Hot wheel - burning rubber - Page 2

savabill · Nov 13th, 2015, 20:01

Stab in the dark. Your slide pins are sticking slightly, causing the pads to catch slightly on the disc. Friction warms the disc and the pads, they expand and this makes them catch even more. This is where your heat is coming from. When it all cools down everything contracts and allows the disc to spin. New discs and pads, should sort it out. If I was you, I would change the fluid as well. It must have been nearly at boiling point.

John Underhill · Nov 22nd, 2015, 12:41

Well, I've finally got round to stripping this wheel down and other than a lot of rust in the brake shoe cavity and a weak hold in spring, I can't see anything obviously wrong. The pads and calliper bracket were well rusted up, but the guide pins were fine.

My only concern is the hub. It turns very smoothly and there is no play, but without the brake disc on it is dead with absolutely no freewheel whatsoever. I know it is full of grease but I would have expected it to turn more freely.

Is this the normal state?

I'm trying to ascertain if it's OK so I can rebuild the wheel with new disc and pads and as I can only lift one side at a time I can't compare with the other wheel yet! Your advice welcomed please.

Paul240480 · Nov 22nd, 2015, 13:04

+1 on off-sided, both on my 850 & V70, the latter having aluminium 'stops' , snapped the 'stop' straight off and locked the wheel up

. Fixed with a 'stop-repair kit' tho not a new hub!

Anyways hope you sort yours! Good luck.

savabill · Nov 22nd, 2015, 13:39

Have you checked to see that its full of grease? Heat could have melted it. The rust on the pad and caliper brackets could have held the pads onto the disc. The hub should be stiff to rotate, but not solid.

John Underhill · Nov 22nd, 2015, 15:10

Well I've now answered my own question! I managed to get the other rear wheel in the air and stripped it down and found that the hub resistance is the same on both sides so I'm assuming the errant off-side wheel hub is OK. I've rebuilt the "good" side with new disc and pads and will do the other side tomorrow. There is still a nagging question as to whether the caliper is at fault, it screwed back in without any problems and I guess I won't know until I finish the other side and have a run out. At least I now have confidence in the handbrake shoes, caliper guides, discs and pads all being OK

Brendan W · Nov 22nd, 2015, 15:25

I would expect a hub to spin 'freely' with the wheel on because of the mass of the wheel.
I would not expect a properly packed hub to spin 'freely' with the wheel off no matter how hard I tried to flick it. If it did I would suspect the grease had run out. From memory normal Lithium greases melt at about 140C - easily reached with a sticking brake. Perhaps I will devise a test involving a pot of jam as a weight and some string.

John Underhill · Nov 25th, 2015, 18:18

Well, completed the new discs and pads change successfully over the weekend but a short 3 mile trip got the OSR pads smoking again

I have decided to bite the bullet and have ordered 2 new callipers from PFV which will hopefully solve the problem

bournricha · Nov 25th, 2015, 18:50

.The piston could be rusty or the seal swollen .I usually try to strip them ,gently emery the piston if it is not too bad and fit a new seal kit .But sometimes they are too far gone to save and you have to replace .Rear calipers always seem to get in a worse state than front ones .i have not yet failed to overhaul a front one but have replaced a few rear ones when I simply could not remove the piston .Lets hope the calipers do the trick .If it does not I think I would begin to think about the ABS valves .We have had a recent case in the c70 site of a valve sticking open and allowing pressure to release .I wonder if the reverse could be the case and pressure could be held on .Just a bit of out of the box thinking in advance ,because I don't quite get how the brake is releasing when you try it on the jack and then not releasing on the road .In my experience ,if they are stuck ,they stay stuck .

ShadeTek · Nov 25th, 2015, 21:31

Rebuilding a caliper is not difficult. It is very cheap and easy to do. More than likely you have a crudded up piston which can be cleaned and refitted. Here is a video how to.

+ YouTube Video

D5meister · Nov 25th, 2015, 21:43

you would have had to push the piston back to fit the new pads - did the piston go in ok - guess it did.

Was it the same both sides?

Ive had sticky pistons on cars that have never swapped the brake fluid and the water content of the fluid eats the piston

or

motor bikes where the caliper body is alloy and the oxide crust build up under the seal makes the seal crush onto the piston

Nov 13th, 2015, 20:01	#11
savabill Master Member Last Online: Yesterday 19:39 Join Date: Aug 2013 Location: doncaster	Stab in the dark. Your slide pins are sticking slightly, causing the pads to catch slightly on the disc. Friction warms the disc and the pads, they expand and this makes them catch even more. This is where your heat is coming from. When it all cools down everything contracts and allows the disc to spin. New discs and pads, should sort it out. If I was you, I would change the fluid as well. It must have been nearly at boiling point. __________________ Only My Opinion: Good luck. Bill NOW 59 REG 2.5T V70 Ice White SOLD 55 REG T5 V70 Ruby Red

