Author Topic: My front brakes are Sh1t (Read 9003 times)

CRH · « **Reply #25 on:** 13 September 2012, 09:50:40 pm »

firstly you ...MUST..be meticulous with the pistons!!...the groove where the seal fits must be spotless!!! before fitting the new seals! try soaking them first in brake fluid b4 fitting!!...after youve done this then smear red rubber grease around them and carefully replace bk into caliper!!...if free enough they will go in easily?..

darrsi · « **Reply #26 on:** 13 September 2012, 10:06:09 pm »

It causes all sorts of problems having sticking pistons, probably even more so if it's just one.

I cleaned my calipers what i thought was reasonably often but had constant trouble.

As my bike is my only transport and i'm on call for work at weekends, i decided i needed a quick fix, and realised that a 2nd hand pair of fully working calipers worked out about the same price as new seals, so i went down that route and it worked a treat.
And i now have a spare set of calipers that i can work on at leisure without having the bike off the road.

The brakes work absolutely fine now, and the slightest grab will stop you in your tracks, and they release properly and the wheel spins very freely.
But i think the issues i had with the other calipers have maybe done something to the discs, possibly hotspots, as i'm still getting a hit/miss when braking, although i'm 99.99% sure they're not warped as such.

I'm putting some new braided Venhill brake lines on at the weekend, just to rule them out, then i s'pose i'll have to get the wallet out again for new discs if that doesn't alter anything? $:\$

So, get them sorted, or changed, and save yourself money in the long run!!!

noggythenog · « **Reply #27 on:** 14 September 2012, 09:15:27 am »

How was your break pad wear jimmy?, my breaks sound very similar to yours, i had a quick glance and it appears that one side is more worn than the other,

If they're seized, does that not always mean rust, if so id rather get new pistons,

Surely the rust will keep coming back otherwise,

I wonder how much a recon caliper costs?

noggythenog · « **Reply #28 on:** 14 September 2012, 09:18:58 am »

Sorry i didnt see darssi's post there, question answered again before i even asked it, now thats service!

Dead Eye · « **Reply #29 on:** 14 September 2012, 09:57:39 am »

I had uneven wear on my front brakes but this turned out to be two different sets of pads (1 from each set in each calliper). Previous owner was being cheap me thinks...

If its uneven and pads went in at the same time (and of the same brand / type) then I'd guess at a sticking piston?

darrsi · « **Reply #30 on:** 14 September 2012, 10:09:32 am »

@noggythenog, i knew you were gonna ask so i thought i'd get in first

Still working on the Euromillions numbers though........

noggythenog · « **Reply #31 on:** 14 September 2012, 11:16:24 am »

Mind made up,gonna buy 2 front calipers plus a piston and seal kit to go on whatever calipers end up not on the bike, hopefuly hav a working bike plus 2 stonking calipers ready to put on next time they act up.

Thats over £200 in parts so far before i even think about braided lines but worth it i reckon.

I suppose even folks with newer bikes have to cough up just as much for bits n bobs.

Cheers for advice, sorry jimmy g for jacking your post, hope you get it sorted out likes.

darrsi · « **Reply #32 on:** 14 September 2012, 11:55:47 am »

Brakes are a very expensive hobby, but they are there to do the ultimate job so it's all worth it in the end!

Dave48 · « **Reply #33 on:** 14 September 2012, 12:20:53 pm »

Dont swap pistons from their original bores unless fitting new ones. Also when cleaning calliper assembly make sure grooves for brake & dust seals are spotless as any dirt/corrosion here will affect fitting of new seals & function of pistons. Use red rubber brake grease sparingly around exposed end of pistons. I use YAMAHA seals because they fit properly first time unlike some pattern seals.Light smear of copper grease on BACK of pads and guide pins that hold pads in position. Dont overtighten calliper bolts to fork leg-use correct torque setting. Stripped calliper threads are an EXPENSIVE mistake!

Jimmygixxer · « **Reply #34 on:** 14 September 2012, 12:24:34 pm »

Quote from: noggythenog on 14 September 2012, 09:15:27 am

How was your break pad wear jimmy?, my breaks sound very similar to yours, i had a quick glance and it appears that one side is more worn than the other,

If they're seized, does that not always mean rust, if so id rather get new pistons,

Surely the rust will keep coming back otherwise,

I wonder how much a recon caliper costs?

I never noticed any difference in pad thickness, i just dumped them without looking much, the old ones did seem very glazed though

Jimmygixxer · « **Reply #35 on:** 14 September 2012, 12:35:29 pm »

I tied back the lever last night and tried it today, a small bit of an improvement, maybe I'm expecting to much.
Hard to explain through words i know, but how much sponginess is normal?

JZS 600 · « **Reply #36 on:** 14 September 2012, 01:06:37 pm »

Just had my brake pads replaced when I had a new front tyre fitted this week. The pads in were EBC and he had Ferodo and SBS in stock.

I said what HH rated pads did he recommend.

He recommended these:

http://www.braketech.com/index.php?option=com_content&view=article&id=64&Itemid=91

Don't ever recall fitting organic pads before but I can say right now after a few miles that they don't have the wooden feel of EBC, which is nice! He said as long as I wasn't doing loads of track days, these will be fine. Cheaper too!

darrsi · « **Reply #37 on:** 14 September 2012, 01:08:14 pm »

There shouldn't really be any sponginess at all if they're working correctly!

noggythenog · « **Reply #38 on:** 14 September 2012, 02:29:18 pm »

Jimmy from what ive heard we should be able to use 1 finger for some serious braking, i use 4,

Hmmmm sounds like some dodgy teenage boast, i best use a better choice of words in future!!!!

