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Discussion Starter · #1 ·
Hi everybody....Today I nearly became the third person I know, to bin an FJR..So advice on rear brakes required.....Please.

It started with the rear brake not releasing fully & becomeing a tw*t to push around....I did the same to the FJR as I did with the GSX....Stripped down brake caliper...removed weather seal O-ring,...Scraped off all the dross from the seal seat...rebuilt.....refitted......worked fine....

Rode 60milesish...all worked fine...

Dabbed the rear for a nice right hander....no release....stained undies....somehow managed to pull up on the side of the road with back wheel locked & smoking (not me.the back wheel) without dropping it, more luck than judgement...

I slackened off the caliper bleed dubury & pumped it 2 or 3 times....this realeased the back wheel enough for me to ride home ( front brake only..

I have had the brake pedel stick before & sorted it with a strip & a regrease....this wasn't that...

I may not be competent with a lot of things...But I tend to get the plot with standard non ABS brake systems....

Any ideas....................??????
 

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The VFR can sometimes suffer from a similar problem and this is down to contamination of the seals causing them to swell.

The only other Yamaha I've owned (a Fazer) was a S*d for this and the calipers needed to be cleaned almost monthly.
 

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Discussion Starter · #3 ·
Thanks for the reply Shakey

That was the problem that I cured..This time the brake locked on hard...& only realeased on slackening the bleed nipple..

Thanks.......Mike
 

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Check the master cylinder could be sticking piston or blocked return port.

If the piston is sticking it will maintain brake pressure to the caliper
 

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Hi Mike,
I had this happen to me once in the 80's and what it was I didnt leave enough slack in the brake pedal and it over heated and locked on couldn't get it off until it cooled down.
 

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sounds as if you've done the job on the actual caliper.
As Belly suggests move onto the master cylinder and the brake pedal.
I've had to strip down the brake pedal a couple times as the shaft gets filled with crud after a while.
 

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Sticking brake

Gotta go with Daftlad, on this one.
Time to strip and clean the rear master, and lube the rear brake pivot .
For the price of the master rebuild kit, you may consider replacing the internals. Make sure the tiny hole in the master is free of anything foreign. Bleed your brakes annually. One other small thing.
While you have the brake pedal off for pivot shaft lube, lift the rubber cap off the rear brake switch and clean the top of the switch out.
Moisture and crud, like to collect in there. I used a spray insterment cleaner/ lube, friendly to plastics. Found it at a electrical supply house.
I had a heck of a time with my brake lite sticking in the ON position.
Because of the above problem.
 

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I had a similar (but not as bad) problem Mike

Ditto what you did and others said above - turned out to be the brake pedal pivot - stripped cleaned, greased and never had a problem since.

Torque settings
Brake caliper bolts 26Nm
Rear master cyclinder bolts 18Nm
Footrest bracket bolts 28Nm
 

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Discussion Starter · #9 ·
Thanks for the advice everybody...I've had the brake pivot problem before, it started playing up at scotfest, & it wasn't that this time.
.I would tend to agree with the master cylinder sudgestions..There was some dros in the resevior bottle which I tipped out instead of flushing through..
.It's possible that some could have made it in to the master cylinder...Even though I flushed it through. I think I'll have to strip it to be sure, as it was what you might call an arse clenching moment :oops:

Thanks again for the advice everybody...........Mike
 

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Definitely check all the return ports in the master cylinder. I had this same problem on an older Yamaha when the dross (we call it splooge) had filled in a tiny return port in the master cylinder bore and would not allow the brake to release. It would, as yours, release when I opened the bleed nipple.
 

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Discussion Starter · #11 ·
Hi madmike2..I've flushed about 1ltr of clean brake fluid through. I'm going to give it a run in the slow lane on Sunday & keep dabbing the brake, that way I can pull on to the hard shoulder if it happens again, failing that it's a strip down :cry: Unfortunatly I'm awaiting a new diaphram for the top up bottle, because it became minced on the re-entry.. For a floppy rubbery thing they are like trying to put a jack in a box back in, anyway the thread of the cap definatly made a big impression on it (about half an inch) :shock: .New one arrives on Saturday, so I'll see what happens.......Thanks again.......Mike
 

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Sorry to breath life into an old thread - but my 2002 is suffering a very similar problem. Rear brake sticks on hard when cold, makes it almost impossible to move around by hand. But after a few hard miles it seems to warm up and free off.

I will try all the steps mentioned before, but going to start with the caliper first. As if the heat is having an effect it's unlikely to be the master cylinder right? Or is my logic way off . . .
 

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Hi Neil, have you stripped & greased the rear brake pivot point ? They are very prone to getting crud in there & then slow to release the rear brake. Not hard to do & might be worth the effort before looking at harder jobs.
 

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Hi Neil, have you stripped & greased the rear brake pivot point ? They are very prone to getting crud in there & then slow to release the rear brake. Not hard to do & might be worth the effort before looking at harder jobs.
Yep done that a few times now - even if i lift the pedal up with my toe the back brake is still on.
 

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Could buy / burrow/ make up a ABS test lead and test out the ABS ECU.

If the calliper is sticking, carefully loosen off the bleed nipple, see if it's under pressure.
It will shoot out, if it is, instead of dribbling out, if so could be some valving within the ABS
If not, most likely a sticking slave cylinder, until you can test out the ABS

The result of a sticking rear brake pivot point

 

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Could buy / burrow/ make up a ABS test lead and test out the ABS ECU.

If the calliper is sticking, carefully loosen off the bleed nipple, see if it's under pressure.
It will shoot out, if it is, instead of dribbling out, if so could be some valving within the ABS
If not, most likely a sticking slave cylinder, until you can test out the ABS
I can 100% rule out the ABS being an issue.

I dont have ABS :)
 

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I dont have ABS
Woops, lol lol lol
Didn't see any bike info in your signature.

That makes it easier.
Still crack off the bleed nipple, if the fluid is under pressure could well be the master cylinder valving.

If that seems ok, it's easy to pop out the caliper piston and see if there is any crud in there.
 

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Woops, lol lol lol
Didn't see any bike info in your signature.

That makes it easier.
Still crack off the bleed nipple, if the fluid is under pressure could well be the master cylinder valving.

If that seems ok, it's easy to pop out the caliper piston and see if there is any crud in there.
I know what i'll be doing tonight then!

Cheers for the info.
 

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I would suspect corrosion on the pad mounting pins or corrosion on the brake pistons, just a matter of pushing them out a little and carefully cleaning around the piston
 

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Just had a looky at the Gen 2 service manual, nothing too hard in it pulling apart the slave / master cylinders, leave the master until last.

Didn't realise that the seals are supposed to be replaced "every 2 years"

As sycophantia mentioned, those pins can get corroded. (antisieze or copper grease)

It should be relatively easy to push the pad & piston back into the calliper.
(like when you have to when reinstalling the rear wheel)
If not, crack open the bleed nipple and try pushing back in again.
Get a rough idea weather it's gunk / corrosion within the slave cylinder or a bigger job with the master.

I'd tend to leave the master cylinder alone, just buy a service kit for it.
It's one of those critical items that you can easy stuff up.
I think it's a Brembo rear master, so kits should easily be available if need be.

 
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