Caliper problem
10-11-2010, 03:19 PM
#1
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Caliper problem
After doing the discs and pads all round recently, I drove back to Scotland with no imminent problems.
After a brief run there was a grinding noise coming from the rear left disc. After investigation I found the inside of the disc was half worn - the inboard pad was only contacting half of the disc.
I pulled back the disc shield to find the pad was sitting at an angle on the disc. I took the caliper off and checked if it was seized by pressing on the brake pedal ( with master cyllinder lid off ). It worked fine and i checked a couple of times!
Put it all back together with the pad sitting flush and gave her a short drive. Jacked her up and found that once again the pad had gone to the slanted position. I repeated this 3 times and still the problem persisted
And whilst I was there I noticed that the hub nut was loose, The witness marks still lined up like it was a manufacturer marking. I tightened it up and again the problem persisted.
Drove back to hampshire yesterday and today she was grinding again
Has anybody had a similar problem or can shed some light?!
Cheers
Marc
After a brief run there was a grinding noise coming from the rear left disc. After investigation I found the inside of the disc was half worn - the inboard pad was only contacting half of the disc.
I pulled back the disc shield to find the pad was sitting at an angle on the disc. I took the caliper off and checked if it was seized by pressing on the brake pedal ( with master cyllinder lid off ). It worked fine and i checked a couple of times!
Put it all back together with the pad sitting flush and gave her a short drive. Jacked her up and found that once again the pad had gone to the slanted position. I repeated this 3 times and still the problem persisted
And whilst I was there I noticed that the hub nut was loose, The witness marks still lined up like it was a manufacturer marking. I tightened it up and again the problem persisted.
Drove back to hampshire yesterday and today she was grinding again
Has anybody had a similar problem or can shed some light?!
Cheers
Marc
10-11-2010, 11:21 PM
#3
there is a nipple that sticks out of the back of the inner pad which needs to sit in the groove that runs across the piston.
If you didn't line up the piston correctly then that may well explain why your pad tipped.
Once it has tipped and worn unevenly you will never get it to sit correctly and it needs replacing.
As for the hub nut, the hub nut should be staked to prevent it coming loose.
If its loose you need to get a new nut, tighten it to the required torque setting (220NM from memory) and stake the nut.
Unless the hub nut its secure i wouldn't drive the car. You are at risk of that hub detaching itself from the car.
10-11-2010, 11:49 PM
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The inside pad has only worn on the outer edge of the disc.
When you reassemble the pads correctly, the outside pad will contact the disc on the inner edge of the disc only.
Since you have only recently changed the pads I would let them wear correctly, prob take the same amount of miles.
When you are reassembling make sure the pin is aligned in the crossshair by looking through the vent on the top of the caliper.
Align the crosshair with the vent before placing it on the pads for a reference mark.
When you reassemble the pads correctly, the outside pad will contact the disc on the inner edge of the disc only.
Since you have only recently changed the pads I would let them wear correctly, prob take the same amount of miles.
When you are reassembling make sure the pin is aligned in the crossshair by looking through the vent on the top of the caliper.
Align the crosshair with the vent before placing it on the pads for a reference mark.
10-12-2010, 01:48 AM
#5
Presuming the pad is correctly seated in the anti-rotation groove, then the clue is in the loose hub.
The pad's perpendicular; the disc ain't.
Sounds like serious attention required urgently.
The pad's perpendicular; the disc ain't.
Sounds like serious attention required urgently.
10-12-2010, 08:23 AM
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Cheers for the input guys.
I did re-tighten the hub nut and restake by the way but just tweaked it as the torque wrenches are in work.
As for the pads, I was not aware there was a pin to line up with the piston so cheers for that!
I was contemplating filing off the excess paint on the edge of the pad where it sits in the shim and re-grease allow it to move more freely.
There is no massively excessive wear on the disc or the pad as Ive been using the brakes as little as possible
I did re-tighten the hub nut and restake by the way but just tweaked it as the torque wrenches are in work.
As for the pads, I was not aware there was a pin to line up with the piston so cheers for that!
I was contemplating filing off the excess paint on the edge of the pad where it sits in the shim and re-grease allow it to move more freely.
There is no massively excessive wear on the disc or the pad as Ive been using the brakes as little as possible
10-12-2010, 10:26 AM
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Ok an update. I just removed the caliper and lined the grooves on the piston with the notches on the pad.
The grinding noise is still there. I span the disc with the pad back on and there was no grinding noise but a small (very faint whisper of a noise from the inner side of the driveshaft.
The noise gets louder going round right hand corners and almost dissapears when on left handers which leads me to a wheel bearing
Any ideas gents??
Marc
The grinding noise is still there. I span the disc with the pad back on and there was no grinding noise but a small (very faint whisper of a noise from the inner side of the driveshaft.
The noise gets louder going round right hand corners and almost dissapears when on left handers which leads me to a wheel bearing
Any ideas gents??
Marc
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10-12-2010, 11:35 AM
#8
Hi i have recently had a gringing noise which did not sound like a bearing but it was if you do a search for my recent posts there is a link to a you tube video if it sounds like that then its a bearing.
10-12-2010, 12:29 PM
#9
Before you start spending, check for a trapped stone between the disc shield and the disc. Just a thought!
10-13-2010, 08:51 AM
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Originally Posted by sharksfinn,Oct 12 2010, 11:35 AM
Hi i have recently had a gringing noise which did not sound like a bearing but it was if you do a search for my recent posts there is a link to a you tube video if it sounds like that then its a bearing.
Its almost exactly the same noise. My next step was to order 2 new rear hub nuts and torgue them up correctly!
I just hope it is the root of the problem!
I also found the hub nut loose last week, retightened in as best i could with mole grips but it came back soon after. I obviously never tightened enough!
Cheers and here's to hoping
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