Maybe we're both fat foccers!!!!!

darrsi · « **Reply #39 on:** 14 September 2012, 03:42:53 pm »

Ha ha ha, thanks for the Friday compliment, but i've been riding for 25 years and i'm 16 stone

It's only 'cos i recognise your problems because i had them all myself up until recently!!

Jimmygixxer · « **Reply #40 on:** 14 September 2012, 06:24:07 pm »

Quote from: noggythenog on 14 September 2012, 02:29:18 pm

Jimmy from what Ive heard we should be able to use 1 finger for some serious braking, i use 4,

Hmmmm sounds like some dodgy teenage boast, i best use a better choice of words in future!!!!

Maybe we're both fat foccers!!!!!

I could be lighter to be honest, but not that bad

Went and seen the guy who supplied me with the Hel lines, he reckoned my brake wasn't too far off what i should expect.
He recons its unlikely to be the master cylinder seals, if it is it could be a bit of dirt stuck. More likely to be abit of air still trapped.
One other thing, the brake fluid i used was from a sealed bottle which i opened about 4 weeks ago.
Surely it couldn't be buggered with moisture already could it?

noggythenog · « **Reply #41 on:** 14 September 2012, 08:29:16 pm »

Im sure we're all really slim......by american standards!

Ive dieted myself down to a fat b'stard!, only 3 more chins to go!

darrsi · « **Reply #42 on:** 15 September 2012, 01:48:20 am »

I didn't say i was fat, i just said i was 16 stone.

When i get on those speaking scales they say "You are 7ft 4"

Fazerider · « **Reply #43 on:** 15 September 2012, 08:00:58 am »

Brake fluid from a container that was first opened a month ago should be fine unless you've been storing the bottle in the shower.

If it's air in the system that's causing the sponginess it can often be bled out at a banjo rather than a bleed nipple, tiny bubbles tend to stick in corners and are reluctant to find their way to the official exit. Another technique I've used is to take the calipers off and push the pistons in firmly to sweep stuck bubbles in the lines upwards... if you try this do it one caliper at a time, you want to force the bubbles back up to the master cylinder, not pop untended pistons onto the ground.

You mentioned one side has slight pad movement when squeezing the lever, if it's just the pads moving then it points to the seals, but it might be worth taking a closer look. On a couple of occasions I've found the disc to be the cause of the problem, if it's warped (dish-shaped might be a better description) then the pistons use up a lot of lever movement to flatten the disc... that feels the same as air in the system (but is much more expensive to cure).

darrsi · « **Reply #44 on:** 15 September 2012, 08:33:20 am »

Neither of them have mentioned any bad juddering yet, i think the word 'warped' is used a bit too loosely to be honest.
A warped disc is gonna be blatantly felt through the hand when braking at speed. If it is genuinely warped then the disc will spread the pads more when moving so you would have to pump the lever one or two times before getting a horrible juddering response.
Hotspots though, which i believe i have, are very small variations of disc thickness, in my case probably caused by one side of my caliper seizing up and rubbing on the disc by being pushed from one side only and creating too much heat without backing off.
That can be mistaken for a 'warped' disc although technically it's not. I'm getting a hit/miss, grabbing feeling, but only at very low speed braking.
Still bloody costly whichever way i look at it

My bike's getting new Venhill brake lines today/tomorrow, to definitely rule them out, then it's a case of hunting for a sensibly priced pair of discs, which after looking around don't really exist, they're either bloody expensive, or taking the piss expensive!!

The thing about brake issues that i've noticed is that they very slowly get worse over time, so unless you are very meticulous then you tend not to realize anything's wrong for ages.
Once you have them up and running again and functioning correctly you'll be amazed at the difference, and actually be quite shocked at how good these brakes are!

You'll find yourself aiming at jaywalkers just to show off your braking power. Or maybe that's just me?

noggythenog · « **Reply #45 on:** 15 September 2012, 09:20:27 am »

7 foot 4 darssi, i hope youve got an aftermarket screen on yur fazer,

Maybe you could get an old f4 phantom cockpit screen,

Well ive gone for a little stroll down big wimp street and booked my bike into my local bike garage for them to take a look

Shall update when i find out.

Fazerider · « **Reply #46 on:** 15 September 2012, 09:21:05 am »

Agreed, the term "warped" is a bit vague. The only time I've experienced a disc warping (i.e. not flat) it was, as I explained, dish-shaped. There was no run-out and no juddering under braking, it felt exactly like air in the brakes.

darrsi · « **Reply #47 on:** 16 September 2012, 03:53:41 pm »

Read my post " Braided Brake Line failure? ", i've had unexpected results!

noggythenog · « **Reply #48 on:** 16 September 2012, 04:20:29 pm »

Ive been following your other post darsi

I knew all along that it wasnt because your fat

Thats crazy,perhaps youve just been unlucky, you would expect at 100 quid that braided lines would last a very long time, i seem to remember HEL lines having a lifetime warranty according to the world wide interweb,

I kinda thought braided lines were up to industrial standards.

Do you mind shaming the company or brand name involved?

Glad its sorted out though and at least you know everything thats been replaced now,your misfortune is still a help to many others.

Gnasher · « **Reply #49 on:** 16 September 2012, 06:58:50 pm »

After 14yrs you need to fit need to fit new main seals make sure you thoroughly clean the seal rebates out before fitting the new seals and replace the master cylinder seals. Check the discs for thickness and run out, clean the semi floating rivets out as they get clogged up with brake dust and stop floating the disc should move slightly but freely on each rivet if not it will give you spongy brakes!