How to Improve Your Brakes

[Korn]

This guide is for you if your brake calipers look something like this:
https://www.kornel.com/pics/Brakes/P1010002.jpg
Notice the dead brake pads and the somewhat less than clean pistons. No wonder why the brakes are feeling crappy!

Work on one caliper at a time, leaving the other one bolted on. First, find a piece of metal/wood to fit down the central groove of the caliper once the pads (or their remains) are removed. With this in place pump the brake lever until all the pistons come out and press up against your bar like so:
https://www.kornel.com/pics/Brakes/P1010003.jpg

At this point, use your favourite cleaning agent to give the whole lot a good scrubbing - paying particular attention to cleaning the areas of piston that were exposed before. I like to use the "Wizzo Wheels" stuff to clean brakes, not its intended use but it works very well.
Note: Make sure the stuff you use isn't corrosive, or you could damage the pistons.
https://www.kornel.com/pics/Brakes/P1010004.jpg

Now that the caliper is relatively clean you can start on the pistons. Use a small pot of brake fluid to dip cotton wool buds into and then use the buds to clean the pistons and around the seals.
https://www.kornel.com/pics/Brakes/P1010013.jpg

Next take the cap off the master cylinder and very slowly push each piston back into the caliper. If you push too quickly, the fluid won't have time to drain back up into the master cylinder and you'll cause one of the other pistons to push out instead. So remember, do it slowly.
https://www.kornel.com/pics/Brakes/P1010009.jpg

Once the pistons are pushed back into the caliper the level of fluid in the master cylinder will have risen, and depending on when it was last changed it might look rather grotty:
https://www.kornel.com/pics/Brakes/P1010010.jpg

You can take this opportunity to suck some out using a syringe and replace it with fresh fluid.
https://www.kornel.com/pics/Brakes/P10100127.jpg

Once again insert your length of bar into the caliper and pump the lever to bring out the pistons. They should move more easily this time. Depending on how long you have you can repeat the cotton wool bud & brake fluid routine a couple of times, I usually do it twice for each caliper. Once you're happy with the condition of the pistons it's time to move on.
https://www.kornel.com/pics/Brakes/P1010012.jpg

If you're going to replace brake pads give the backs of them a slight smearing with copper grease before inserting them. This stops the pistons sticking to them.
https://www.kornel.com/pics/Brakes/P10100124.jpg

At this point if you want to go the whole hog you can replace your standard rubber hoses with braided steel ones to give the brakes a firmer feel. See Stew's excellent guide for details on how to do this.
https://www.kornel.com/pics/Brakes/P1010018.jpg

Finally try this trick: Leaving the cap off the master cylinder pull the brake lever in and secure it in place.
https://www.kornel.com/pics/Brakes/P1010019.jpg

Leave the bike to stand overnight then in the morning give the calipers and brake lines a good tapping/twising, starting from the bottom and working your way up to the master cylinder. Once you're done release the lever and replace the master cylinder cover.
Note: Cover the top of the master cylinder with a piece of paper or something similar to prevent the brake fluid absorbing moisture from the air.

Voila! Better brakes
I take no responsibility if you muck this up and kill yourself through lack of brakes. Also, don't get brake fluid on your hands - it stings like utter buggery!
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3516 Miles, 11 Countries

[Major_Grooves]

Using this helpful guide, along with Stinkwheel's brake line fitting guide, I tried to strip and clean my brakes, and change to braided brake lines. The reason for doing so: my brakes seized on recently so I haven't been riding the thing for a while.

After buying a nice, but deceiving, tool kit from Argos (160 pieces includes the nails and screws!!) I was ready. Most of it went okay. No seized bolts, brake fluid drained off okay, cleaned the calipers fine. However, I didn't manage to finish the job and I have a couple of questions:

The pistons: First of all, when I pumped the brakes to get the pistons out to clean them only one piston came out. I gave that one a clean with brake fluid but it wasn't too dirty. To get the other piston to come out I had to prevent the first piston from moving further by wedging some wood in there. Then the second piston came out. It was much dirtier and took some cleaning, but looked alot better by the end of it.

