Brake Discs, What the *!$%

[chadders]

Hello all

I decide to be brave and do my own brake disc change (front), on beloved 2.5

Problem is that the passenger side will not come off - drivers side=two taps with hammer&wood combo OFF - other side no movement at all!!!

Any suggestions, or is this a brute-force moment?

This post has been edited by chadders on July 23, 2006 06:11 pm

[franpa2]

Hi Chadders,
I had exactly the same problem on the passenger side disc ,it was very stubborn and it was just down to brute force as you say (hitting on opposite sides ). I can't think of an easy way to do it and would be interested if anyone else can .
regards Tony

[Peter.N.]

No, the only way is to use a bigger hammer!

Peter.N.

[xmexclusive]

Hi Chadders

If they are scrap why are you worried about giving them a good clout?
If they are reuseable why are you changing them?

Regards

XMexc

[chadders]

I'm not worried about the discs, I just didn't want to wreck anything else if I gave them a good clout - as you say!

3 people say that when they nod their head I should hit it - SO who am I to argue?!?!

Seriously though guys, THANKS for vote of confidence...

[xmexclusive]

Hi Chadders

Hope you have not bought the new disks for the 2.5 as it sounds as though you have a very servicable set on the scrap 2.1 TD.

Regards

XMexc

[noz]

Hi Chadders,

One word of caution (unless I'm too late already). The element which resists the hammer blows is the front wheel bearing. You don't want to be banging it too hard otherwise you'll damage the races of the bearing leading to premature failure. The best way I've found is to clean up the centre of the disk where the hub pokes through as best as you can with a wire brush. Then use plenty of release oil and leave for a couple of days to soak. Then use a puller and get some tension on the disk before hitting with a mallet first before you try a hammer. Pre-tensioning the disk makes the hammer blow more efficient hence a small er blow will be needed to release the disk. It is only being kept on by a thin film of rust which has built up in the little space between the disk and the hub.

There's no doubt at all that laying into it with a hammer will get it to release but you may just damage the wheel bearing in the process.

I take it you have removed the small Torx set screw which holds the disk on?

cheers

noz

[xmexclusive]

Hi Chadders

Trust Noz to explain why I must not use a sledge hammer on the front disks next time. The XM front wheel bearings seem a little feeble to me. I knew they did not like the heat from binding brakes but I thought that a good clout never did any harm.
Sorry to give duff advice.

Regards

XMexc

[chadders]

Well guys,

XMExc: Had already bought discs!!!!!!

Noz: Thanks for further info, will try that...had already used a 2.5lb lump on them though (and WD40) STILL BLOODY THERE THOUGH

What is "a puller", and just for info are bearing same as 2.1?

Ta

[noz]

Hi Chadders,

Here's a photo of my puller. Its a devoce for pulling anything round off a shaft. The three legs would hook around the edge of the thing to be pulled off (in your case the disk) and the middle would screw into and press ont the centre of the hub. This way, no forces are transmitted to the bearing.

Sorry for the photo quality but it was quite dark when I took it and the autofocus doesn't like the dark.

Cheers

noz

[citroenxm]

Hi All

Car mechanics did a feature on an XM 2.1 TD a while ago. They wanted to change front disks, but they had to use a grinder and chisel of some sort to split the disk to get it off....

I changed a hub on passenger side of car on Ebay before MOT, and the passenger side disk FELL off after removing screws..

Regards
citroenxm

[noz]

If the disks have ever been off since new, even once, the chances are that some kind person would have smeared the new ones with grease around the point where they contact the hub. In which case they'll always come off dead easy in future.

I've just been through exactly this scenario two weeks ago having fitted new disks to the front of the 2.5 before towing the caravan with it over to France. Having cleaned up the hub with a rotary wire brush and greased the centre hole, the disks now come off and on really easily.

cheers

noz

This post has been edited by noz on July 25, 2006 11:10 pm

[chadders]

Aha, I've seen them before - never knew purpose though!

Will try that before invoking mobile mechanic...

Cheers Noz et al

[bigjohnh]

Chadders,

The other way traditionally used for parting siezed parts is the careful application of heat. The expansion of the outer part together with the skilful application of some gentle persuasion (a hammer) often frees the parts. BE VERY CAREFUL. It would be very easy to end up with your pride and joy as a viking funeral. I generally stick to one of those electric paint stripping guns for safety and always work outdoors not in a garage with all sorts of solvents and other vapours in an ecclosed space. The object is to heat the outer object, ie the disc, without heating the inner hub too much. This gives differential expansion between the parts which helps to free the stuck bit but take care not to melt any vital pipes or trim or damage the hub.

Get a friend to watch whilst using heat as it is really easy to get engrossed and forget to turn the gun off or something and have a bucket of water or a hose handy just in case.

I have seen 'old hands' heat a recalcitrant part with oxy-acetelene with miraculous results due to the high heat difference. Definitely not recommended unless you really know what you are doing and have some industrial fire extinguishing equipment to hand.

Best of luck

bigjohnh

[chadders]

THANKS TO ALL

With use of puller and 2kg lump hammer, the b#''#'y thing came off.

Amazing what can happen with the right tools (and advice)