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Bikes, Hints'n'Tips => FZS600 Fazer => Topic started by: helloindustries on 17 November 2014, 02:41:37 pm

Title: [Resolved] [Technical] 'Soft' front brakes
Post by: helloindustries on 17 November 2014, 02:41:37 pm
Recently had a banjo fitting replaced due to a small leak. Brakes were bled, but now feel much less effective than before.
Granted; They were never at 100% as the rotors were bent before i got it. They were straightened out, which sorted as much deformation in the discs as possible, and the brakes were good enough.

All i can think of is that they might need re-bleeding.

Thoughts?


-

Resolved
Leak on right side due to worn washers.
Now replaced, re-bled at all points and back to where they were (which wasn't 100%, and wont be unless i buy new discs).
Title: Re: [Technical] 'Soft' front brakes
Post by: darrsi on 17 November 2014, 05:27:32 pm
Always thought discs were way too thin to be "straightened"?
Any warping of a disc will keep pushing your pads apart so your initial grab at the lever would feel unresponsive.
Other than that it can take a few goes at bleeding before getting them sharp.
Title: Re: [Technical] 'Soft' front brakes
Post by: helloindustries on 17 November 2014, 05:35:42 pm
Always thought discs were way too thin to be "straightened"?
Any warping of a disc will keep pushing your pads apart so your initial grab at the lever would feel unresponsive.
Other than that it can take a few goes at bleeding before getting them sharp.

Initially; I thought the discs were bent when i got the bike, turned out to be bent rotors, which i had straightened.

Likely as you suggest, and i suspect: They probably just need another bleed, though i don't expect to get them up to 100% without spending silly money on rotors, discs, callipers etc... but i'll never do that. Just not worth it considering the initial value and that it's a cat C, and the likely resale value -vs- investment.
Title: Re: [Technical] 'Soft' front brakes
Post by: darrsi on 17 November 2014, 09:15:17 pm
Personally, if i wanted to keep a low budget then i'd consider 2nd hand original discs.
Title: Re: [Technical] 'Soft' front brakes
Post by: Tefer on 17 November 2014, 09:17:15 pm
You can get brand new Ferodo discs for £108 each from M&P.
Title: Re: [Technical] 'Soft' front brakes
Post by: helloindustries on 17 November 2014, 09:18:42 pm
Personally, if i wanted to keep a low budget then i'd consider 2nd hand original discs.

The discs seem pretty straight, well under 1mm of wobble. And then there's no guarantee that 2nd hand discs are any straighter.

You can get brand new Ferodo discs for £108 each from M&P.

And this is why i don't want to spend on new discs.
Title: Re: [Technical] 'Soft' front brakes
Post by: darrsi on 17 November 2014, 10:10:18 pm
Kind of chancy 2nd hand, but if you buy from a breakers they will change them if they're not right.
I've bought them once before and they were fine.
Originals are definitely better to take a chance with though, and it is possible to get ones with lowish mileage on that will last you a good while.
Unfortunately new ones aren't cheap, same as the rear shock too.
Just need to keep an eye out for the bargains, they are out there if you persevere.
Regulars on here will know i had major problems years ago with juddering up front, and i replaced nearly everything, and my last final option was to change my braided brake lines and it turned out that they were the culprit.  :\
Still reckon that if you keep bleeding your brakes then it will improve things though.
Title: Re: [Technical] 'Soft' front brakes
Post by: Tefer on 17 November 2014, 10:13:11 pm
Personally, if i wanted to keep a low budget then i'd consider 2nd hand original discs.

The discs seem pretty straight, well under 1mm of wobble. And then there's no guarantee that 2nd hand discs are any straighter.

You can get brand new Ferodo discs for £108 each from M&P.

And this is why i don't want to spend on new discs.


Brakes are important and that's quite cheap as new OEM ones are about £200 each. Brakes and Tyres i would not scrimp on.


