Impact Wrench

Jez

Jez

Jez

Caporegime
Joined
18 Oct 2002
Posts
33,073
Hi,

I tried to change the discs on a car earlier this week, i totally failed as i couldn't for the life of me crack the caliper bolts loose.

Am i right in thinking that it would have been a really easy job had i had an impact wrench (if that is even the right term?).

If so, what would people recommend for occasional DIY use?
 
You can get the manual ones (where you smack them with a mallet or similar) or powered ones.

Powered ones are a bit dire unless you spend some serious money, but then you are almost in to air gun territory.

A decent breaker bar should do the job if you can get in easily enough
 
I've used it to remove my front VW caliper hangers when fitting the Brembos, like i say it should do the job, what you may find is simply giving the bolt a few blasts with this will enable you to remove them fully by hand.

When i was doing the Hub Bolts i had no chance of removing them by hand, even with a breaker bar and tube, buzzed them several times with this, stuck a normal socket on and they came off with limited force.
 
Maybe worth a slight tighten first 1/8 - 1/10 of a turn to help break any rust. Possibly give it a little strike on the also.

Also consider using some penetrating fluid first put on a few times a day or two before (if you can wait that long).

When undoing a bolt I prefer a quicker action rather than slowly loading it which is less likely to shear it.
 
Jez said:
Cant get any form of long bar or extension inside a wheel arch for caliper bolts on the back of the caliper assembly sadly :(

Firestar - that looks just the job, if they really will crack anything.
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Not even if you put the steering on full lock so the caliper is pointing outward? Even if you can only move the bar a few inches it'll be enough to crack it loose so you can get it the rest of the way with a standard ratchet/socket
 
Yeah, even on full lock the spanner was still inside the wheel arch.

Its in a local garage having them installed now, its annoying as its such an easy job. They will have it done in 20mins using their air tools i would imagine. Oh well :)

Firestar - that wrench sounds great, i like the idea of using it to take wheels off too, as they are often pretty solid too.
 
Jez said:
Yeah, even on full lock the spanner was still inside the wheel arch.

.
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Breaker bar + a length of metal pole or something is the best way (I use a bike saddle post), so it protrudes from under the car and you can exert pressure on it :) Anyway it's irrelevant now :)
 
Would have been nice to have done it myself given that it looked so easy, and i do appreciate the advice.

I perhaps should have persevered but you know what its like when you dont *really* know what you are doing and then suddenly get that out of your depth feeling, that forcing stuff might end up breaking more than you bargained for, all to save a 50 quid garage bill :p

I think i will get one of those impact wrenches anyway for future use though..
 
Ha, that would go against my new plan of not spending anything on it as its now not worth anything and just needs to be nursed for work mileage until it becomes so rusty that its an eyesore. The plan was to just give it oil every 15 or so thousand, and nothing else unless it actually breaks down.

This new plan worked for about 3 days, but now it needs a new crank position sensor, new brakes, new tyres, and an MOT. So it looks like i will never get away from its relentlessness.

Joys :p
 
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Things really do break for fun on it then :\

What's so special about things like a Mercedes CPS over one that Honda use? ;)
 
I dont know, I dont even know what it does :p

I just know that the car has failed to start twice now when left for sub 30mins and still warm, which seems to be a common CPS failure from what i can tell from reading up. I am yet to get a diag to confirm it but i think it will definitely be that as mine is original and the symptoms match perfectly.

I'll get it to the Mercedes specialist in reading for that i think, they will have no doubt seen it 100* before :)
 
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Jez said:
Joys :p
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In the same boat with my DC2.

Not picking it up today (work started day of the south hampshire meet of win win11), but heading down there to authorise an arch rebuild.

Found out that a previous rusty arch being sorted was't done properly and teh inner arch has rusted away. Thus even more money onto a bill for all works probably coming to easily over 1/2 of what I payed.

Stupid cars, but I love them and I can't wait to get her back and strip her bolts off giving her some nice new grease and bolt action :D:D
 
Whats annoying is that i dont even have any interest in the car any more, i have been running a second (well, third between myself and my GF) alongside it for personal/weekend use. The S-Class is purely for work, thrashing up and down the motorway network to customer sites.

All these bills (and moreso the hassle) are just annoying, as i have no real interest as such in it.

Oh well, cars :p
 
As i say, its annoying, but thats as far as it goes. I like the car and i believe that it is still the best possible car i could have for the usage it gets :) There is nothing sub £30k (that being the price of an early used W221 S-Class) which will be better and therefore it makes sense to keep it.
 
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