Steering knuckle bolt removal - any strong' ideas ?

[grasmere]

I prepared to change my front lhs wheel bearing today and all was going great - until I tried to undo the two 17mm bolts holding the brake caliper to the steering knuckle thingy! This needs to come off to remove the disc.

Tight? oh yes. They are supposed to be tightened to 85 lb ft so its not really surprising I guess and they will not have been off since new in 1996 and 87k miles.

Any ideas guys apart from a ramp and a looooong lever.

Perhaps a trip to a local indy and a fiver to crack them loose . . .

 

[willy]

i would use a 17mm impact socket (with six point) as these don't round the nuts, if u try to use normal 17mm socket it will round the nuts.

other tips wd40 & heat

 

[andy_k]

when I did mine it was as Willy suggested using an impact socket and my torque wrench - gentle persuasion with the aid of a 2' long bar and they went with one heck of a crack

Give them a tap with a hammer before removing them that may "loosen" them.

Just as an aside - are you aware that they are a "single use" bolt and should be replaced with new ones when you reassemble and it's recommended you don't use copper grease on the threads ?

HTH

Andy

 

[grasmere]

Thanks Will and Andy, by 'impact' do you mean a special pointed socket or an 'impact driver' with a socket, ie that you belt with a hammer ?

Oh and yes thanks Andy, I got 2 in the wheel bearing kit, complete with inner and outer bearings and races plus the inner oil seal and new disk retaining allen bolt.

 

[andy_k]

I just mean a socket that is impact rated, they are a lot tougher so won't split under stress and are generally 6 sided so as Will says they are less prone to slipping.

Andy

 

[pluggers]

A little tip if you dont already know is to turn your wheel outwards to gain better access and more leverage.I used a normal socket attached to a breaker bar not more than 24" long I think and didnt require too much effort.

 

[Will]

As Andy and Will said - use an impact socket (or if not, at least a decent 6-point socket) and some brute force!

They WILL come off. The reason that they are difficult to remove (other than the fact that it has been on there for ages ) is that they are 'thread-locked' bolts, hence part of the reason that they 'single use'.

It's amazing what a bit of leverage can do.

Good Luck, and I hope it goes ok.

Will

 

[Satch]

Sometimes helps to "shock" the bolt first to help break any adhesion in the threads.

Absent an impact driver attach a bar to a strong socket and strike with a decent size hammer or indeed any metal object. You need a short bar or strike a long one near the socket or the natural flex in the bar will tend to absorb the impact.

You are not trying to hammer the damn thing out nor get anywhere near the horrible prospect of shearing the bolt (woe, woe and thrice woe!) just applying a moderate short duration pulse much like that an impact driver would ordinarily produce.

As ever, common sense and judgement required in terms of applying force but so far has worked for me when faced with the Bolts From Hell

 

[Sp!ke]

I have in the past been extreamly surprised by a little 12V impact gun from Clarke.

Its very cheap and works surprisingly well at removing stubborn bolts.

http://www.machinemart.co.uk/product.asp?p=060810013

 

[nickmann]

If it's that tight and you're worried about rounding it off, then try tightening it first to crack the adhesion. Then at least if you DO round if off you can still undo it.

Failing that you could try waving a few beer vouchers down at your local exhaust place.

 

[grasmere]

some great tips guys, thanks a lot. That should get me sorted. I bought a set of black impact six sided sockets today. I also remembered I put in my wifes car one of those extendable wheel wrenches so that will be useful.

surprised by a little 12V impact gun

Thanks spike, I will keep that in mind. I did have a laugh looking at the handle of that impact gun with torque output up to 115ft lbs. Imagine an unsuspecting guy using it on a tough nut and spinning round like the cartoon cat

 

[Satch]

Thanks spike, I will keep that in mind. I did have a laugh looking at the handle of that impact gun with torque output up to 115ft lbs. Imagine an unsuspecting guy using it on a tough nut and spinning round like the cartoon cat

Handy device indeed, but note it could be more like if you use one of those on some types of locking wheel nuts.

 

[grasmere]

all sorted now guys, thanks for your help, the tips on length of breaker bar and turning the wheels out made all the difference to getting the bolts out.

Total cost by the way for both sides inc new guide pin bolts, approx £75

only query I have now is that the noise I thought was wheel bearings, backed up by a 12 and 6 o'clock shakedown, is still there, perhaps its the brakes

Ah well, at least I know it isn't the wheel bearings