I know what you mean though, not easy.
Title: Re: [Technical] 'Soft' front brakes
Post by: helloindustries on 17 November 2014, 10:14:56 pm
Well, i'll see how i get on with bleeding, and work outwards from there, i guess.
Title: Re: [Technical] 'Soft' front brakes
Post by: helloindustries on 17 November 2014, 10:20:01 pm
Out of interest: What should the thickness of the front brake discs be, anyway?
Title: Re: [Technical] 'Soft' front brakes
Post by: darrsi on 17 November 2014, 11:11:52 pm
Out of interest: What should the thickness of the front brake discs be, anyway?

Don't quote me, but from memory 4.5mm is the limit, but with a 5mm disc.
The pads should do all the work.
I have 6mm discs on mine so "should" be good for a long time.
Saying that, i used HH sintered pads on a new rear EBC Pro-Lite disc and the pads ate it like it was made of cheese. Admittedly i was using the rear more because of my front juddering. Even still i expected better than that.
Title: Re: [Technical] 'Soft' front brakes
Post by: darrsi on 17 November 2014, 11:13:34 pm
Take off your front lever and clean and grease EVERYTHING, it can help too.
Title: Re: [Technical] 'Soft' front brakes
Post by: helloindustries on 17 November 2014, 11:17:47 pm
Take off your front lever and clean and grease EVERYTHING, it can help too.

Good idea.
Title: Re: [Technical] 'Soft' front brakes
Post by: darrsi on 17 November 2014, 11:18:55 pm
Another overlooked simple improvement is clean and oil under the pivot of the rear brake pedal.
Crud builds up due to shite weather, but once cleaned and maintained regularly can make the rear feel very snappy, and it takes seconds to do.  :)
Title: Re: [Technical] 'Soft' front brakes
Post by: helloindustries on 17 November 2014, 11:20:08 pm
Another overlooked simple improvement is clean and oil under the pivot of the rear brake pedal.
Crud builds up due to shite weather, but once cleaned and maintained regularly can make the rear feel very snappy, and it takes seconds to do.  :)

Rear is plenty snappy!
Noticed as much with all the extra rear braking i'm having to do to compensate for the lacking front.
Title: Re: [Technical] 'Soft' front brakes
Post by: darrsi on 18 November 2014, 09:57:58 am
Another overlooked simple improvement is clean and oil under the pivot of the rear brake pedal.
Crud builds up due to shite weather, but once cleaned and maintained regularly can make the rear feel very snappy, and it takes seconds to do.  :)

Rear is plenty snappy!
Noticed as much with all the extra rear braking i'm having to do to compensate for the lacking front.

Clean the pivot anyway on a regular basis, you will notice the difference.
I either use brake cleaner, or WD40, then a bit of 3-in-1 oil, about once a month.
Title: Re: [Technical] 'Soft' front brakes
Post by: darrsi on 18 November 2014, 10:10:49 am
Brake disc wear limit should be stamped on them somewhere by the way.
Title: Re: [Technical] 'Soft' front brakes
Post by: ste131 on 18 November 2014, 03:59:37 pm
Have you tried back bleeding? Sometimes you get a small pocket of air in master cylinder banjo. Take top off and start flicking lever and move steering to full left. Don't forget cloth around reservoir in case it spits back. Sometimes works wonders  :)
Title: Re: [Technical] 'Soft' front brakes
Post by: darrsi on 18 November 2014, 04:28:20 pm
Another trick you can try is loosen the master cylinder cap then tying your brake lever back and leaving it over night with the bike on the centre stand.
You don't wanna spill that shit so put plenty of rags around it just in case.
It forces the bubbles upwards. I've done it many times before to give the brakes that final boost, it normally works very well.
Title: Re: [Technical] 'Soft' front brakes
Post by: helloindustries on 19 November 2014, 01:00:57 am
I had the front brakes bled at both ends today, no air that we could see, but the brakes feel a bit better.
Title: Re: [Technical] 'Soft' front brakes
Post by: His Dudeness on 19 November 2014, 08:37:23 am
Cable tie the lever closed overnight. It can force the air back up to the master cylinder. Do it a few nights in a row
Title: Re: [Technical] 'Soft' front brakes
Post by: unfazed on 20 November 2014, 10:15:25 pm
If the problem was not there before you changed the fitting then it is most likely air.