My problem is with this bit:

[Major_Grooves]

Should also mention that total time for doing this was about, ahem, 10 hours. It also pissed with some of the heaviest rain ever seen in North London so I had to do it under cover with poor light. I also never realised that maintenance was so bad for your health. After being crouched down at the front caliper for so long (10, bleedin', hours) it's now my legs that have seized up - I can barely walk!
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About me|@Major_Grooves|My company|Digg|Flickr

[feef]

[lap_time]

Love the small print
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One post Gordons - just here to sell.

[stinkwheel]

Shouldn't be leaking from where the fitting joins the brake line

Maybe from round the banjo if the surfaces were mucky/corroded or you tried to reuse a copper washer (see picture). If it is leaking from round the join, sounds like somebody has made a hash of assembling the brake line (which is a worry). It is supposed to be a high pressure hydraulic line, leaks are not part of the equation.

It can take a bit of force to push the pistons back in. If they are being particularly hard, I put the old pads back in and use a bit of flatbar as a lever to force them back. I would reckon a G-clamp would work just as well, remember to use something to stop you marking the alloy of the caliper with the clamp.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[VFR400UK]

To push pads in use 2 large screw drivers facing in opposite directions. pull on them both so that the tips push on one of the pistons and that piston will move in smoothly and effortlessly without the caliper trying to twist round in your hands

[Major_Grooves]

[stinkwheel]

They should've really done that at the suppliers, but if it isn't leaking any more it is probably tight enough. As you say, you would normally require a fair degree of force on the end of a spanner to rotate one of those banjos, tighten accordingly (sorry, I don't have any torque ratings for that)

I had a horrible thought that they had forgotten to crimp the fitting when I read your original description. I think you have been a victim of moderate laziness as opposed to dangerous incompetance from the suppliers on this occasion.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Major_Grooves]

[Major_Grooves]

One more question: any idea what the torque ratings will be for the bolts holding the caliper onto the forks?

I should probably get a Haynes manual.
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About me|@Major_Grooves|My company|Digg|Flickr

[Major_Grooves]

It was all going so well...

I bought a G clamp and managed to get the pistons back in, I got the brake pads and the caliper back onto the disc. Then I went to use the torque wrench to tighten the banjo bolts to 14-24 lb/ft...

Disaster!

The banjo bolt must have already been tight enough or too tight, as I sheared the head of the bolt off. Brake fluid was pissing out of the damn thing!

This was the first time I had ever used a torque wrench, and because the bolt was presumably already tight enough, I never got the "feel" for it tightening.

So, I now need to order more banjo bolts, more brake fluid and start all over again.

I really need this bike to be working my next Thursday so I can ride about Oxford looking at properties.
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About me|@Major_Grooves|My company|Digg|Flickr

[stinkwheel]

Lucky in a way, it could just have easily stripped the thread out of your calliper/master cylinder.

Did you buy new banjo bolts? If so you'll be safe enough re-using the old one, I usually just replace them because they are so cheap to buy with the hose. Either way, they are not bike-specific so shouldn't be hard to get hold of.

You'll need a couple of new copper washers too I'm afraid.

If you are really stuck for them you can re-anneal the ones you have by heating them to cherry red with a blowlamp (or gas cooker ring) and quickly dunking them in cold water. You would then need to gently clean the layer of oxide off the surface using some wire wool, trying to bend the copper as little as possible before fitting.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Major_Grooves]

Yeah I was lucky in a way. I though the bolt might be stuck, but I was able to use a screw driver to unscrew it out.

I thought the banjo bolts might have been specific to the brake line, if not the bike. The old bolts were 10 or 12mm and the new ones were 14mm. Doesn't matter anyway, as I threw the old banjo bolts out when I took them off.

I don't think I could re-anneal the broken bolt. The hole in the banjo bolt actually seems to have become an oval when I fit the pieces back together, suggesting that the bolt has somewhat "twisted" Seeing as that suggests that I had hideously overtightened it before the torque wrench even got to it, I think I will replace the one at the reservoir too.

I think I'll check my local bike shop before I phone Buster's for the bolts as I imagine the carriage for the next day delivery would be much more than the total price of bolts + fluid.
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About me|@Major_Grooves|My company|Digg|Flickr

[Jrod]

I've snapped many an anodised banjo bolt, I just stick with the originals now.

[stinkwheel]

Sorry. I was talking about reannealing the copper washers.

