Rounded Bolt

qballirl

I have just tried to change the brake pads on my Car but it seems the bolt for the caliper is rounded, it takes a 7mm alen key and cant get it off can any one advise what to do here.

Ive heard some where that hammering a larger key in to the bolt is the standard procedure but its in an awkward position and dont wanna do it without prior knowledge.

bbam

Ouch..
If you dont have experinece with this kind of repair I wouldnt advise it.. You might bring this one to a mechanic.. Once its sorted you will be back on track for your own maintenance..
Cheers..
bam

bucks

Have you got the wheel turned to get proper access ? (make sure you are using an axel stand and not only a car jack)

Can you see enough of the bolt to get a vice grip on it ? if so try that first after giving it a good dose of WD40..

Failing that there is a special socket that you tap on with a hammer and it grips the head of the rounded off bolt. Then you use a ratchet to take it off.

Another option would be a case of welding a bolt onto the end of it and getting it off that way.

It will probably work out cheaper if you just bring it to a mechanic instead though.

qballirl

Yeah ive done all the following turned wheel in using axel stands, sprayed wd40 will probably spray it again tomorrow to let it eat through just afraid that if i have to weld something on to it or damage it any further ill have to replace the whole caliper rod and im not sure what the rest of the bolts are like on it so they could be the same, as well the brakes are down to steel on steel so its getting pretty dangerous, how much does it cost for a job like this, any suggestions would be great.

Thanks for the help above lads.

anthony4335

Try using a allen key that does not have a rounded end on it and ,hammer it into the bolt, this might do it.

bucks

qballirl wrote: »

how much does it cost for a job like this

Any decent mechanic will have it off in no time and you will just be charged for labour.

Aside from the danger of driving with pads steel on steel you may also damage the dics and if you do that you will have to get it either skimmed or replaced, further expense...

qballirl

bucks wrote: »

Any decent mechanic will have it off in no time and you will just be charged for labour.

Aside from the danger of driving with pads steel on steel you may also damage the dics and if you do that you will have to get it either skimmed or replaced, further expense...

Yeah tell me about it, its a case of end of the month syndrome no $$ so im gonna have to make do till the end of the month but cheers any way lads. Ill drop her into a garage.

DublinDilbert

I'm guessing by the 7mm allen bolts its an E36/E46.... although its a 7mm allen head, its difficult to take out these bolts using just an Alen key, this is possibly why you've damaged part of it. With an Allen key you can't get the torque in the right plane to remove the bolt, you'll just damage the head.


You'll need a 7mm Allen ratchet, which you can put a 3/8 or 1/2 ratchet into the back of.... If its not too badly damaged you'll probably be able to get it out like this...

If the head of the bold is damaged, you can just buy a new one, its item #6.
http://www.realoem.com/bmw/showparts.do?model=CA72&mospid=47435&btnr=34_0369&hg=34&fg=05

qballirl

Yeah cheers lad its an E36 just tried using the allen key will have a go at the allen ratchet, also cheers for the link it'll be part 13 alright. I might buy the part any way because it dosnt look promising if i have to change the brakes again.

crosstownk

First, get a new bolt.

Then: Hammer + Chisel. If you've room to swing the hammer you'll be grand. If you can cut a slot into the bolt head first it'll help.

qballirl

Ill give yous an update with pictures if i can lol, lucky im sprayin the car in january with all this hammering goin on.

10-10-20

Where is anybody going with WD40 near a set of brake calipers?
Two reasons why you don't use WD40 on brakes -
1. oil on the disk and pads. Manufacturers advise dumping pads which have ;been in contact with lubricant!!!
2. the WD40 could thin the lubricant on the sliding bolt mechanism and seize the brakes over time...!!!

bucks

10-10-20 wrote: »

Where is anybody going with WD40 near a set of brake calipers?
Two reasons why you don't use WD40 on brakes -
1. oil on the disk and pads. Manufacturers advise dumping pads which have ;been in contact with lubricant!!!
2. the WD40 could thin the lubricant on the sliding bolt mechanism and seize the brakes over time...!!!

Who said anything about putting it on pads/discs ?? :rolleyes:

CJhaughey

If/when you manage to get the bolt out make sure to wipe some copper grease on the threads before you replace it, it will pay dividends when you next have to do this job.

qballirl

I put it on the bolt not the brakes itself.

milltown

I always find, if a socket head screw (to give it it's proper name) gets rounded, the best way is to hammer in a Torx socket, slightly larger than the Allen one. The hammering in helps to break the seal between the male and female threads, and the splines of the Torx socket should give you enough grip to spin the bolt out. This has worked, I reckon, 95% of the time for me. The other 5% it's been a case of drilling, welding or gas bottles, depending on the application.

qballirl

CJhaughey wrote: »

If/when you manage to get the bolt out make sure to wipe some copper grease on the threads before you replace it, it will pay dividends when you next have to do this job.

Will certainly make sure of this, i wouldnt wish the same problem on any one.

MercMad

milltown wrote: »

I always find, if a socket head screw (to give it it's proper name) gets rounded, the best way is to hammer in a Torx socket, slightly larger than the Allen one. The hammering in helps to break the seal between the male and female threads, and the splines of the Torx socket should give you enough grip to spin the bolt out. This has worked, I reckon, 95% of the time for me. The other 5% it's been a case of drilling, welding or gas bottles, depending on the application.

........yep thats what I do and it always works !

I dont think you have mnuch alternative as these heads are flush with the caliper body if memory serves me correctly and you have no room to get a grips on, or weld anything !

Also there is no point in using WD40, its a water displacer NOT a penetrating fluid and more than likley the bolt is NOT seized there is simply a lot of threadlock on it. You may notice with a new set of pads, if they are a decent brand that new bolts are provided and you'll see the ring of blue threadlock on the threads !

Penetrating fluid will do nothing to threadlock !

BTW what you DONT want to do is put anti slip grease on here, the manufacturers put threadlock there so it DOESN'T come out ! Just clean the threads and use a new bolt and remember you DONT have to swing out of it when tighteneing, just nip it up !

Good luck !

sundodger5

if memory serves... when you push the piston back prior to taking out the pads you should be able to slide the caliper so that a load of the bolt is exposed. after that vice grips and a new bolt.

qballirl

Yeah will get the vice on it see what happen it does stick out a bit from the caliper so there is a bit of give.

WD40 im sure this was pentrating oil.

JohnCleary

These allen bolts are a pig, been there, done that a few weeks ago on my own e46.

Not much good to you now, but for future reference, what I did:

I guessed they would be right (lots of crud around that area) so I tapped the bolt with a hammer a bit before trying to loosen them. Then in with the allen key (with very long 'long' end, if you get my drift) and gave a little tap with that too. Then I got a small bar (about 2ft long) and stuck it into the long end of the allen key to give a big of leverage. It eventually gave.

As was advised above, next time get a bit. I need to take my own advise and get one for the next brake pad change too!

On a lighter note, suspension/brake work on the E46 is a total doddle which is great, I presume it's the same with the E36?