Nov 22nd, 2015, 12:41	#12
John Underhill Junior Member Last Online: Mar 15th, 2024 21:21 Join Date: Jan 2007 Location: Didcot	Hub advice please! Well, I've finally got round to stripping this wheel down and other than a lot of rust in the brake shoe cavity and a weak hold in spring, I can't see anything obviously wrong. The pads and calliper bracket were well rusted up, but the guide pins were fine. My only concern is the hub. It turns very smoothly and there is no play, but without the brake disc on it is dead with absolutely no freewheel whatsoever. I know it is full of grease but I would have expected it to turn more freely. Is this the normal state? I'm trying to ascertain if it's OK so I can rebuild the wheel with new disc and pads and as I can only lift one side at a time I can't compare with the other wheel yet! Your advice welcomed please. __________________ 52 Silver V70 D5 SE Manual

Nov 22nd, 2015, 13:04	#13
Paul240480 Ovlovnut Last Online: Feb 25th, 2024 08:58 Join Date: May 2006 Location: Nivillac View Photos By: Paul240480	+1 on off-sided, both on my 850 & V70, the latter having aluminium 'stops' , snapped the 'stop' straight off and locked the wheel up . Fixed with a 'stop-repair kit' tho not a new hub! Anyways hope you sort yours! Good luck. __________________ 2004 V70 2.4SE Auto 'The Welshmobile’ 2002 Laika Ecovip 400i ( Motorhome on an Iveco 2.8TD) http://www.gitessouthbrittany.com/ http://moncopainmonchien.jimdo.com/

Nov 22nd, 2015, 13:39	#14
savabill Master Member Last Online: Yesterday 19:39 Join Date: Aug 2013 Location: doncaster	Have you checked to see that its full of grease? Heat could have melted it. The rust on the pad and caliper brackets could have held the pads onto the disc. The hub should be stiff to rotate, but not solid. __________________ Only My Opinion: Good luck. Bill NOW 59 REG 2.5T V70 Ice White SOLD 55 REG T5 V70 Ruby Red

Nov 22nd, 2015, 15:10	#15
John Underhill Junior Member Last Online: Mar 15th, 2024 21:21 Join Date: Jan 2007 Location: Didcot	Well I've now answered my own question! I managed to get the other rear wheel in the air and stripped it down and found that the hub resistance is the same on both sides so I'm assuming the errant off-side wheel hub is OK. I've rebuilt the "good" side with new disc and pads and will do the other side tomorrow. There is still a nagging question as to whether the caliper is at fault, it screwed back in without any problems and I guess I won't know until I finish the other side and have a run out. At least I now have confidence in the handbrake shoes, caliper guides, discs and pads all being OK __________________ 52 Silver V70 D5 SE Manual

Nov 22nd, 2015, 15:25	#16
Brendan W Premier Member Last Online: Apr 2nd, 2024 19:50 Join Date: Dec 2007 Location: Wexford	I would expect a hub to spin 'freely' with the wheel on because of the mass of the wheel. I would not expect a properly packed hub to spin 'freely' with the wheel off no matter how hard I tried to flick it. If it did I would suspect the grease had run out. From memory normal Lithium greases melt at about 140C - easily reached with a sticking brake. Perhaps I will devise a test involving a pot of jam as a weight and some string.

Nov 25th, 2015, 18:18	#17
John Underhill Junior Member Last Online: Mar 15th, 2024 21:21 Join Date: Jan 2007 Location: Didcot	Back to Square One! Well, completed the new discs and pads change successfully over the weekend but a short 3 mile trip got the OSR pads smoking again I have decided to bite the bullet and have ordered 2 new callipers from PFV which will hopefully solve the problem __________________ 52 Silver V70 D5 SE Manual

Nov 25th, 2015, 18:50	#18
bournricha bournricha Last Online: Jan 10th, 2017 22:14 Join Date: Jan 2014 Location: oban	.The piston could be rusty or the seal swollen .I usually try to strip them ,gently emery the piston if it is not too bad and fit a new seal kit .But sometimes they are too far gone to save and you have to replace .Rear calipers always seem to get in a worse state than front ones .i have not yet failed to overhaul a front one but have replaced a few rear ones when I simply could not remove the piston .Lets hope the calipers do the trick .If it does not I think I would begin to think about the ABS valves .We have had a recent case in the c70 site of a valve sticking open and allowing pressure to release .I wonder if the reverse could be the case and pressure could be held on .Just a bit of out of the box thinking in advance ,because I don't quite get how the brake is releasing when you try it on the jack and then not releasing on the road .In my experience ,if they are stuck ,they stay stuck . __________________ 1991 940 estate 2.3 125,000m.Under overhaul Previous convictions ;s70 ,855t5,745,v70, v70p2

Nov 25th, 2015, 21:43	#20
D5meister Premier Member Last Online: Feb 10th, 2024 19:13 Join Date: Nov 2008 Location: Huntingdon	you would have had to push the piston back to fit the new pads - did the piston go in ok - guess it did. Was it the same both sides? Ive had sticky pistons on cars that have never swapped the brake fluid and the water content of the fluid eats the piston or motor bikes where the caliper body is alloy and the oxide crust build up under the seal makes the seal crush onto the piston

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