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D4B
Joined: 28 Dec 2010 Posts: 2083 Location: Hampshire UK
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Posted: Fri Sep 09, 2016 5:41 pm Post subject: What can cause drum brakes to squeal? |
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I rebuilt my Land Rover series 3 drum brakes with many new parts prior to the MOT test in May, and to start with performed as they should without so much as a peep.....
Gradually they began to squeak during braking, and this has since turned into loud squealing every time the brake is applied. I have dismantled and dusted them down, reassembled and adjusted, but still they squeal!
Any suggestions very welcome.
Thanks Steve |
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kevin2306
Joined: 01 Jul 2013 Posts: 1359 Location: nr Llangollen, north wales
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Posted: Fri Sep 09, 2016 7:49 pm Post subject: |
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Have the shoes overheated and become glazed perhaps?
Kev |
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D4B
Joined: 28 Dec 2010 Posts: 2083 Location: Hampshire UK
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Posted: Fri Sep 09, 2016 9:15 pm Post subject: |
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Hi Kev, thanks for your prompt reply.
No there was no sign of glazing over, besides, i wire brushed them off before refitting the drums, also there are chamfers at ends of the linings. |
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jp928
Joined: 07 Jun 2016 Posts: 249 Location: Australia
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Posted: Sat Sep 10, 2016 2:58 am Post subject: |
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Are there signs of the lining to drum contact not covering the the lining completely? Were the relined shoes radiused to the drum ? This involves running the shoes over a grinder so the linings have the exact same radius curved face as the drum. Should be done to suit each individual drum.
jp 26 Rover 9 |
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D4B
Joined: 28 Dec 2010 Posts: 2083 Location: Hampshire UK
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Posted: Sat Sep 10, 2016 9:59 am Post subject: |
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jp928 wrote: | Are there signs of the lining to drum contact not covering the the lining completely? Were the relined shoes radiused to the drum ? This involves running the shoes over a grinder so the linings have the exact same radius curved face as the drum. Should be done to suit each individual drum.
jp 26 Rover 9 |
Hi JP, no i didn't do that, and you could be onto something there, but you may need to explain the process to me in more detail..... |
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Peter_L
Joined: 10 Apr 2008 Posts: 2680 Location: New Brunswick. Canada.
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Posted: Sat Sep 10, 2016 1:06 pm Post subject: |
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It can be caused by having the wrong design shoe. i.e leading and trailing design compatible with the cylinder and pivot points. |
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jp928
Joined: 07 Jun 2016 Posts: 249 Location: Australia
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Posted: Sat Sep 10, 2016 1:15 pm Post subject: |
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When shoes are relined, assuming the new linings are exactly the same thickness as the originals, and the drums are still same diameter as new, all should be well. If the linings are different or the drums machined, the shoes need grinding. The drum dia is measured and a special machine set to that diameter, and each shoe (for that drum) is mounted and run past a grinding wheel so the effective radius of the shoe matches the drum exactly.
All the brakes on my car have been relined and machined before my time, so I may be confronted with the same issue.
This link may help
http://www.autoandindustrial.co.uk/index.php?webpage=radius-grinding
Note the bit at the end about shoes anchored at one end with a cam at the other needing special attention in this regard.
jp 26 Rover 9 |
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D4B
Joined: 28 Dec 2010 Posts: 2083 Location: Hampshire UK
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Posted: Sun Sep 11, 2016 2:13 pm Post subject: |
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Thanks jp, as new brake drums are just £13.50 each, i might try a pair of those next...... |
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D4B
Joined: 28 Dec 2010 Posts: 2083 Location: Hampshire UK
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Posted: Sat Sep 17, 2016 1:53 pm Post subject: |
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D4B wrote: | Hi Kev, thanks for your prompt reply.
No there was no sign of glazing over, besides, i wire brushed them off before refitting the drums, also there are chamfers at ends of the linings. |
There WAS signs of glazing over, no doubt caused by the drum not matching the shoes profile as per JP's suggestion.......
New brake drums installed this morning, shoes de glazed,
and all is quiet now thank goodness!
Thanks all for your advice
Steve |
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kevin2306
Joined: 01 Jul 2013 Posts: 1359 Location: nr Llangollen, north wales
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Posted: Sat Sep 17, 2016 8:57 pm Post subject: |
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Glad you are sorted Steve,
Nothing worse than noisy brakes.
Kev |
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BigJohn
Joined: 01 Jan 2011 Posts: 954 Location: Wem, Shropshire
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Posted: Sat Sep 17, 2016 9:56 pm Post subject: |
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Oh I don't know, I'd take noisy brakes over no brakes.
(sorry couldn't resist, I'll get my coat) |
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