au wagon brake shuddering under brakes

HARMFUL 81 · 06-01-2009, 10:32 AM

Hi there everyone.
I have an au wagon on which about 6 months ago i replaced the front rotors and pads (slotted with bendix pads) due to warped standard discs. However it has developed shuddering again. Is this likely to be the discs again this early? is there any other likely problems - bearings/wheel balancing? The shuddering only happens when braking, although if the brakes are applied harder, their is no pulsating. Hope this all makes sense.

**FTE217** · 06-01-2009, 11:10 AM

Mate got to do the job again I'm afraid, well not totally but have to clean the hub face where the rotor sits. Once you have taken the rotor back off you will see its a black face due to road grim grit build up, get some emery paper and a can of WD40, clean till shiny clean face even around the wheel studs.
Sure this will solve your shudder a often over looked part of the job.

HARMFUL 81 · 06-01-2009, 11:16 AM

yes Bluedriver, it was an overlooked part of fitting the rotors, will try that. I recently had the tyres replaced, maybe when refitting the rotors werent fastened exactly square due to what your saying. other then that maybe balancing of the front wheels?

adrian k · 06-01-2009, 03:48 PM

Quote:

Originally Posted by Bluedriver

Mate got to do the job again I'm afraid, well not totally but have to clean the hub face where the rotor sits. Once you have taken the rotor back off you will see its a black face due to road grim grit build up, get some emery paper and a can of WD40, clean till shiny clean face even around the wheel studs.
Sure this will solve your shudder a often over looked part of the job.

Just rectified this problem on my TS, it was build up from an anti rust spray i put on the faces. it doesn't take much dirt to make em wobble.
Race brakes told me that warped discs are a myth, its usually variations in disc thickness (DVT) or run out.

**FTE217** · 06-01-2009, 03:59 PM

Quote:

Originally Posted by HARMFUL 81

Hi there everyone.
I have an au wagon on which about 6 months ago i replaced the front rotors and pads (slotted with bendix pads) due to warped standard discs. However it has developed shuddering again. Is this likely to be the discs again this early? is there any other likely problems - bearings/wheel balancing? The shuddering only happens when braking, although if the brakes are applied harder, their is no pulsating. Hope this all makes sense.

Hence your problem not wheel balancing........clean those surface's spotless including now inside face of the rotor which sits on the hub and you should be right.

HARMFUL 81 · 07-01-2009, 09:55 AM

thanks guys. Last night i pulled the discs off and cleaned the surfaces as mentioned. Seams to help a bit, but the problems not completely gone. I also noted that on the inside of the discs there seamed to be an area on the disc that looked to have less contact then the rest. I have concluded that this could be due to the reason mentioned before. I think ill wait for it to clock up a few more kays on the 'Fixed" alignment and see how it develops.

adrian k · 07-01-2009, 02:39 PM

If you are 100% sure the mating surfaces are good (i was told by DBA to get them like you would get a head when replacing a head gasket), then get them machined, and then run them in properly. you could also have patches of build up on the discs. the run in process is very important to eliminate build up which is not always visible.