Date: 28-03-24  Time: 11:41 am

Author Topic: Rear brake clunk/hot  (Read 2246 times)

Steve3351

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Rear brake clunk/hot
« on: 09 July 2019, 03:29:57 pm »
Hi Foccers..
I notice that my rear brake is not working too good...then when i stand on it something seems to move, and then CLUNKS back when i come off the brake... also i notice that the rear disc is VERY hot after a spin...even tho i mostly use the front brake...any thoughts...? :guitar

Actually i had this same prob a year ago...and burnt my thumb quite badly on a RED HOT disc... :eek ..  paid €300 to highly reputable shop in Dublin for fixing..
.i thought at the time...JAYSUS...!
it wud have been cheaper to fit a new caliper...???!!
« Last Edit: 09 July 2019, 04:56:53 pm by Steve3351 »

BBROWN1664

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Re: Rear brake clunk/hot
« Reply #1 on: 09 July 2019, 03:48:20 pm »
Sounds like a sticky caliper. It will need stripping and cleaning.
Another ex-Fazer rider that is a foccer again

Steve3351

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Re: Rear brake clunk/hot
« Reply #2 on: 09 July 2019, 04:57:27 pm »
Do i need a service kit...?

His Dudeness

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Re: Rear brake clunk/hot
« Reply #3 on: 09 July 2019, 07:48:29 pm »
Do you ride with your foot covering the rear brake pedal? You could be applying the breaks without meaning too.

How many miles have you done since the garage fixed it?

Steve3351

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Re: Rear brake clunk/hot
« Reply #4 on: 09 July 2019, 09:56:04 pm »
Ho Dude
No i don't ride with my foot on the pedal.....it's about 20K since the brake was done at the shop :faz :smokin

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Re: Rear brake clunk/hot
« Reply #5 on: 09 July 2019, 10:59:24 pm »
Sounds like a sticky caliper. It will need stripping and cleaning.


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Steve3351

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Re: Rear brake clunk/hot
« Reply #6 on: 10 July 2019, 11:15:47 am »
Yes I need to strip and clean...but do i need to order new seals or wot...? :book

bandit

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Re: Rear brake clunk/hot
« Reply #7 on: 10 July 2019, 11:39:43 am »
Yes new seals,brake cleaner possibly new pistons if badly corroded & can't be cleaned some red rubber grease for reassembly,new brake fluid.   


Have you tried just cleaning it, remove pads,pump pistons out a bit on one side by holding the other side in then do the same for the other side, spray pistons with brake cleaner or use meth spirit with a small toothbrush/brush allow to dry, then apply red rubber grease around pistons push them in, pump them out a bit & so on & see if they move easier. Assembly brake pads in caliper remember to apply copper anti seize grease or better still some Ceratec to back of pads.    Smile
« Last Edit: 10 July 2019, 12:06:20 pm by bandit »

Steve3351

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Re: Rear brake clunk/hot
« Reply #8 on: 10 July 2019, 12:32:36 pm »
Thanks Bandit...i will order new seals anyway...and have a look with the caliper in place...
If i do take the caliper off...do i just undo the banjo and let the fluid drain out...?? 8)

darrsi

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Re: Rear brake clunk/hot
« Reply #9 on: 10 July 2019, 01:27:37 pm »
Something else to mention, give the pivot of the rear brake lever a good clean out with either brake cleaner spray or WD40, about once every couple of months.
The crap from roads, and even dirty rain, can clog it up after a while making it feel spongy and not as responsive as it should be.
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bandit

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Re: Rear brake clunk/hot
« Reply #10 on: 10 July 2019, 01:29:07 pm »
Yes you can just undo the banjo but you will need to remove the brake reservoir cap first to relieve the vacuum, don't get any fluid on paintwork if you do wash off with water immediately. While the caliper is off carefully loosen off the two bleed nipples & lightly re-tighten ready for bleeding the caliper later.   
« Last Edit: 10 July 2019, 01:31:24 pm by bandit »

Fazerider

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Re: Rear brake clunk/hot
« Reply #11 on: 10 July 2019, 03:22:32 pm »
Did the mechanic just change the caliper seals or those in the master cylinder as well?
I fear there are a lot of Fazers still being ridden with original rubber in the braking system... Yamaha say the seals should be changed every 4 years.

Steve3351

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Re: Rear brake clunk/hot
« Reply #12 on: 10 July 2019, 06:52:14 pm »
Thanks for advice Foccers... 8)

I don't know of the seals in the rear master cylinder have ever been changed...is it a difficult job....??

