly convinced is a complete myth. I'm sorry, but I refuse to belive that brand new cars coming out of the factory with brand new discs and pads have inferior brakes which couldn't pass an MOT until they've "bedded in" - bollocks. Pure bollocks. No such phenomenon exists. When I fix my brakes, they work. Full stop. But I'm almost certain someone will come along with a "well, i knew a bloke once who" story soon enough.

[V40 Gaz]

Then again, I also hear scare stories about brakes being soft for bedding in - which I am firmly convinced is a complete myth. I'm sorry, but I refuse to belive that brand new cars coming out of the factory with brand new discs and pads have inferior brakes which couldn't pass an MOT until they've "bedded in" - bollocks. Pure bollocks. No such phenomenon exists. When I fix my brakes, they work. Full stop. But I'm almost certain someone will come along with a "well, i knew a bloke once who" story soon enough.[/QUOTE]

It's not that the brakes will have less performance, more that they will be easier to overheat under prolonged heavy braking.
A brand new disc isn't completely smooth, & a brand new pad isn't completely flat. Take a look at a new disc after it's done say, 30 miles, & you will see where the pad surface doesn't make contact yet.

[Nuddmann]

Originally Posted by canis

Hmm. You say you "always had new bolts", but they aren't supplied. So you'd have had to obtain them from the main dealership, I presume, as I've to date never found anyone who sells them. And I've been maintaining my own cars for over thirty years.

Are they actually stretch torque? I know they have a torque specification, and I know that some bolts are designed to stretch once and only once. I'm not convinced that's true of caliper bolts though.

I think you can take things a bit too seriously. I've driven hundreds of thousands of miles for decades and not a single caliper bolt has ever worked loose on me, in fact quite the opposite - they're always tough to get out. And I've not used loctite on any of them. Ever.

Then again, I also hear scare stories about brakes being soft for bedding in - which I am firmly convinced is a complete myth. I'm sorry, but I refuse to belive that brand new cars coming out of the factory with brand new discs and pads have inferior brakes which couldn't pass an MOT until they've "bedded in" - bollocks. Pure bollocks. No such phenomenon exists. When I fix my brakes, they work. Full stop. But I'm almost certain someone will come along with a "well, i knew a bloke once who" story soon enough.

To answer your question re calliper bolts, I'm a very occasional DIY mechanic and then only with adult supervision, I did my front brakes a couple of months ago and got a pack of bolts from my local dealer and I'm sure they were only about four or five quid if that. I phoned parts for volvos who told me the bolts are dealer only parts. Took a couple of days. That said, I've just ordered some pads and discs for the rear, Bosch ones, and there's what looks very much like two calliper bolts in the box with the pads. Look like they've got loctite on too. Trouble is two ain't enough so back to the dealer anyway!!

For the ease of ordering and fact they're going to be the right ones I'll order them before I do the rear brakes. Five quid over a couple of years is pretty cheap 😀 Wouldn't go main dealer for things like cam belt and water pump kit though, needed a sit down after asking how much that was!! About four times the cost of a Gates kit. 😱

[magnuz]

There seems to be some confusion in this thread between the larger caliper bracket/pad carrier mounting bolts & the smaller guide pin bolts.
The guide pin bolts are sometimes included with new pads, but the large caliper bracket bolts are most likely dealer only !

[patrick264]

Hi I havent done much diy on my car recently - but I did manage to get stuck caliper bolts off with Irwins extractors and also i found the volvo nuts and bolts quite inexpensive and agree these are once use only as far as I can tell, felt safer doing it this way .
Was quite pleased with my work.

[pookie]

Brian Pope in Stockport is the best place in the N.W. in my opinion. Walked in the other day and got a 3/8 whitworth bolt with an allen key drive off the shelf!
Set of Irwin sockets often solves the problem of rounded bolts.

Salut!

Pookie

[andy_d]

Originally Posted by 960kg

Sometimes i wonder how unsafe the DIY mechanic is?

When i had my `98 T4 and replaced pads i always took off the caliper to clean all the hard muck off i always had new bolts as they are "stretch" type and do have blue Locktite already on the threads. They are only supposed to be used once and torqued to the correct amount.

I always ever bought from Volvo as the aftermarket places only lead to bad practices. OK so a new plastic headlight can be aftermarket but not items on the car that demean it`s safety especially with the family on board.....

"dont know" plays a part
"but a bolt is a bolt" plays a part

boils down to the same thing,, people Dont know ,, or if they do dont care.

yes its a cost to use new stretch bolts each time and possibly the old bolts "might" be ok,, it might be ok to use some random bolt with a tensile strength of "unknown" ..

"best practice" + "Known safe" V cost / not knowing



,,,,,and peeps wonder Why when they get a new to them 2nd hand car they have issues and "OH" things to sort out to get it back to "known good and known safe"




personal pov
"don't know/don't care/don't care they don't know" is a major social issue that causes a metric fkton of problems for OTHERS ,,

[druid]

I got a set from eurocrapy parts for ?under £5?

[canis]

Who doesn't know? Actually, I do. I've just re-read the Haynes manual, these are NOT stretch bolts, they do NOT have a stretch torque, and renewel is NOT required unless they are "showing signs of obvious wear". The torque specification is unambiguously stated at 41 lb/ft for rear, 74 lb/ft for front, nothing else. Stretch torque specs would be something like wait 5 mins turn by 90°.

You presume my incompetence because it is you who doesn't know. You presume these bolts are stretch/single use because you don't know. The lack of citation confirms this.

These are not stretch bolts. They are standard automotive bolts, and providing sufficient grasp can be made upon them to deliver the specified torque, that is all they need. Confirmed both in print and in decades of personal experience.

And boom! Another myth busted. You're welcome.