Copper becomes work hardened when subjected to a lot of pressure or bending, once this has happened it won't squidge against the metal surfaces and form a seal. Heating to cherry red then rapidly cooling in water reverses this process and makes it soft again.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Bendy]

[Kickstart]

Hi

Firstly, if it snapped easily were you using alloy fixings with the brake lines? If so take them out and throw them in the bin. Useless for road use, and very dangerous really (they have a habit of corroding from the inside, and then first people often know about it is when they have no brakes).

The pistons should go back into the caliper fairly easily, lubed with a little brake fluid. It sounds like you have a twin piston sliding caliper which should make this easier.

Pump both pistons out, making sure they both come out at the same rate. Eventually one will pop out of the caliper (with fluid peeing all over the place) and the other will be just behind it and hopefully be easy to remove. Then you can clean the pistons up thoroughly off the bike. Now look at the caliper. Inside you will see 2 seals where each piston goes (so 4 seals in total for you I think). Take these out carefully (remember which one goes where) without using anything that will damage them and clean up behind the seals. A common problem is a small amount of corrosion behind the seals pushing them hard onto the pistons. Clean up the inside of the caliper body Then replace the seals (lubed with brake fluid), or better still use new seals. Lube each piston and push them in by hand (make sure you keep them square to the bore).

Then bleed the brakes.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[AcIdBuRnZ]

So how do you go about removing the calipers?

I see on my ZZR there are 2 bolts holding the caliper to the fork leg, and there is a spring clip on the top of the caliper - is this holding the pads in place??? Do I leave this in place, and then remove it once the caliper is off?
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Past: Honda NSR125R >> Kawasaki ER-5a2 >> Kawasaki ZZR-600e1 >> Suzuki GSXR-750Y >> Honda VTR 1000 Firestorm
"Chickity China the Chinese Chicken..."

[Kickstart]

Hi

Just undo the 2 bolts to take the caliper off. The spring clip is mainly there to stop the pads rattling round, and is probably held in place with the same pin/s as the pads.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Major_Grooves]

Bendy - I would take you up on that offer, but I'm actually staying there Thursday and Friday night so that I can look at properties all day Friday and Saturday. Might be beyond the call to lend me a bike for nearly three days.

Keith - Yes they are alloy I think, they were the ones that came with the Goodrich lines, and I was a bit surprised at how easily they snapped. However, I must have hugely over-tightened them. I am going to remove the one at the reservoir as a precaution anyway. I'll nip down to my local bike mechanics tomorrow morning and hopefully they can sell me some decent ones.

The brakes are now drained of brake fluid, so is there anyway I can remove the pistons without having to refill them? I got quite alot of crud off the pistons when I pumped them out to clean them, but I presume there is more crud further down and considering the brakes were seizing on, you could be right about the corrosion being a problem at the seals. Am I going beyond what a mechanical newbie should do by removing the seals?
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About me|@Major_Grooves|My company|Digg|Flickr

[Kickstart]

Hi

You possibly are going too far, depending on how confident you are of the job.

You can get the pistons out with compressed air. But it is probably easiest to refill the system.

If you can get them then replace the seals with new ones (saves worrying about damaging them when taking them out, and any official manual will cover itself by saying not to reuse them).

Those hoses are sometimes sold with the bits still seperate (last set I bought came with a hose and the Banjos in seperate packages). At least it makes it easy to mount the lines without twisting them. They do need to be tight before use.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Kickstart]

Hi

By the way, this is what happens with alloy brake line fittings:-

https://www.alfa-pages.co.uk/TempPicture/mikesBrakes.jpg

This is probably only a short time from failing catastrophically, probably when the brakes are required urgently.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[AcIdBuRnZ]

I've got my brake fluid, copper grease, cotton buds, rubber gloves, just need a syringe, then I'm off to give this a bash.

Calipers look filthy, so I've no idea when this was last done. I couldn't find any caliper cleaner (like the stuff Korn used in the 3rd pic down), so is there anything else I can use instead? Guy at Halfrauds thought a silicone cleaner would be ok, but I didn't want to risk causing any damage
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Past: Honda NSR125R >> Kawasaki ER-5a2 >> Kawasaki ZZR-600e1 >> Suzuki GSXR-750Y >> Honda VTR 1000 Firestorm
"Chickity China the Chinese Chicken..."

[stu_m]