I presume you are bleeding them correctly.
Pump the lever, hold it, release the nipple, keeping pressure on the lever. do up the nipple, release the lever. Restart pumping the lever again.

If tying up the lever like His Dudeness says does not work try bleed the lines from the master cylinder down by loosening the banjo bolt like the bleed nipples.
If no success, remove the calipers one side at the time and push the pistons back fully, use a clamp or something to hold them in the fully pushed back position. Now bleed them again, you will need a helper to pump the lever, while you open and close the bleed nipple.

Sometime air can get trapped around banjo or in the calipers and this normally resolves it.


Title: Re: [Technical] 'Soft' front brakes
Post by: helloindustries on 20 November 2014, 11:02:44 pm
If the problem was not there before you changed the fitting then it is most likely air.

I presume you are bleeding them correctly.
Pump the lever, hold it, release the nipple, keeping pressure on the lever. do up the nipple, release the lever. Restart pumping the lever again.

If tying up the lever like His Dudeness says does not work try bleed the lines from the master cylinder down by loosening the banjo bolt like the bleed nipples.
If no success, remove the calipers one side at the time and push the pistons back fully, use a clamp or something to hold them in the fully pushed back position. Now bleed them again, you will need a helper to pump the lever, while you open and close the bleed nipple.

Sometime air can get trapped around banjo or in the calipers and this normally resolves it.

They've had a standard bleed at the garage which improved the feel, but i might well whip the callipers off and do as advised.
Title: Re: [Technical] 'Soft' front brakes
Post by: helloindustries on 24 November 2014, 07:57:31 pm
So; I cleaned my callipers/pads/pistons today.

Rear was all good, but the front right had one piston pop out, now my brakes are worse, and there still might be air trapped in the bridging line over the mudguard. Also discovered a leak on the double set of banjos on the right side.

Brakes work, but wouldn't like to have to use them in an emergency.

Back down to the garage in the morning for a proper look, new washers and some investigation.
Title: Re: [Technical] 'Soft' front brakes
Post by: unfazed on 24 November 2014, 11:50:01 pm
So; I cleaned my callipers/pads/pistons today.

Rear was all good, but the front right had one piston pop out, now my brakes are worse, and there still might be air trapped in the bridging line over the mudguard. Also discovered a leak on the double set of banjos on the right side.

Brakes work, but wouldn't like to have to use them in an emergency.

Back down to the garage in the morning for a proper look, new washers and some investigation.

Why are you bridging across the mudguard?  :eek The best method for the fazer is 2 lines from the master cylinder, one to each caliper.
Title: Re: [Technical] 'Soft' front brakes
Post by: helloindustries on 24 November 2014, 11:56:34 pm
Quote
Why are you bridging across the mudguard?  :eek The best method for the fazer is 2 lines from the master cylinder, one to each caliper.

Because that's how it was done. May end up the other way, though. See how it goes tomorrow.

Is there any specific reason that it's the best method?
Title: Re: [Technical] 'Soft' front brakes
Post by: unfazed on 25 November 2014, 01:13:51 am
Equal pressure to both calipers immediately.
Title: Re: [Technical] 'Soft' front brakes
Post by: richfzs on 25 November 2014, 07:51:53 am
Easier to bleed as well. Less joints to make / fail.
Title: Re: [Technical] 'Soft' front brakes
Post by: helloindustries on 25 November 2014, 11:51:19 am
I can see the equal pressure theory working, but there are exactly the same number of joints with either method.

Anyway: Fixed now.
Turns out that the washers on the right side were in need of replacing.