Fazerider

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Re: Rear brake clunk/hot
« Reply #13 on: 10 July 2019, 09:29:46 pm »

Thanks for advice Foccers...


I don't know of the seals in the rear master cylinder have ever been changed...is it a difficult job....??
It's not too hard, bleeding all the air out afterwards can be a PITA because of the U-bend path the fluid has to take, but you can loosen the banjo at the top of the master cylinder and let the bubbles out that way.

bandit

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Re: Rear brake clunk/hot
« Reply #14 on: 10 July 2019, 09:58:56 pm »

Thanks for advice Foccers...


I don't know of the seals in the rear master cylinder have ever been changed...is it a difficult job....??
It's not too hard, bleeding all the air out afterwards can be a PITA because of the U-bend path the fluid has to take, but you can loosen the banjo at the top of the master cylinder and let the bubbles out that way.


The air bleeding part might be easier if you leave the reservoir cap on, clamp the brake hose or undo the banjo bolt at the caliper & place end of brake hose into a plastic bag sealed with a elastic band ( don't operate the brake pedal) then when you reconnect the brake hose it will only be the air in the caliper to expel when bleeding.
This is for after changing seals in caliper.   
« Last Edit: 10 July 2019, 10:12:04 pm by bandit »

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Re: Rear brake clunk/hot
« Reply #15 on: 11 July 2019, 12:52:27 am »
Yes you can just undo the banjo but you will need to remove the brake reservoir cap first to relieve the vacuum, don't get any fluid on paintwork if you do wash off with water immediately. While the caliper is off carefully loosen off the two bleed nipples & lightly re-tighten ready for bleeding the caliper later.
There's a vent hole in the reservoir to allow atmospheric pressure in so a vacuum can't form. If the reservoir was fully sealed and there was no vent hole a vacuum would form and it could stop fluid flowing through the system

Steve3351

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Re: Rear brake clunk/hot
« Reply #16 on: 11 July 2019, 12:00:12 pm »
Yes that makes sense...i don't mind loosing all the brake fluid..probably needs to be changed anyway :lol

bandit

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Re: Rear brake clunk/hot
« Reply #17 on: 11 July 2019, 12:32:10 pm »
Yes that makes sense...i don't mind loosing all the brake fluid..probably needs to be changed anyway :lol



But the idea was that clamping/stopping the brake fluid from exiting the brake hose line was to make life easier having only air in the caliper to expel rather than the whole system (which by all accounts is a pig) then you can flush out the old fluid while filling with fresh.  Smile
« Last Edit: 11 July 2019, 12:34:35 pm by bandit »

redmandan

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Re: Rear brake clunk/hot
« Reply #18 on: 11 July 2019, 10:19:03 pm »
Bit of advice regarding seals: only buy genuine OEM, don't bother with knock offs. I got a set for about 3 quid from Wemoto and they didn't fit (they never replied to my complaint either)


The gurus on here pointed me towards Fowlers genuine OEM ones for 35 quid delivered. Expensive? Yes, but if you want your bike back on the road ASAP it's the way to go. Bit of peace of mind as well, these are brakes after all.

Steve3351

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Re: Rear brake clunk/hot
« Reply #19 on: 11 July 2019, 11:42:51 pm »
This is wot i ordered...waiting for delivery...


brumersbikes

[/size]£10.50
Order YAMAHA FZR 400 FZS 600 FAZER FZR REAR BRAKE CALIPER SEAL KIT

[/size][/size]YAMAHA FZR 400 FZS 600 FAZER FZR REAR BRAKE CALIPER SEAL KIT..... :) :rollin :(
« Last Edit: 11 July 2019, 11:45:52 pm by Steve3351 »

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Re: Rear brake clunk/hot
« Reply #20 on: 12 July 2019, 03:04:43 pm »

The OEM caliper is every bit as good as the FZS1000 one which many replace it with (myself included) , but it has a design flaw in that the small drain holes at the bottom get blocked with crud and water/salt will rest within the caliper and corrode it and pads on poorly maintained bikes. The FZS1000 does not have this issue as the bottom of the caliper is completely open like the top.
To sort the OEM  caliper on the FZS600 and 400 properly this kit from Powerhouse is what you need as it includes the inner caliper seals which allows you split the caliper to check out the caliper completely. Yamaha do not supply the small inner seal.
https://i.ebayimg.com/images/g/J9wAAOSwBahU9dJq/s-l1600.jpg